Apply 'go fmt' as suggested in CONTRIBUTING.md.

Add Homebrew install instructions

.github/workflows/release.yml

@@ -7,6 +7,7 @@ on:
 
 permissions:
   contents: write
+  id-token: write
 
 jobs:
   release:
@@ -18,6 +19,8 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
 
+      - uses: sigstore/cosign-installer@cad07c2e89fa2edd6e2d7bab4c1aa38e53f76003 # v4.1.1
+
       - name: Set up Go
         uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6.4.0
         with:

.goreleaser.yaml

@@ -34,6 +34,18 @@ archives:
 checksum:
   name_template: "checksums.txt"
 
+signs:
+  - cmd: cosign
+    certificate: "${artifact}.pem"
+    args:
+      - sign-blob
+      - "--output-certificate=${certificate}"
+      - "--output-signature=${signature}"
+      - "${artifact}"
+      - "--yes"
+    artifacts: checksum
+    output: true
+
 snapshot:
   version_template: "{{ incpatch .Version }}-next"
 

LICENSE

@@ -0,0 +1,232 @@
+GNU GENERAL PUBLIC LICENSE
+Version 3, 29 June 2007
+
+Copyright © 2007 Free Software Foundation, Inc. <https://fsf.org/>
+
+Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
+
+Preamble
+
+The GNU General Public License is a free, copyleft license for software and other kinds of works.
+
+The licenses for most software and other practical works are designed to take away your freedom to share and change the works. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change all versions of a program--to make sure it remains free software for all its users. We, the Free Software Foundation, use the GNU General Public License for most of our software; it applies also to any other work released this way by its authors. You can apply it to your programs, too.
+
+When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for them if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs, and that you know you can do these things.
+
+To protect your rights, we need to prevent others from denying you these rights or asking you to surrender the rights. Therefore, you have certain responsibilities if you distribute copies of the software, or if you modify it: responsibilities to respect the freedom of others.
+
+For example, if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same freedoms that you received. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
+
+Developers that use the GNU GPL protect your rights with two steps: (1) assert copyright on the software, and (2) offer you this License giving you legal permission to copy, distribute and/or modify it.
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+For the developers' and authors' protection, the GPL clearly explains that there is no warranty for this free software. For both users' and authors' sake, the GPL requires that modified versions be marked as changed, so that their problems will not be attributed erroneously to authors of previous versions.
+
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+
+Finally, every program is threatened constantly by software patents. States should not allow patents to restrict development and use of software on general-purpose computers, but in those that do, we wish to avoid the special danger that patents applied to a free program could make it effectively proprietary. To prevent this, the GPL assures that patents cannot be used to render the program non-free.
+
+The precise terms and conditions for copying, distribution and modification follow.
+
+TERMS AND CONDITIONS
+
+0. Definitions.
+
+“This License” refers to version 3 of the GNU General Public License.
+
+“Copyright” also means copyright-like laws that apply to other kinds of works, such as semiconductor masks.
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+“The Program” refers to any copyrightable work licensed under this License. Each licensee is addressed as “you”. “Licensees” and “recipients” may be individuals or organizations.
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+To “propagate” a work means to do anything with it that, without permission, would make you directly or secondarily liable for infringement under applicable copyright law, except executing it on a computer or modifying a private copy. Propagation includes copying, distribution (with or without modification), making available to the public, and in some countries other activities as well.
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+To “convey” a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user through a computer network, with no transfer of a copy, is not conveying.
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+An interactive user interface displays “Appropriate Legal Notices” to the extent that it includes a convenient and prominently visible feature that (1) displays an appropriate copyright notice, and (2) tells the user that there is no warranty for the work (except to the extent that warranties are provided), that licensees may convey the work under this License, and how to view a copy of this License. If the interface presents a list of user commands or options, such as a menu, a prominent item in the list meets this criterion.
+
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+The “source code” for a work means the preferred form of the work for making modifications to it. “Object code” means any non-source form of a work.
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+You may convey verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice; keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty; and give all recipients a copy of this License along with the Program.
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+
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+
+6. Conveying Non-Source Forms.
+You may convey a covered work in object code form under the terms of sections 4 and 5, provided that you also convey the machine-readable Corresponding Source under the terms of this License, in one of these ways:
+
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+
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+
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+
+7. Additional Terms.
+“Additional permissions” are terms that supplement the terms of this License by making exceptions from one or more of its conditions. Additional permissions that are applicable to the entire Program shall be treated as though they were included in this License, to the extent that they are valid under applicable law. If additional permissions apply only to part of the Program, that part may be used separately under those permissions, but the entire Program remains governed by this License without regard to the additional permissions.
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+
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+You may not propagate or modify a covered work except as expressly provided under this License. Any attempt otherwise to propagate or modify it is void, and will automatically terminate your rights under this License (including any patent licenses granted under the third paragraph of section 11).
+
+However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.
+
+Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.
+
+Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, you do not qualify to receive new licenses for the same material under section 10.
+
+9. Acceptance Not Required for Having Copies.
+You are not required to accept this License in order to receive or run a copy of the Program. Ancillary propagation of a covered work occurring solely as a consequence of using peer-to-peer transmission to receive a copy likewise does not require acceptance. However, nothing other than this License grants you permission to propagate or modify any covered work. These actions infringe copyright if you do not accept this License. Therefore, by modifying or propagating a covered work, you indicate your acceptance of this License to do so.
+
+10. Automatic Licensing of Downstream Recipients.
+Each time you convey a covered work, the recipient automatically receives a license from the original licensors, to run, modify and propagate that work, subject to this License. You are not responsible for enforcing compliance by third parties with this License.
+
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+
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+
+11. Patents.
+A “contributor” is a copyright holder who authorizes use under this License of the Program or a work on which the Program is based. The work thus licensed is called the contributor's “contributor version”.
+
+A contributor's “essential patent claims” are all patent claims owned or controlled by the contributor, whether already acquired or hereafter acquired, that would be infringed by some manner, permitted by this License, of making, using, or selling its contributor version, but do not include claims that would be infringed only as a consequence of further modification of the contributor version. For purposes of this definition, “control” includes the right to grant patent sublicenses in a manner consistent with the requirements of this License.
+
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+
+If you convey a covered work, knowingly relying on a patent license, and the Corresponding Source of the work is not available for anyone to copy, free of charge and under the terms of this License, through a publicly available network server or other readily accessible means, then you must either (1) cause the Corresponding Source to be so available, or (2) arrange to deprive yourself of the benefit of the patent license for this particular work, or (3) arrange, in a manner consistent with the requirements of this License, to extend the patent license to downstream recipients. “Knowingly relying” means you have actual knowledge that, but for the patent license, your conveying the covered work in a country, or your recipient's use of the covered work in a country, would infringe one or more identifiable patents in that country that you have reason to believe are valid.
+
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+
+A patent license is “discriminatory” if it does not include within the scope of its coverage, prohibits the exercise of, or is conditioned on the non-exercise of one or more of the rights that are specifically granted under this License. You may not convey a covered work if you are a party to an arrangement with a third party that is in the business of distributing software, under which you make payment to the third party based on the extent of your activity of conveying the work, and under which the third party grants, to any of the parties who would receive the covered work from you, a discriminatory patent license (a) in connection with copies of the covered work conveyed by you (or copies made from those copies), or (b) primarily for and in connection with specific products or compilations that contain the covered work, unless you entered into that arrangement, or that patent license was granted, prior to 28 March 2007.
+
+Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law.
+
+12. No Surrender of Others' Freedom.
+If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.
+
+13. Use with the GNU Affero General Public License.
+Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.
+
+14. Revised Versions of this License.
+The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
+
+Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.
+
+If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.
+
+Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.
+
+15. Disclaimer of Warranty.
+THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+16. Limitation of Liability.
+IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+
+17. Interpretation of Sections 15 and 16.
+If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.
+
+END OF TERMS AND CONDITIONS
+
+How to Apply These Terms to Your New Programs
+
+If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
+
+To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.
+
+     <one line to give the program's name and a brief idea of what it does.>
+     Copyright (C) <year>  <name of author>
+
+     This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+
+     This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+     You should have received a copy of the GNU General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:
+
+     <program>  Copyright (C) <year>  <name of author>
+     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+     This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.
+
+You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see <https://www.gnu.org/licenses/>.
+
+The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read <https://www.gnu.org/philosophy/why-not-lgpl.html>.

README.md

@@ -18,9 +18,7 @@ cooldown:
 
 A 3-day cooldown means that when `lodash` publishes version `4.18.0`, your builds keep using `4.17.21` until 3 days have passed. If the new release turns out to be compromised, you were never exposed.
 
-Resolution order: package override, then ecosystem override, then global default. This lets you set a conservative default and carve out exceptions for packages where you need faster updates.
+Resolution order: package override, then ecosystem override, then global default. This lets you set a conservative default and carve out exceptions for packages where you need faster updates. See [docs/configuration.md](docs/configuration.md) for the full config reference.
-
-Currently works with npm, PyPI, pub.dev, Composer, and Cargo, which all include publish timestamps in their metadata. See [docs/configuration.md](docs/configuration.md) for the full config reference.
 
 ## Supported Registries
 
@@ -28,16 +26,16 @@ Currently works with npm, PyPI, pub.dev, Composer, and Cargo, which all include
 |----------|-------------------|:--------:|:---------:|
 | npm | JavaScript | Yes | ✓ |
 | Cargo | Rust | Yes | ✓ |
-| RubyGems | Ruby | | ✓ |
+| RubyGems | Ruby | Yes | ✓ |
 | Go proxy | Go | | ✓ |
-| Hex | Elixir | | ✓ |
+| Hex | Elixir | Yes* | ✓ |
 | pub.dev | Dart | Yes | ✓ |
 | PyPI | Python | Yes | ✓ |
 | Maven | Java | | ✓ |
-| NuGet | .NET | | ✓ |
+| NuGet | .NET | Yes | ✓ |
 | Composer | PHP | Yes | ✓ |
 | Conan | C/C++ | | ✓ |
-| Conda | Python/R | | ✓ |
+| Conda | Python/R | Yes | ✓ |
 | CRAN | R | | ✓ |
 | Container | Docker/OCI | | ✓ |
 | Debian | Debian/Ubuntu | | ✓ |
@@ -52,6 +50,16 @@ Currently works with npm, PyPI, pub.dev, Composer, and Cargo, which all include
 
 Cooldown requires publish timestamps in metadata. Registries without a "Yes" in the cooldown column either don't expose timestamps or haven't been wired up yet.
 
+\* Hex cooldown requires disabling registry signature verification (`HEX_NO_VERIFY_REPO_ORIGIN=1`) since the proxy re-encodes the protobuf payload.
+
+## Install
+
+```bash
+brew install git-pkgs/git-pkgs/proxy
+```
+
+Or download a binary from the [releases page](https://github.com/git-pkgs/proxy/releases).
+
 ## Quick Start
 
 ```bash
@@ -460,6 +468,44 @@ proxy serve [flags]
 proxy [flags]  # same as 'proxy serve'
 ```
 
+### mirror
+
+Pre-populate the cache from PURLs, SBOM files, or entire registries. Useful for ensuring offline availability or warming the cache before deployments.
+
+```bash
+# Mirror specific package versions
+proxy mirror pkg:npm/lodash@4.17.21 pkg:cargo/serde@1.0.0
+
+# Mirror all versions of a package
+proxy mirror pkg:npm/lodash
+
+# Mirror from a CycloneDX or SPDX SBOM
+proxy mirror --sbom sbom.cdx.json
+
+# Preview what would be mirrored
+proxy mirror --dry-run pkg:npm/lodash
+
+# Control parallelism
+proxy mirror --concurrency 8 pkg:npm/lodash@4.17.21
+```
+
+The mirror command accepts the same storage and database flags as `serve`. Already-cached artifacts are skipped.
+
+A mirror API is also available when the server is running:
+
+```bash
+# Start a mirror job
+curl -X POST http://localhost:8080/api/mirror \
+  -H "Content-Type: application/json" \
+  -d '{"purls": ["pkg:npm/lodash@4.17.21"]}'
+
+# Check job status
+curl http://localhost:8080/api/mirror/mirror-1
+
+# Cancel a running job
+curl -X DELETE http://localhost:8080/api/mirror/mirror-1
+```
+
 ### stats
 
 Show cache statistics without running the server.
@@ -534,6 +580,14 @@ Recently cached:
 | `GET /debian/*` | Debian/APT repository protocol |
 | `GET /rpm/*` | RPM/Yum repository protocol |
 
+### Mirror API
+
+| Endpoint | Description |
+|----------|-------------|
+| `POST /api/mirror` | Start a mirror job (JSON body with `purls`) |
+| `GET /api/mirror/{id}` | Get job status and progress |
+| `DELETE /api/mirror/{id}` | Cancel a running job |
+
 ### Enrichment API
 
 The proxy provides REST endpoints for package metadata enrichment, vulnerability scanning, and outdated detection.

cmd/proxy/main.go

@@ -16,6 +16,7 @@
 //
 //	serve    Start the proxy server (default if no command given)
 //	stats    Show cache statistics
+//	mirror   Pre-populate cache from PURLs, SBOMs, or registries
 //
 // Serve Flags:
 //
@@ -100,7 +101,11 @@ import (
 
 	"github.com/git-pkgs/proxy/internal/config"
 	"github.com/git-pkgs/proxy/internal/database"
+	"github.com/git-pkgs/proxy/internal/handler"
+	"github.com/git-pkgs/proxy/internal/mirror"
 	"github.com/git-pkgs/proxy/internal/server"
+	"github.com/git-pkgs/proxy/internal/storage"
+	"github.com/git-pkgs/registries/fetch"
 )
 
 const defaultTopN = 10
@@ -124,6 +129,10 @@ func main() {
 			os.Args = append(os.Args[:1], os.Args[2:]...)
 			runStats()
 			return
+		case "mirror":
+			os.Args = append(os.Args[:1], os.Args[2:]...)
+			runMirror()
+			return
 		case "-version", "--version":
 			fmt.Printf("proxy %s (%s)\n", Version, Commit)
 			os.Exit(0)
@@ -145,6 +154,7 @@ Usage: proxy [command] [flags]
 Commands:
   serve    Start the proxy server (default)
   stats    Show cache statistics
+  mirror   Pre-populate cache from PURLs, SBOMs, or registries
 
 Run 'proxy <command> -help' for more information on a command.
 
@@ -340,6 +350,151 @@ func runStats() {
 	}
 }
 
+func runMirror() {
+	fs := flag.NewFlagSet("mirror", flag.ExitOnError)
+	configPath := fs.String("config", "", "Path to configuration file")
+	storageURL := fs.String("storage-url", "", "Storage URL (file:// or s3://)")
+	databaseDriver := fs.String("database-driver", "", "Database driver: sqlite or postgres")
+	databasePath := fs.String("database-path", "", "Path to SQLite database file")
+	databaseURL := fs.String("database-url", "", "PostgreSQL connection URL")
+	sbomPath := fs.String("sbom", "", "Path to CycloneDX or SPDX SBOM file")
+	concurrency := fs.Int("concurrency", 4, "Number of parallel downloads") //nolint:mnd // default concurrency
+	dryRun := fs.Bool("dry-run", false, "Show what would be mirrored without downloading")
+
+	fs.Usage = func() {
+		fmt.Fprintf(os.Stderr, "git-pkgs proxy - Pre-populate cache\n\n")
+		fmt.Fprintf(os.Stderr, "Usage: proxy mirror [flags] [purl...]\n\n")
+		fmt.Fprintf(os.Stderr, "Examples:\n")
+		fmt.Fprintf(os.Stderr, "  proxy mirror pkg:npm/lodash@4.17.21\n")
+		fmt.Fprintf(os.Stderr, "  proxy mirror --sbom sbom.cdx.json\n")
+		fmt.Fprintf(os.Stderr, "  proxy mirror pkg:npm/lodash  # all versions\n\n")
+		fmt.Fprintf(os.Stderr, "Flags:\n")
+		fs.PrintDefaults()
+	}
+
+	_ = fs.Parse(os.Args[1:])
+	purls := fs.Args()
+
+	// Determine source
+	var source mirror.Source
+	switch {
+	case *sbomPath != "":
+		source = &mirror.SBOMSource{Path: *sbomPath}
+	case len(purls) > 0:
+		source = &mirror.PURLSource{PURLs: purls}
+	default:
+		fmt.Fprintf(os.Stderr, "error: provide PURLs or --sbom\n")
+		fs.Usage()
+		os.Exit(1)
+	}
+
+	// Load config
+	cfg, err := loadConfig(*configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error loading config: %v\n", err)
+		os.Exit(1)
+	}
+	cfg.LoadFromEnv()
+
+	if *storageURL != "" {
+		cfg.Storage.URL = *storageURL
+	}
+	if *databaseDriver != "" {
+		cfg.Database.Driver = *databaseDriver
+	}
+	if *databasePath != "" {
+		cfg.Database.Path = *databasePath
+	}
+	if *databaseURL != "" {
+		cfg.Database.URL = *databaseURL
+	}
+
+	if err := cfg.Validate(); err != nil {
+		fmt.Fprintf(os.Stderr, "invalid configuration: %v\n", err)
+		os.Exit(1)
+	}
+
+	logger := setupLogger("info", "text")
+
+	// Open database
+	var db *database.DB
+	switch cfg.Database.Driver {
+	case "postgres":
+		db, err = database.OpenPostgresOrCreate(cfg.Database.URL)
+	default:
+		db, err = database.OpenOrCreate(cfg.Database.Path)
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error opening database: %v\n", err)
+		os.Exit(1)
+	}
+	defer func() { _ = db.Close() }()
+
+	if err := db.MigrateSchema(); err != nil {
+		_ = db.Close()
+		fmt.Fprintf(os.Stderr, "error migrating schema: %v\n", err)
+		os.Exit(1) //nolint:gocritic // db closed above
+	}
+
+	// Open storage
+	sURL := cfg.Storage.URL
+	if sURL == "" {
+		sURL = "file://" + cfg.Storage.Path //nolint:staticcheck // backwards compat
+	}
+	store, err := storage.OpenBucket(context.Background(), sURL)
+	if err != nil {
+		_ = db.Close()
+		fmt.Fprintf(os.Stderr, "error opening storage: %v\n", err)
+		os.Exit(1) //nolint:gocritic // db closed above
+	}
+
+	// Build proxy (reuses same pipeline as serve)
+	fetcher := fetch.NewFetcher()
+	resolver := fetch.NewResolver()
+	proxy := handler.NewProxy(db, store, fetcher, resolver, logger)
+	proxy.CacheMetadata = true // mirror always caches metadata
+	proxy.MetadataTTL = cfg.ParseMetadataTTL()
+
+	m := mirror.New(proxy, db, store, logger, *concurrency)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	go func() {
+		sigCh := make(chan os.Signal, 1)
+		signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+		<-sigCh
+		cancel()
+	}()
+
+	if *dryRun {
+		items, err := m.RunDryRun(ctx, source)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %v\n", err)
+			os.Exit(1)
+		}
+		fmt.Printf("Would mirror %d package versions:\n", len(items))
+		for _, item := range items {
+			fmt.Printf("  %s\n", item)
+		}
+		return
+	}
+
+	progress, err := m.Run(ctx, source)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Mirror complete: %d downloaded, %d skipped (cached), %d failed, %s total\n",
+		progress.Completed, progress.Skipped, progress.Failed, formatSize(progress.Bytes))
+
+	if len(progress.Errors) > 0 {
+		fmt.Fprintf(os.Stderr, "\nErrors:\n")
+		for _, e := range progress.Errors {
+			fmt.Fprintf(os.Stderr, "  %s/%s@%s: %s\n", e.Ecosystem, e.Name, e.Version, e.Error)
+		}
+	}
+}
+
 func printStats(db *database.DB, popular, recent int, asJSON bool) error {
 	defer func() { _ = db.Close() }()
 

docs/architecture.md

@@ -161,11 +161,25 @@ vulnerabilities (
     updated_at    DATETIME
 )
 -- indexes: (vuln_id, ecosystem, package_name) unique, (ecosystem, package_name)
+
+metadata_cache (
+    id            INTEGER PRIMARY KEY,
+    ecosystem     TEXT NOT NULL,
+    name          TEXT NOT NULL,
+    storage_path  TEXT NOT NULL,
+    etag          TEXT,
+    content_type  TEXT,
+    size          INTEGER,           -- BIGINT on Postgres
+    fetched_at    DATETIME,
+    created_at    DATETIME,
+    updated_at    DATETIME
+)
+-- indexes: (ecosystem, name) unique
 ```
 
 On PostgreSQL, `INTEGER PRIMARY KEY` becomes `SERIAL`, `DATETIME` becomes `TIMESTAMP`, `INTEGER DEFAULT 0` booleans become `BOOLEAN DEFAULT FALSE`, and size/count columns use `BIGINT`.
 
-The `MigrateSchema()` function handles backward compatibility with older git-pkgs databases by adding missing columns via `ALTER TABLE` as needed.
+The `MigrateSchema()` function handles backward compatibility with older git-pkgs databases by running named migrations that add missing columns and tables. See [migrations.md](migrations.md) for how to add new schema changes.
 
 **Key operations:**
 - `GetPackageByPURL()` - Look up package by PURL
@@ -277,6 +291,12 @@ Version age filtering for supply chain attack mitigation. Configurable at global
 
 Package metadata enrichment. Fetches license, description, homepage, repository URL, and vulnerability data from upstream registries. Powers the `/api/` endpoints and the web UI's package detail pages.
 
+### `internal/mirror`
+
+Selective package mirroring for pre-populating the proxy cache. Supports multiple input sources: individual PURLs (versioned or unversioned), CycloneDX/SPDX SBOM files, and full registry enumeration. Uses a bounded worker pool backed by `errgroup` to download artifacts in parallel, reusing `handler.Proxy.GetOrFetchArtifact()` for the actual fetch-and-cache work.
+
+The package also provides a `MetadataCache` for storing raw upstream metadata blobs so the proxy can serve metadata responses offline. The `JobStore` manages async mirror jobs exposed via the `/api/mirror` endpoints.
+
 ### `internal/config`
 
 Configuration loading.
@@ -326,10 +346,11 @@ Eviction can be implemented as:
 - Ensures clients fetch artifacts through proxy
 - Alternative: Let clients fetch directly, miss cache opportunity
 
-**Why not cache metadata?**
+**Why not cache metadata (by default)?**
 - Simplicity - no invalidation logic needed
 - Fresh data - new versions visible immediately
 - Metadata is small, upstream fetch is fast
+- Set `cache_metadata: true` or use the mirror command to enable metadata caching for offline use via the `metadata_cache` table
 
 **Why stream artifacts?**
 - Memory efficient - don't load large files into RAM

docs/configuration.md

@@ -209,7 +209,68 @@ Durations support days (`7d`), hours (`48h`), and minutes (`30m`). Set to `0` to
 
 Resolution order: package override, then ecosystem override, then global default. This lets you set a conservative default while exempting trusted packages.
 
-Currently supported for npm, PyPI, pub.dev, and Composer. These ecosystems include publish timestamps in their metadata. Other ecosystems (Go, Cargo, RubyGems) would require extra API calls and are not yet supported.
+Currently supported for npm, PyPI, pub.dev, Composer, Cargo, NuGet, Conda, RubyGems, and Hex. These ecosystems include publish timestamps in their metadata.
+
+Note: Hex cooldown requires disabling registry signature verification since the proxy re-encodes the protobuf payload without the original signature. Set `HEX_NO_VERIFY_REPO_ORIGIN=1` or configure your repo with `no_verify: true`.
+
+## Metadata Caching
+
+By default the proxy fetches metadata fresh from upstream on every request. Enable `cache_metadata` to store metadata responses in the database and storage backend for offline fallback. When upstream is unreachable, the proxy serves the last cached copy. ETag-based revalidation avoids re-downloading unchanged metadata.
+
+```yaml
+cache_metadata: true
+```
+
+Or via environment variable: `PROXY_CACHE_METADATA=true`.
+
+The `proxy mirror` command always enables metadata caching regardless of this setting.
+
+### Metadata TTL
+
+When metadata caching is enabled, `metadata_ttl` controls how long a cached response is considered fresh before revalidating with upstream. During the TTL window, cached metadata is served directly without contacting upstream, reducing latency and upstream load.
+
+```yaml
+metadata_ttl: "5m"   # default
+```
+
+Or via environment variable: `PROXY_METADATA_TTL=10m`.
+
+Set to `"0"` to always revalidate with upstream (ETag-based conditional requests still avoid re-downloading unchanged content).
+
+When upstream is unreachable and the cached entry is past its TTL, the proxy serves the stale cached copy with a `Warning: 110 - "Response is Stale"` header so clients can tell the data may be outdated.
+
+## Mirror API
+
+The `/api/mirror` endpoints are disabled by default. Enable them to allow starting mirror jobs via HTTP:
+
+```yaml
+mirror_api: true
+```
+
+Or via environment variable: `PROXY_MIRROR_API=true`.
+
+When disabled, the endpoints are not registered and return 404.
+
+## Mirror Command
+
+The `proxy mirror` command pre-populates the cache from various sources. It accepts the same storage and database flags as `serve`.
+
+| Flag | Default | Description |
+|------|---------|-------------|
+| `--sbom` | | Path to CycloneDX or SPDX SBOM file |
+| `--concurrency` | `4` | Number of parallel downloads |
+| `--dry-run` | `false` | Show what would be mirrored without downloading |
+| `--config` | | Path to configuration file |
+| `--storage-url` | | Storage URL |
+| `--database-driver` | | Database driver |
+| `--database-path` | | SQLite database file |
+| `--database-url` | | PostgreSQL connection URL |
+
+Positional arguments are treated as PURLs:
+
+```bash
+proxy mirror pkg:npm/lodash@4.17.21 pkg:cargo/serde@1.0.0
+```
 
 ## Docker
 

docs/migrations.md

@@ -0,0 +1,51 @@
+# Database Migrations
+
+Schema changes are tracked in a `migrations` table. Each migration has a name and a function. On startup, `MigrateSchema()` loads the set of already-applied names in one query and runs anything new.
+
+Fresh databases created via `Create()` get the full schema and all migrations are recorded as already applied.
+
+## Adding a migration
+
+In `internal/database/schema.go`:
+
+1. Write a migration function:
+
+```go
+func migrateAddWidgetColumn(db *DB) error {
+    hasCol, err := db.HasColumn("packages", "widget")
+    if err != nil {
+        return fmt.Errorf("checking column widget: %w", err)
+    }
+    if !hasCol {
+        colType := "TEXT"
+        if db.dialect == DialectPostgres {
+            colType = "TEXT" // adjust if types differ
+        }
+        if _, err := db.Exec(fmt.Sprintf("ALTER TABLE packages ADD COLUMN widget %s", colType)); err != nil {
+            return fmt.Errorf("adding column widget: %w", err)
+        }
+    }
+    return nil
+}
+```
+
+2. Append it to the `migrations` slice with the next sequential prefix:
+
+```go
+var migrations = []migration{
+    {"001_add_packages_enrichment_columns", migrateAddPackagesEnrichmentColumns},
+    {"002_add_versions_enrichment_columns", migrateAddVersionsEnrichmentColumns},
+    {"003_ensure_artifacts_table", migrateEnsureArtifactsTable},
+    {"004_ensure_vulnerabilities_table", migrateEnsureVulnerabilitiesTable},
+    {"005_add_widget_column", migrateAddWidgetColumn}, // new
+}
+```
+
+3. Add the same column to both `schemaSQLite` and `schemaPostgres` at the top of the file so fresh databases start with the full schema.
+
+## Rules
+
+- Migration functions must be idempotent. Use `HasColumn`/`HasTable` checks or `IF NOT EXISTS` clauses so they're safe to run against a database that already has the change.
+- Handle both SQLite and Postgres dialects. Common differences: `DATETIME` vs `TIMESTAMP`, `INTEGER DEFAULT 0` vs `BOOLEAN DEFAULT FALSE`, `INTEGER PRIMARY KEY` vs `SERIAL PRIMARY KEY`.
+- Never reorder or rename existing entries. The name string is the migration's identity in the database.
+- Never remove old migrations from the list. They won't run on already-migrated databases, but they need to exist for older databases upgrading for the first time.

docs/swagger/docs.go

@@ -297,115 +297,6 @@ const docTemplate = `{
                 }
             }
         },
-        "/api/package/{ecosystem}/{name}": {
-            "get": {
-                "description": "Returns enriched package metadata. URL-encode scoped names (e.g. @scope/name -\u003e %40scope%2Fname).",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get package metadata",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.PackageResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "404": {
-                        "description": "Not Found",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
-        "/api/package/{ecosystem}/{name}/{version}": {
-            "get": {
-                "description": "Returns enriched package+version metadata and vulnerability data.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get version metadata and vulnerabilities",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Version",
-                        "name": "version",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.EnrichmentResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
         "/api/packages": {
             "get": {
                 "produces": [
@@ -505,108 +396,6 @@ const docTemplate = `{
                 }
             }
         },
-        "/api/vulns/{ecosystem}/{name}": {
-            "get": {
-                "description": "Returns vulnerabilities for a package across versions, or for a specific version if provided.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get vulnerabilities for a package or version",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.VulnsResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
-        "/api/vulns/{ecosystem}/{name}/{version}": {
-            "get": {
-                "description": "Returns vulnerabilities for a package across versions, or for a specific version if provided.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get vulnerabilities for a package or version",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Version",
-                        "name": "version",
-                        "in": "path"
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.VulnsResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
         "/health": {
             "get": {
                 "produces": [
@@ -715,29 +504,6 @@ const docTemplate = `{
                 }
             }
         },
-        "server.EnrichmentResponse": {
-            "type": "object",
-            "properties": {
-                "is_outdated": {
-                    "type": "boolean"
-                },
-                "license_category": {
-                    "type": "string"
-                },
-                "package": {
-                    "$ref": "#/definitions/server.PackageResponse"
-                },
-                "version": {
-                    "$ref": "#/definitions/server.VersionResponse"
-                },
-                "vulnerabilities": {
-                    "type": "array",
-                    "items": {
-                        "$ref": "#/definitions/server.VulnResponse"
-                    }
-                }
-            }
-        },
         "server.OutdatedPackage": {
             "type": "object",
             "properties": {
@@ -949,84 +715,6 @@ const docTemplate = `{
                     "type": "integer"
                 }
             }
-        },
-        "server.VersionResponse": {
-            "type": "object",
-            "properties": {
-                "ecosystem": {
-                    "type": "string"
-                },
-                "integrity": {
-                    "type": "string"
-                },
-                "is_outdated": {
-                    "type": "boolean"
-                },
-                "license": {
-                    "type": "string"
-                },
-                "name": {
-                    "type": "string"
-                },
-                "published_at": {
-                    "type": "string"
-                },
-                "version": {
-                    "type": "string"
-                },
-                "yanked": {
-                    "type": "boolean"
-                }
-            }
-        },
-        "server.VulnResponse": {
-            "type": "object",
-            "properties": {
-                "cvss_score": {
-                    "type": "number"
-                },
-                "fixed_version": {
-                    "type": "string"
-                },
-                "id": {
-                    "type": "string"
-                },
-                "references": {
-                    "type": "array",
-                    "items": {
-                        "type": "string"
-                    }
-                },
-                "severity": {
-                    "type": "string"
-                },
-                "summary": {
-                    "type": "string"
-                }
-            }
-        },
-        "server.VulnsResponse": {
-            "type": "object",
-            "properties": {
-                "count": {
-                    "type": "integer"
-                },
-                "ecosystem": {
-                    "type": "string"
-                },
-                "name": {
-                    "type": "string"
-                },
-                "version": {
-                    "type": "string"
-                },
-                "vulnerabilities": {
-                    "type": "array",
-                    "items": {
-                        "$ref": "#/definitions/server.VulnResponse"
-                    }
-                }
-            }
         }
     }
 }`

docs/swagger/swagger.json

@@ -290,115 +290,6 @@
                 }
             }
         },
-        "/api/package/{ecosystem}/{name}": {
-            "get": {
-                "description": "Returns enriched package metadata. URL-encode scoped names (e.g. @scope/name -\u003e %40scope%2Fname).",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get package metadata",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.PackageResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "404": {
-                        "description": "Not Found",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
-        "/api/package/{ecosystem}/{name}/{version}": {
-            "get": {
-                "description": "Returns enriched package+version metadata and vulnerability data.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get version metadata and vulnerabilities",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Version",
-                        "name": "version",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.EnrichmentResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
         "/api/packages": {
             "get": {
                 "produces": [
@@ -498,108 +389,6 @@
                 }
             }
         },
-        "/api/vulns/{ecosystem}/{name}": {
-            "get": {
-                "description": "Returns vulnerabilities for a package across versions, or for a specific version if provided.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get vulnerabilities for a package or version",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.VulnsResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
-        "/api/vulns/{ecosystem}/{name}/{version}": {
-            "get": {
-                "description": "Returns vulnerabilities for a package across versions, or for a specific version if provided.",
-                "produces": [
-                    "application/json"
-                ],
-                "tags": [
-                    "api"
-                ],
-                "summary": "Get vulnerabilities for a package or version",
-                "parameters": [
-                    {
-                        "type": "string",
-                        "description": "Ecosystem",
-                        "name": "ecosystem",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Package name",
-                        "name": "name",
-                        "in": "path",
-                        "required": true
-                    },
-                    {
-                        "type": "string",
-                        "description": "Version",
-                        "name": "version",
-                        "in": "path"
-                    }
-                ],
-                "responses": {
-                    "200": {
-                        "description": "OK",
-                        "schema": {
-                            "$ref": "#/definitions/server.VulnsResponse"
-                        }
-                    },
-                    "400": {
-                        "description": "Bad Request",
-                        "schema": {
-                            "type": "string"
-                        }
-                    },
-                    "500": {
-                        "description": "Internal Server Error",
-                        "schema": {
-                            "type": "string"
-                        }
-                    }
-                }
-            }
-        },
         "/health": {
             "get": {
                 "produces": [
@@ -708,29 +497,6 @@
                 }
             }
         },
-        "server.EnrichmentResponse": {
-            "type": "object",
-            "properties": {
-                "is_outdated": {
-                    "type": "boolean"
-                },
-                "license_category": {
-                    "type": "string"
-                },
-                "package": {
-                    "$ref": "#/definitions/server.PackageResponse"
-                },
-                "version": {
-                    "$ref": "#/definitions/server.VersionResponse"
-                },
-                "vulnerabilities": {
-                    "type": "array",
-                    "items": {
-                        "$ref": "#/definitions/server.VulnResponse"
-                    }
-                }
-            }
-        },
         "server.OutdatedPackage": {
             "type": "object",
             "properties": {
@@ -942,84 +708,6 @@
                     "type": "integer"
                 }
             }
-        },
-        "server.VersionResponse": {
-            "type": "object",
-            "properties": {
-                "ecosystem": {
-                    "type": "string"
-                },
-                "integrity": {
-                    "type": "string"
-                },
-                "is_outdated": {
-                    "type": "boolean"
-                },
-                "license": {
-                    "type": "string"
-                },
-                "name": {
-                    "type": "string"
-                },
-                "published_at": {
-                    "type": "string"
-                },
-                "version": {
-                    "type": "string"
-                },
-                "yanked": {
-                    "type": "boolean"
-                }
-            }
-        },
-        "server.VulnResponse": {
-            "type": "object",
-            "properties": {
-                "cvss_score": {
-                    "type": "number"
-                },
-                "fixed_version": {
-                    "type": "string"
-                },
-                "id": {
-                    "type": "string"
-                },
-                "references": {
-                    "type": "array",
-                    "items": {
-                        "type": "string"
-                    }
-                },
-                "severity": {
-                    "type": "string"
-                },
-                "summary": {
-                    "type": "string"
-                }
-            }
-        },
-        "server.VulnsResponse": {
-            "type": "object",
-            "properties": {
-                "count": {
-                    "type": "integer"
-                },
-                "ecosystem": {
-                    "type": "string"
-                },
-                "name": {
-                    "type": "string"
-                },
-                "version": {
-                    "type": "string"
-                },
-                "vulnerabilities": {
-                    "type": "array",
-                    "items": {
-                        "$ref": "#/definitions/server.VulnResponse"
-                    }
-                }
-            }
         }
     }
 }

go.mod

@@ -3,22 +3,26 @@ module github.com/git-pkgs/proxy
 go 1.25.6
 
 require (
-	github.com/git-pkgs/archives v0.2.0
+	github.com/CycloneDX/cyclonedx-go v0.10.0
-	github.com/git-pkgs/enrichment v0.2.1
+	github.com/git-pkgs/archives v0.2.2
+	github.com/git-pkgs/enrichment v0.2.2
 	github.com/git-pkgs/purl v0.1.10
 	github.com/git-pkgs/registries v0.4.0
 	github.com/git-pkgs/spdx v0.1.2
 	github.com/git-pkgs/vers v0.2.4
-	github.com/git-pkgs/vulns v0.1.3
+	github.com/git-pkgs/vulns v0.1.4
 	github.com/go-chi/chi/v5 v5.2.5
 	github.com/jmoiron/sqlx v1.4.0
-	github.com/lib/pq v1.12.0
+	github.com/lib/pq v1.12.2
 	github.com/prometheus/client_golang v1.23.2
 	github.com/prometheus/client_model v0.6.2
+	github.com/spdx/tools-golang v0.5.7
 	github.com/swaggo/swag v1.16.6
 	gocloud.dev v0.45.0
+	golang.org/x/sync v0.20.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
-	modernc.org/sqlite v1.47.0
+	modernc.org/sqlite v1.48.0
 )
 
 require (
@@ -51,6 +55,7 @@ require (
 	github.com/alfatraining/structtag v1.0.0 // indirect
 	github.com/alingse/asasalint v0.0.11 // indirect
 	github.com/alingse/nilnesserr v0.2.0 // indirect
+	github.com/anchore/go-struct-converter v0.1.0 // indirect
 	github.com/apapsch/go-jsonmerge/v2 v2.0.0 // indirect
 	github.com/ashanbrown/forbidigo/v2 v2.3.0 // indirect
 	github.com/ashanbrown/makezero/v2 v2.1.0 // indirect
@@ -276,7 +281,6 @@ require (
 	golang.org/x/exp/typeparams v0.0.0-20260209203927-2842357ff358 // indirect
 	golang.org/x/mod v0.33.0 // indirect
 	golang.org/x/net v0.51.0 // indirect
-	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.42.0 // indirect
 	golang.org/x/text v0.34.0 // indirect
 	golang.org/x/tools v0.42.0 // indirect
@@ -284,7 +288,6 @@ require (
 	google.golang.org/api v0.269.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260226221140-a57be14db171 // indirect
 	google.golang.org/grpc v1.79.1 // indirect
-	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	honnef.co/go/tools v0.7.0 // indirect
@@ -293,7 +296,7 @@ require (
 	modernc.org/memory v1.11.0 // indirect
 	mvdan.cc/gofumpt v0.9.2 // indirect
 	mvdan.cc/unparam v0.0.0-20251027182757-5beb8c8f8f15 // indirect
-	sigs.k8s.io/yaml v1.3.0 // indirect
+	sigs.k8s.io/yaml v1.6.0 // indirect
 )
 
 tool github.com/golangci/golangci-lint/v2/cmd/golangci-lint

go.sum

@@ -46,6 +46,8 @@ github.com/Antonboom/testifylint v1.6.4/go.mod h1:YO33FROXX2OoUfwjz8g+gUxQXio5i9
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/toml v1.6.0 h1:dRaEfpa2VI55EwlIW72hMRHdWouJeRF7TPYhI+AUQjk=
 github.com/BurntSushi/toml v1.6.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
+github.com/CycloneDX/cyclonedx-go v0.10.0 h1:7xyklU7YD+CUyGzSFIARG18NYLsKVn4QFg04qSsu+7Y=
+github.com/CycloneDX/cyclonedx-go v0.10.0/go.mod h1:vUvbCXQsEm48OI6oOlanxstwNByXjCZ2wuleUlwGEO8=
 github.com/Djarvur/go-err113 v0.1.1 h1:eHfopDqXRwAi+YmCUas75ZE0+hoBHJ2GQNLYRSxao4g=
 github.com/Djarvur/go-err113 v0.1.1/go.mod h1:IaWJdYFLg76t2ihfflPZnM1LIQszWOsFDh2hhhAVF6k=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.30.0 h1:sBEjpZlNHzK1voKq9695PJSX2o5NEXl7/OL3coiIY0c=
@@ -85,6 +87,8 @@ github.com/alingse/asasalint v0.0.11 h1:SFwnQXJ49Kx/1GghOFz1XGqHYKp21Kq1nHad/0WQ
 github.com/alingse/asasalint v0.0.11/go.mod h1:nCaoMhw7a9kSJObvQyVzNTPBDbNpdocqrSP7t/cW5+I=
 github.com/alingse/nilnesserr v0.2.0 h1:raLem5KG7EFVb4UIDAXgrv3N2JIaffeKNtcEXkEWd/w=
 github.com/alingse/nilnesserr v0.2.0/go.mod h1:1xJPrXonEtX7wyTq8Dytns5P2hNzoWymVUIaKm4HNFg=
+github.com/anchore/go-struct-converter v0.1.0 h1:2rDRssAl6mgKBSLNiVCMADgZRhoqtw9dedlWa0OhD30=
+github.com/anchore/go-struct-converter v0.1.0/go.mod h1:rYqSE9HbjzpHTI74vwPvae4ZVYZd1lue2ta6xHPdblA=
 github.com/apapsch/go-jsonmerge/v2 v2.0.0 h1:axGnT1gRIfimI7gJifB699GoE/oq+F2MU7Dml6nw9rQ=
 github.com/apapsch/go-jsonmerge/v2 v2.0.0/go.mod h1:lvDnEdqiQrp0O42VQGgmlKpxL1AP2+08jFMw88y4klk=
 github.com/ashanbrown/forbidigo/v2 v2.3.0 h1:OZZDOchCgsX5gvToVtEBoV2UWbFfI6RKQTir2UZzSxo=
@@ -144,6 +148,8 @@ github.com/bombsimon/wsl/v4 v4.7.0 h1:1Ilm9JBPRczjyUs6hvOPKvd7VL1Q++PL8M0SXBDf+j
 github.com/bombsimon/wsl/v4 v4.7.0/go.mod h1:uV/+6BkffuzSAVYD+yGyld1AChO7/EuLrCF/8xTiapg=
 github.com/bombsimon/wsl/v5 v5.6.0 h1:4z+/sBqC5vUmSp1O0mS+czxwH9+LKXtCWtHH9rZGQL8=
 github.com/bombsimon/wsl/v5 v5.6.0/go.mod h1:Uqt2EfrMj2NV8UGoN1f1Y3m0NpUVCsUdrNCdet+8LvU=
+github.com/bradleyjkemp/cupaloy/v2 v2.8.0 h1:any4BmKE+jGIaMpnU8YgH/I2LPiLBufr6oMMlVBbn9M=
+github.com/bradleyjkemp/cupaloy/v2 v2.8.0/go.mod h1:bm7JXdkRd4BHJk9HpwqAI8BoAY1lps46Enkdqw6aRX0=
 github.com/breml/bidichk v0.3.3 h1:WSM67ztRusf1sMoqH6/c4OBCUlRVTKq+CbSeo0R17sE=
 github.com/breml/bidichk v0.3.3/go.mod h1:ISbsut8OnjB367j5NseXEGGgO/th206dVa427kR8YTE=
 github.com/breml/errchkjson v0.4.1 h1:keFSS8D7A2T0haP9kzZTi7o26r7kE3vymjZNeNDRDwg=
@@ -224,10 +230,10 @@ github.com/fzipp/gocyclo v0.6.0 h1:lsblElZG7d3ALtGMx9fmxeTKZaLLpU8mET09yN4BBLo=
 github.com/fzipp/gocyclo v0.6.0/go.mod h1:rXPyn8fnlpa0R2csP/31uerbiVBugk5whMdlyaLkLoA=
 github.com/ghostiam/protogetter v0.3.20 h1:oW7OPFit2FxZOpmMRPP9FffU4uUpfeE/rEdE1f+MzD0=
 github.com/ghostiam/protogetter v0.3.20/go.mod h1:FjIu5Yfs6FT391m+Fjp3fbAYJ6rkL/J6ySpZBfnODuI=
-github.com/git-pkgs/archives v0.2.0 h1:8OuuGwAB+Eww8/1ayyYpZzP0wVEH0/VWBG3mQrfi9SM=
+github.com/git-pkgs/archives v0.2.2 h1:RxOjrV8RzKicbMVdf2GDKOqIOHZNVjrLY/Pc7KSE/WQ=
-github.com/git-pkgs/archives v0.2.0/go.mod h1:LTJ1iQVFA7otizWMOyiI82NYVmyBWAPRzwu/e30rcXU=
+github.com/git-pkgs/archives v0.2.2/go.mod h1:LTJ1iQVFA7otizWMOyiI82NYVmyBWAPRzwu/e30rcXU=
-github.com/git-pkgs/enrichment v0.2.1 h1:mJJt4YQBzl9aOfu4226ylnC9H6YO9YZDjGpbSPVahKc=
+github.com/git-pkgs/enrichment v0.2.2 h1:vaQu5vs3tjQB5JI0gzBrUCynUc9z3l5byPhgKFaNZrc=
-github.com/git-pkgs/enrichment v0.2.1/go.mod h1:q9eDZpRrUbYwzD4Mtg/T6LRdBMlt2DYRIvVRDULFnKg=
+github.com/git-pkgs/enrichment v0.2.2/go.mod h1:5JWGmlHWcv5HQHUrctcpnRUNpEF5VAixD2z4zvqKejs=
 github.com/git-pkgs/packageurl-go v0.3.1 h1:WM3RBABQZLaRBxgKyYughc3cVBE8KyQxbSC6Jt5ak7M=
 github.com/git-pkgs/packageurl-go v0.3.1/go.mod h1:rcIxiG37BlQLB6FZfgdj9Fm7yjhRQd3l+5o7J0QPAk4=
 github.com/git-pkgs/purl v0.1.10 h1:NMjeF10nzFn3tdQlz6rbmHB+i+YkyrFQxho3e33ePTQ=
@@ -238,8 +244,8 @@ github.com/git-pkgs/spdx v0.1.2 h1:wHSK+CqFsO5N7yDTPvxDmer5LgNEa7vAsiZhi5Aci0A=
 github.com/git-pkgs/spdx v0.1.2/go.mod h1:V98MgZapNgYw54/pdGR82d7RU93qzJoybahbpZqTfw8=
 github.com/git-pkgs/vers v0.2.4 h1:Zr3jR/Xf1i/6cvBaJKPxhCwjzqz7uvYHE0Fhid/GPBk=
 github.com/git-pkgs/vers v0.2.4/go.mod h1:biTbSQK1qdbrsxDEKnqe3Jzclxz8vW6uDcwKjfUGcOo=
-github.com/git-pkgs/vulns v0.1.3 h1:Q9GixxhAYpP5vVDetKNMACHxGnWwB8aE5c9kbE8xxqU=
+github.com/git-pkgs/vulns v0.1.4 h1:SlnGWHNmtdQgABjfrX/I/pVe+DWLbZ5Yi9xg+/De5r8=
-github.com/git-pkgs/vulns v0.1.3/go.mod h1:/PVy7S1oZNVF9X8yVOZ9SX5MFpyVWCtLnIX0kAfPjY0=
+github.com/git-pkgs/vulns v0.1.4/go.mod h1:34xkR7QncIVfxoi78k3YT6Y9DfTEaL7j6PzCqjsRP9U=
 github.com/github/go-spdx/v2 v2.4.0 h1:+4IwVwJJbm3rzvrQ6P1nI9BDMcy3la4RchRy5uehV/M=
 github.com/github/go-spdx/v2 v2.4.0/go.mod h1:/5rwgS0txhGtRdUZwc02bTglzg6HK3FfuEbECKlK2Sg=
 github.com/go-chi/chi/v5 v5.2.5 h1:Eg4myHZBjyvJmAFjFvWgrqDTXFyOzjj7YIm3L3mu6Ug=
@@ -426,8 +432,8 @@ github.com/ldez/usetesting v0.5.0/go.mod h1:Spnb4Qppf8JTuRgblLrEWb7IE6rDmUpGvxY3
 github.com/leonklingele/grouper v1.1.2 h1:o1ARBDLOmmasUaNDesWqWCIFH3u7hoFlM84YrjT3mIY=
 github.com/leonklingele/grouper v1.1.2/go.mod h1:6D0M/HVkhs2yRKRFZUoGjeDy7EZTfFBE9gl4kjmIGkA=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
-github.com/lib/pq v1.12.0 h1:mC1zeiNamwKBecjHarAr26c/+d8V5w/u4J0I/yASbJo=
+github.com/lib/pq v1.12.2 h1:ajJNv84limnK3aPbDIhLtcjrUbqAw/5XNdkuI6KNe/Q=
-github.com/lib/pq v1.12.0/go.mod h1:/p+8NSbOcwzAEI7wiMXFlgydTwcgTr3OSKMsD2BitpA=
+github.com/lib/pq v1.12.2/go.mod h1:/p+8NSbOcwzAEI7wiMXFlgydTwcgTr3OSKMsD2BitpA=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/macabu/inamedparam v0.2.0 h1:VyPYpOc10nkhI2qeNUdh3Zket4fcZjEWe35poddBCpE=
@@ -568,6 +574,8 @@ github.com/sonatard/noctx v0.4.0 h1:7MC/5Gg4SQ4lhLYR6mvOP6mQVSxCrdyiExo7atBs27o=
 github.com/sonatard/noctx v0.4.0/go.mod h1:64XdbzFb18XL4LporKXp8poqZtPKbCrqQ402CV+kJas=
 github.com/sourcegraph/go-diff v0.7.0 h1:9uLlrd5T46OXs5qpp8L/MTltk0zikUGi0sNNyCpA8G0=
 github.com/sourcegraph/go-diff v0.7.0/go.mod h1:iBszgVvyxdc8SFZ7gm69go2KDdt3ag071iBaWPF6cjs=
+github.com/spdx/tools-golang v0.5.7 h1:+sWcKGnhwp3vLdMqPcLdA6QK679vd86cK9hQWH3AwCg=
+github.com/spdx/tools-golang v0.5.7/go.mod h1:jg7w0LOpoNAw6OxKEzCoqPC2GCTj45LyTlVmXubDsYw=
 github.com/spf13/afero v1.15.0 h1:b/YBCLWAJdFWJTN9cLhiXXcD7mzKn9Dm86dNnfyQw1I=
 github.com/spf13/afero v1.15.0/go.mod h1:NC2ByUVxtQs4b3sIUphxK0NioZnmxgyCrfzeuq8lxMg=
 github.com/spf13/cast v1.5.0 h1:rj3WzYc11XZaIZMPKmwP96zkFEnnAmV8s6XbB2aY32w=
@@ -606,6 +614,8 @@ github.com/tenntenn/modver v1.0.1 h1:2klLppGhDgzJrScMpkj9Ujy3rXPUspSjAcev9tSEBgA
 github.com/tenntenn/modver v1.0.1/go.mod h1:bePIyQPb7UeioSRkw3Q0XeMhYZSMx9B8ePqg6SAMGH0=
 github.com/tenntenn/text/transform v0.0.0-20200319021203-7eef512accb3 h1:f+jULpRQGxTSkNYKJ51yaw6ChIqO+Je8UqsTKN/cDag=
 github.com/tenntenn/text/transform v0.0.0-20200319021203-7eef512accb3/go.mod h1:ON8b8w4BN/kE1EOhwT0o+d62W65a6aPw1nouo9LMgyY=
+github.com/terminalstatic/go-xsd-validate v0.1.6 h1:TenYeQ3eY631qNi1/cTmLH/s2slHPRKTTHT+XSHkepo=
+github.com/terminalstatic/go-xsd-validate v0.1.6/go.mod h1:18lsvYFofBflqCrvo1umpABZ99+GneNTw2kEEc8UPJw=
 github.com/tetafro/godot v1.5.4 h1:u1ww+gqpRLiIA16yF2PV1CV1n/X3zhyezbNXC3E14Sg=
 github.com/tetafro/godot v1.5.4/go.mod h1:eOkMrVQurDui411nBY2FA05EYH01r14LuWY/NrVDVcU=
 github.com/timakin/bodyclose v0.0.0-20241222091800-1db5c5ca4d67 h1:9LPGD+jzxMlnk5r6+hJnar67cgpDIz/iyD+rfl5r2Vk=
@@ -628,6 +638,12 @@ github.com/uudashr/gocognit v1.2.0 h1:3BU9aMr1xbhPlvJLSydKwdLN3tEUUrzPSSM8S4hDYR
 github.com/uudashr/gocognit v1.2.0/go.mod h1:k/DdKPI6XBZO1q7HgoV2juESI2/Ofj9AcHPZhBBdrTU=
 github.com/uudashr/iface v1.4.1 h1:J16Xl1wyNX9ofhpHmQ9h9gk5rnv2A6lX/2+APLTo0zU=
 github.com/uudashr/iface v1.4.1/go.mod h1:pbeBPlbuU2qkNDn0mmfrxP2X+wjPMIQAy+r1MBXSXtg=
+github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f h1:J9EGpcZtP0E/raorCMxlFGSTBrsSlaDGf3jU/qvAE2c=
+github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
+github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 h1:EzJWgHovont7NscjpAxXsDA8S8BMYve8Y5+7cuRE7R0=
+github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415/go.mod h1:GwrjFmJcFw6At/Gs6z4yjiIwzuJ1/+UwLxMQDVQXShQ=
+github.com/xeipuuv/gojsonschema v1.2.0 h1:LhYJRs+L4fBtjZUfuSZIKGeVu0QRy8e5Xi7D17UxZ74=
+github.com/xeipuuv/gojsonschema v1.2.0/go.mod h1:anYRn/JVcOK2ZgGU+IjEV4nwlhoK5sQluxsYJ78Id3Y=
 github.com/xen0n/gosmopolitan v1.3.0 h1:zAZI1zefvo7gcpbCOrPSHJZJYA9ZgLfJqtKzZ5pHqQM=
 github.com/xen0n/gosmopolitan v1.3.0/go.mod h1:rckfr5T6o4lBtM1ga7mLGKZmLxswUoH1zxHgNXOsEt4=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
@@ -857,8 +873,8 @@ modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
 modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
 modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
 modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
-modernc.org/sqlite v1.47.0 h1:R1XyaNpoW4Et9yly+I2EeX7pBza/w+pmYee/0HJDyKk=
+modernc.org/sqlite v1.48.0 h1:ElZyLop3Q2mHYk5IFPPXADejZrlHu7APbpB0sF78bq4=
-modernc.org/sqlite v1.47.0/go.mod h1:hWjRO6Tj/5Ik8ieqxQybiEOUXy0NJFNp2tpvVpKlvig=
+modernc.org/sqlite v1.48.0/go.mod h1:hWjRO6Tj/5Ik8ieqxQybiEOUXy0NJFNp2tpvVpKlvig=
 modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
 modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
 modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
@@ -867,5 +883,5 @@ mvdan.cc/gofumpt v0.9.2 h1:zsEMWL8SVKGHNztrx6uZrXdp7AX8r421Vvp23sz7ik4=
 mvdan.cc/gofumpt v0.9.2/go.mod h1:iB7Hn+ai8lPvofHd9ZFGVg2GOr8sBUw1QUWjNbmIL/s=
 mvdan.cc/unparam v0.0.0-20251027182757-5beb8c8f8f15 h1:ssMzja7PDPJV8FStj7hq9IKiuiKhgz9ErWw+m68e7DI=
 mvdan.cc/unparam v0.0.0-20251027182757-5beb8c8f8f15/go.mod h1:4M5MMXl2kW6fivUT6yRGpLLPNfuGtU2Z0cPvFquGDYU=
-sigs.k8s.io/yaml v1.3.0 h1:a2VclLzOGrwOHDiV8EfBGhvjHvP46CtW5j6POvhYGGo=
+sigs.k8s.io/yaml v1.6.0 h1:G8fkbMSAFqgEFgh4b1wmtzDnioxFCUgTZhlbj5P9QYs=
-sigs.k8s.io/yaml v1.3.0/go.mod h1:GeOyir5tyXNByN85N/dRIT9es5UQNerPYEKK56eTBm8=
+sigs.k8s.io/yaml v1.6.0/go.mod h1:796bPqUfzR/0jLAl6XjHl3Ck7MiyVv8dbTdyT3/pMf4=

internal/config/config.go

@@ -55,6 +55,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 
 	"gopkg.in/yaml.v3"
 )
@@ -83,6 +84,20 @@ type Config struct {
 
 	// Cooldown configures version age filtering to mitigate supply chain attacks.
 	Cooldown CooldownConfig `json:"cooldown" yaml:"cooldown"`
+
+	// CacheMetadata enables caching of upstream metadata responses for offline fallback.
+	// When enabled, metadata is stored in the database and storage backend.
+	// The mirror command always enables this regardless of this setting.
+	CacheMetadata bool `json:"cache_metadata" yaml:"cache_metadata"`
+
+	// MetadataTTL is how long cached metadata is considered fresh before
+	// revalidating with upstream. Uses Go duration syntax (e.g. "5m", "1h").
+	// Default: "5m". Set to "0" to always revalidate.
+	MetadataTTL string `json:"metadata_ttl" yaml:"metadata_ttl"`
+
+	// MirrorAPI enables the /api/mirror endpoints for starting mirror jobs via HTTP.
+	// Disabled by default to prevent unauthenticated users from triggering downloads.
+	MirrorAPI bool `json:"mirror_api" yaml:"mirror_api"`
 }
 
 // CooldownConfig configures version cooldown periods.
@@ -306,6 +321,15 @@ func (c *Config) LoadFromEnv() {
 	if v := os.Getenv("PROXY_COOLDOWN_DEFAULT"); v != "" {
 		c.Cooldown.Default = v
 	}
+	if v := os.Getenv("PROXY_CACHE_METADATA"); v != "" {
+		c.CacheMetadata = v == "true" || v == "1"
+	}
+	if v := os.Getenv("PROXY_MIRROR_API"); v != "" {
+		c.MirrorAPI = v == "true" || v == "1"
+	}
+	if v := os.Getenv("PROXY_METADATA_TTL"); v != "" {
+		c.MetadataTTL = v
+	}
 }
 
 // Validate checks the configuration for errors.
@@ -355,9 +379,34 @@ func (c *Config) Validate() error {
 		}
 	}
 
+	// Validate metadata TTL if specified
+	if c.MetadataTTL != "" && c.MetadataTTL != "0" {
+		if _, err := time.ParseDuration(c.MetadataTTL); err != nil {
+			return fmt.Errorf("invalid metadata_ttl %q: %w", c.MetadataTTL, err)
+		}
+	}
+
 	return nil
 }
 
+const defaultMetadataTTL = 5 * time.Minute //nolint:mnd // sensible default
+
+// ParseMetadataTTL returns the metadata TTL duration.
+// Returns 5 minutes if unset, 0 if explicitly disabled.
+func (c *Config) ParseMetadataTTL() time.Duration {
+	if c.MetadataTTL == "" {
+		return defaultMetadataTTL
+	}
+	if c.MetadataTTL == "0" {
+		return 0
+	}
+	d, err := time.ParseDuration(c.MetadataTTL)
+	if err != nil {
+		return defaultMetadataTTL
+	}
+	return d
+}
+
 // ParseSize parses a human-readable size string (e.g., "10GB", "500MB").
 // Returns the size in bytes.
 func ParseSize(s string) (int64, error) {

internal/config/config_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 )
 
 const (
@@ -301,3 +302,56 @@ func TestLoadFileNotFound(t *testing.T) {
 		t.Error("expected error for nonexistent file")
 	}
 }
+
+func TestParseMetadataTTL(t *testing.T) {
+	tests := []struct {
+		name string
+		ttl  string
+		want time.Duration
+	}{
+		{"empty defaults to 5m", "", 5 * time.Minute},
+		{"explicit zero", "0", 0},
+		{"10 minutes", "10m", 10 * time.Minute},
+		{"1 hour", "1h", 1 * time.Hour},
+		{"invalid defaults to 5m", "not-a-duration", 5 * time.Minute},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := Default()
+			cfg.MetadataTTL = tt.ttl
+			got := cfg.ParseMetadataTTL()
+			if got != tt.want {
+				t.Errorf("ParseMetadataTTL() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestValidateMetadataTTL(t *testing.T) {
+	cfg := Default()
+	cfg.MetadataTTL = "invalid"
+	if err := cfg.Validate(); err == nil {
+		t.Error("expected validation error for invalid metadata_ttl")
+	}
+
+	cfg.MetadataTTL = "5m"
+	if err := cfg.Validate(); err != nil {
+		t.Errorf("unexpected error for valid metadata_ttl: %v", err)
+	}
+
+	cfg.MetadataTTL = "0"
+	if err := cfg.Validate(); err != nil {
+		t.Errorf("unexpected error for zero metadata_ttl: %v", err)
+	}
+}
+
+func TestLoadMetadataTTLFromEnv(t *testing.T) {
+	cfg := Default()
+	t.Setenv("PROXY_METADATA_TTL", "10m")
+	cfg.LoadFromEnv()
+
+	if cfg.MetadataTTL != "10m" {
+		t.Errorf("MetadataTTL = %q, want %q", cfg.MetadataTTL, "10m")
+	}
+}

internal/database/database_test.go

@@ -651,58 +651,159 @@ func TestMigrationFromOldSchema(t *testing.T) {
 	}
 	defer func() { _ = db.Close() }()
 
-	// Try to run queries that require new columns - these should fail without migration
+	// Queries that require new columns should fail without migration
-	t.Run("queries should fail without migration", func(t *testing.T) {
+	if _, err := db.GetEnrichmentStats(); err == nil {
-		_, err := db.GetEnrichmentStats()
+		t.Error("GetEnrichmentStats: expected error querying enriched_at column, got nil")
-		if err == nil {
+	}
-			t.Error("GetEnrichmentStats: expected error querying enriched_at column, got nil")
+	if _, err := db.GetPackageByEcosystemName("npm", "test-package"); err == nil {
-		}
+		t.Error("GetPackageByEcosystemName: expected error querying registry_url column, got nil")
-
+	}
-		_, err = db.GetPackageByEcosystemName("npm", "test-package")
+	// SearchPackages should work even with old schema because it uses sql.NullString
-		if err == nil {
+	if _, err := db.SearchPackages("test", "", 10, 0); err != nil {
-			t.Error("GetPackageByEcosystemName: expected error querying registry_url column, got nil")
+		t.Errorf("SearchPackages: unexpected error with old schema: %v", err)
-		}
+	}
-
-		// SearchPackages should work even with old schema because it uses sql.NullString
-		// for nullable columns, which can handle NULL values properly
-		_, err = db.SearchPackages("test", "", 10, 0)
-		if err != nil {
-			t.Errorf("SearchPackages: unexpected error with old schema: %v", err)
-		}
-	})
 
 	// Run migration
-	t.Run("migrate schema", func(t *testing.T) {
+	if err := db.MigrateSchema(); err != nil {
-		if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema failed: %v", err)
-			t.Fatalf("MigrateSchema failed: %v", err)
+	}
-		}
-	})
 
 	// Verify queries work after migration
-	t.Run("queries should work after migration", func(t *testing.T) {
+	stats, err := db.GetEnrichmentStats()
-		stats, err := db.GetEnrichmentStats()
+	if err != nil {
-		if err != nil {
+		t.Errorf("GetEnrichmentStats failed after migration: %v", err)
-			t.Errorf("GetEnrichmentStats failed after migration: %v", err)
+	}
-		}
+	if stats == nil {
-		if stats == nil {
+		t.Error("GetEnrichmentStats returned nil after migration")
-			t.Error("GetEnrichmentStats returned nil after migration")
+	}
-		}
 
-		pkg, err := db.GetPackageByEcosystemName("npm", "test-package")
+	pkg, err := db.GetPackageByEcosystemName("npm", "test-package")
-		if err != nil {
+	if err != nil {
-			t.Errorf("GetPackageByEcosystemName failed after migration: %v", err)
+		t.Errorf("GetPackageByEcosystemName failed after migration: %v", err)
-		}
+	}
-		if pkg == nil {
+	if pkg == nil {
-			t.Fatal("GetPackageByEcosystemName returned nil after migration")
+		t.Fatal("GetPackageByEcosystemName returned nil after migration")
-		}
+	}
-		if pkg.Name != "test-package" {
+	if pkg.Name != "test-package" {
-			t.Errorf("expected package name test-package, got %s", pkg.Name)
+		t.Errorf("expected package name test-package, got %s", pkg.Name)
-		}
+	}
 
-		// Note: SearchPackages not tested here because old timestamp data
+	// Verify migrations were recorded
-		// stored as strings can't be scanned into time.Time. This is a data
+	applied, err := db.appliedMigrations()
-		// migration issue, not a schema migration issue.
+	if err != nil {
-	})
+		t.Fatalf("appliedMigrations failed: %v", err)
+	}
+	for _, m := range migrations {
+		if !applied[m.name] {
+			t.Errorf("migration %s not recorded as applied", m.name)
+		}
+	}
+
+	// Running again should be a no-op
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("second MigrateSchema failed: %v", err)
+	}
+}
+
+func TestFreshDatabaseRecordsMigrations(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "fresh.db")
+
+	db, err := Create(dbPath)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	applied, err := db.appliedMigrations()
+	if err != nil {
+		t.Fatalf("appliedMigrations failed: %v", err)
+	}
+
+	for _, m := range migrations {
+		if !applied[m.name] {
+			t.Errorf("migration %s not recorded in fresh database", m.name)
+		}
+	}
+}
+
+func TestMigrateSchemaSkipsApplied(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "test.db")
+
+	db, err := Create(dbPath)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	// All migrations are already recorded from Create. Running MigrateSchema
+	// should return without running any migration functions.
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema failed: %v", err)
+	}
+
+	// Verify count hasn't changed (no duplicate inserts)
+	var count int
+	if err := db.Get(&count, "SELECT COUNT(*) FROM migrations"); err != nil {
+		t.Fatalf("counting migrations failed: %v", err)
+	}
+	if count != len(migrations) {
+		t.Errorf("expected %d migrations, got %d", len(migrations), count)
+	}
+}
+
+func TestMigrateSchemaUpgradeFromFullyMigrated(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "existing.db")
+
+	// Simulate an existing proxy database that has the full current schema
+	// but no migrations table (i.e. it was running the previous version).
+	sqlDB, err := sql.Open("sqlite", dbPath)
+	if err != nil {
+		t.Fatalf("failed to open database: %v", err)
+	}
+
+	if _, err := sqlDB.Exec(schemaSQLite); err != nil {
+		t.Fatalf("failed to create schema: %v", err)
+	}
+	// Drop the migrations table that schemaSQLite now includes
+	if _, err := sqlDB.Exec("DROP TABLE migrations"); err != nil {
+		t.Fatalf("failed to drop migrations table: %v", err)
+	}
+	if _, err := sqlDB.Exec("INSERT INTO schema_info (version) VALUES (1)"); err != nil {
+		t.Fatalf("failed to set schema version: %v", err)
+	}
+	if err := sqlDB.Close(); err != nil {
+		t.Fatalf("failed to close database: %v", err)
+	}
+
+	db, err := Open(dbPath)
+	if err != nil {
+		t.Fatalf("Open failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	// This should create the migrations table and record all migrations
+	// without altering any tables (everything already exists).
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema failed: %v", err)
+	}
+
+	applied, err := db.appliedMigrations()
+	if err != nil {
+		t.Fatalf("appliedMigrations failed: %v", err)
+	}
+	for _, m := range migrations {
+		if !applied[m.name] {
+			t.Errorf("migration %s not recorded after upgrade", m.name)
+		}
+	}
+
+	// Second run should be the fast path (single SELECT)
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("second MigrateSchema failed: %v", err)
+	}
 }
 
 func TestConcurrentWrites(t *testing.T) {
@@ -890,3 +991,26 @@ func TestSearchPackagesWithValues(t *testing.T) {
 		t.Errorf("expected 10 hits, got %d", result.Hits)
 	}
 }
+
+func BenchmarkMigrateSchemaFullyMigrated(b *testing.B) {
+	dir := b.TempDir()
+	dbPath := filepath.Join(dir, "bench.db")
+
+	db, err := Create(dbPath)
+	if err != nil {
+		b.Fatalf("Create failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	// First call to ensure everything is migrated
+	if err := db.MigrateSchema(); err != nil {
+		b.Fatalf("initial MigrateSchema failed: %v", err)
+	}
+
+	b.ResetTimer()
+	for b.Loop() {
+		if err := db.MigrateSchema(); err != nil {
+			b.Fatalf("MigrateSchema failed: %v", err)
+		}
+	}
+}

internal/database/metadata_cache_test.go

@@ -0,0 +1,180 @@
+package database
+
+import (
+	"database/sql"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func setupMetadataCacheDB(t *testing.T) *DB {
+	t.Helper()
+	dbPath := filepath.Join(t.TempDir(), "test.db")
+	db, err := Create(dbPath)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema failed: %v", err)
+	}
+	t.Cleanup(func() { _ = db.Close() })
+	return db
+}
+
+func TestUpsertAndGetMetadataCache(t *testing.T) {
+	db := setupMetadataCacheDB(t)
+
+	entry := &MetadataCacheEntry{
+		Ecosystem:   testEcosystemNPM,
+		Name:        "lodash",
+		StoragePath: "_metadata/npm/lodash/metadata",
+		ETag:        sql.NullString{String: `"abc123"`, Valid: true},
+		ContentType: sql.NullString{String: "application/json", Valid: true},
+		Size:        sql.NullInt64{Int64: 1024, Valid: true},
+		FetchedAt:   sql.NullTime{Time: time.Now(), Valid: true},
+	}
+
+	err := db.UpsertMetadataCache(entry)
+	if err != nil {
+		t.Fatalf("UpsertMetadataCache() error = %v", err)
+	}
+
+	got, err := db.GetMetadataCache(testEcosystemNPM, "lodash")
+	if err != nil {
+		t.Fatalf("GetMetadataCache() error = %v", err)
+	}
+	if got == nil {
+		t.Fatal("GetMetadataCache() returned nil")
+	}
+
+	if got.Ecosystem != testEcosystemNPM {
+		t.Errorf("ecosystem = %q, want %q", got.Ecosystem, testEcosystemNPM)
+	}
+	if got.Name != "lodash" {
+		t.Errorf("name = %q, want %q", got.Name, "lodash")
+	}
+	if got.StoragePath != "_metadata/npm/lodash/metadata" {
+		t.Errorf("storage_path = %q, want %q", got.StoragePath, "_metadata/npm/lodash/metadata")
+	}
+	if !got.ETag.Valid || got.ETag.String != `"abc123"` {
+		t.Errorf("etag = %v, want %q", got.ETag, `"abc123"`)
+	}
+	if !got.ContentType.Valid || got.ContentType.String != "application/json" {
+		t.Errorf("content_type = %v, want %q", got.ContentType, "application/json")
+	}
+	if !got.Size.Valid || got.Size.Int64 != 1024 {
+		t.Errorf("size = %v, want 1024", got.Size)
+	}
+}
+
+func TestGetMetadataCacheMiss(t *testing.T) {
+	db := setupMetadataCacheDB(t)
+
+	got, err := db.GetMetadataCache(testEcosystemNPM, "nonexistent")
+	if err != nil {
+		t.Fatalf("GetMetadataCache() error = %v", err)
+	}
+	if got != nil {
+		t.Errorf("expected nil for cache miss, got %v", got)
+	}
+}
+
+func TestUpsertMetadataCacheOverwrite(t *testing.T) {
+	db := setupMetadataCacheDB(t)
+
+	// First insert
+	entry1 := &MetadataCacheEntry{
+		Ecosystem:   testEcosystemNPM,
+		Name:        "lodash",
+		StoragePath: "_metadata/npm/lodash/metadata",
+		ETag:        sql.NullString{String: `"v1"`, Valid: true},
+		ContentType: sql.NullString{String: "application/json", Valid: true},
+		Size:        sql.NullInt64{Int64: 100, Valid: true},
+		FetchedAt:   sql.NullTime{Time: time.Now(), Valid: true},
+	}
+	if err := db.UpsertMetadataCache(entry1); err != nil {
+		t.Fatalf("first UpsertMetadataCache() error = %v", err)
+	}
+
+	// Second insert (same ecosystem+name, different etag and size)
+	entry2 := &MetadataCacheEntry{
+		Ecosystem:   testEcosystemNPM,
+		Name:        "lodash",
+		StoragePath: "_metadata/npm/lodash/metadata",
+		ETag:        sql.NullString{String: `"v2"`, Valid: true},
+		ContentType: sql.NullString{String: "application/json", Valid: true},
+		Size:        sql.NullInt64{Int64: 200, Valid: true},
+		FetchedAt:   sql.NullTime{Time: time.Now(), Valid: true},
+	}
+	if err := db.UpsertMetadataCache(entry2); err != nil {
+		t.Fatalf("second UpsertMetadataCache() error = %v", err)
+	}
+
+	got, err := db.GetMetadataCache(testEcosystemNPM, "lodash")
+	if err != nil {
+		t.Fatalf("GetMetadataCache() error = %v", err)
+	}
+	if got == nil {
+		t.Fatal("expected entry after overwrite")
+	}
+	if got.ETag.String != `"v2"` {
+		t.Errorf("etag = %q, want %q", got.ETag.String, `"v2"`)
+	}
+	if got.Size.Int64 != 200 {
+		t.Errorf("size = %d, want 200", got.Size.Int64)
+	}
+}
+
+func TestUpsertMetadataCacheNullableFields(t *testing.T) {
+	db := setupMetadataCacheDB(t)
+
+	entry := &MetadataCacheEntry{
+		Ecosystem:   "pypi",
+		Name:        "requests",
+		StoragePath: "_metadata/pypi/requests/metadata",
+	}
+
+	if err := db.UpsertMetadataCache(entry); err != nil {
+		t.Fatalf("UpsertMetadataCache() error = %v", err)
+	}
+
+	got, err := db.GetMetadataCache("pypi", "requests")
+	if err != nil {
+		t.Fatalf("GetMetadataCache() error = %v", err)
+	}
+	if got == nil {
+		t.Fatal("expected entry")
+	}
+	if got.ETag.Valid {
+		t.Error("expected null etag")
+	}
+	if got.ContentType.Valid {
+		t.Error("expected null content_type")
+	}
+	if got.Size.Valid {
+		t.Error("expected null size")
+	}
+}
+
+func TestMetadataCacheTableCreatedByMigration(t *testing.T) {
+	// Create a DB without the metadata_cache table, then migrate
+	dbPath := filepath.Join(t.TempDir(), "test.db")
+	db, err := Create(dbPath)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	// MigrateSchema should create the metadata_cache table
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema() error = %v", err)
+	}
+
+	has, err := db.HasTable("metadata_cache")
+	if err != nil {
+		t.Fatalf("HasTable() error = %v", err)
+	}
+	if !has {
+		t.Error("metadata_cache table should exist after migration")
+	}
+}

internal/database/queries.go

@@ -887,3 +887,66 @@ func (db *DB) CountCachedPackages(ecosystem string) (int64, error) {
 	err = db.Get(&count, query, args...)
 	return count, err
 }
+
+// Metadata cache queries
+
+func (db *DB) GetMetadataCache(ecosystem, name string) (*MetadataCacheEntry, error) {
+	var entry MetadataCacheEntry
+	query := db.Rebind(`
+		SELECT id, ecosystem, name, storage_path, etag, content_type,
+		       size, last_modified, fetched_at, created_at, updated_at
+		FROM metadata_cache WHERE ecosystem = ? AND name = ?
+	`)
+	err := db.Get(&entry, query, ecosystem, name)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &entry, nil
+}
+
+func (db *DB) UpsertMetadataCache(entry *MetadataCacheEntry) error {
+	now := time.Now()
+	var query string
+
+	if db.dialect == DialectPostgres {
+		query = `
+			INSERT INTO metadata_cache (ecosystem, name, storage_path, etag, content_type,
+			                            size, last_modified, fetched_at, created_at, updated_at)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
+			ON CONFLICT(ecosystem, name) DO UPDATE SET
+				storage_path = EXCLUDED.storage_path,
+				etag = EXCLUDED.etag,
+				content_type = EXCLUDED.content_type,
+				size = EXCLUDED.size,
+				last_modified = EXCLUDED.last_modified,
+				fetched_at = EXCLUDED.fetched_at,
+				updated_at = EXCLUDED.updated_at
+		`
+	} else {
+		query = `
+			INSERT INTO metadata_cache (ecosystem, name, storage_path, etag, content_type,
+			                            size, last_modified, fetched_at, created_at, updated_at)
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+			ON CONFLICT(ecosystem, name) DO UPDATE SET
+				storage_path = excluded.storage_path,
+				etag = excluded.etag,
+				content_type = excluded.content_type,
+				size = excluded.size,
+				last_modified = excluded.last_modified,
+				fetched_at = excluded.fetched_at,
+				updated_at = excluded.updated_at
+		`
+	}
+
+	_, err := db.Exec(query,
+		entry.Ecosystem, entry.Name, entry.StoragePath, entry.ETag,
+		entry.ContentType, entry.Size, entry.LastModified, entry.FetchedAt, now, now,
+	)
+	if err != nil {
+		return fmt.Errorf("upserting metadata cache: %w", err)
+	}
+	return nil
+}

internal/database/schema.go

@@ -1,6 +1,10 @@
 package database
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+	"time"
+)
 
 const postgresTimestamp = "TIMESTAMP"
 
@@ -86,6 +90,26 @@ CREATE TABLE IF NOT EXISTS vulnerabilities (
 );
 CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
 CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
+
+CREATE TABLE IF NOT EXISTS metadata_cache (
+	id INTEGER PRIMARY KEY,
+	ecosystem TEXT NOT NULL,
+	name TEXT NOT NULL,
+	storage_path TEXT NOT NULL,
+	etag TEXT,
+	content_type TEXT,
+	size INTEGER,
+	last_modified DATETIME,
+	fetched_at DATETIME,
+	created_at DATETIME,
+	updated_at DATETIME
+);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_metadata_eco_name ON metadata_cache(ecosystem, name);
+
+CREATE TABLE IF NOT EXISTS migrations (
+	name TEXT NOT NULL PRIMARY KEY,
+	applied_at DATETIME NOT NULL
+);
 `
 
 var schemaPostgres = `
@@ -166,6 +190,26 @@ CREATE TABLE IF NOT EXISTS vulnerabilities (
 );
 CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
 CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
+
+CREATE TABLE IF NOT EXISTS metadata_cache (
+	id SERIAL PRIMARY KEY,
+	ecosystem TEXT NOT NULL,
+	name TEXT NOT NULL,
+	storage_path TEXT NOT NULL,
+	etag TEXT,
+	content_type TEXT,
+	size BIGINT,
+	last_modified TIMESTAMP,
+	fetched_at TIMESTAMP,
+	created_at TIMESTAMP,
+	updated_at TIMESTAMP
+);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_metadata_eco_name ON metadata_cache(ecosystem, name);
+
+CREATE TABLE IF NOT EXISTS migrations (
+	name TEXT NOT NULL PRIMARY KEY,
+	applied_at TIMESTAMP NOT NULL
+);
 `
 
 // schemaArtifactsOnly contains just the artifacts table for adding to existing git-pkgs databases.
@@ -232,6 +276,11 @@ func (db *DB) CreateSchema() error {
 		return fmt.Errorf("setting schema version: %w", err)
 	}
 
+	// Record all migrations as applied since the full schema is already current.
+	if err := db.recordAllMigrations(); err != nil {
+		return fmt.Errorf("recording migrations: %w", err)
+	}
+
 	return db.OptimizeForReads()
 }
 
@@ -292,24 +341,136 @@ func (db *DB) HasColumn(table, column string) (bool, error) {
 	return exists, err
 }
 
-// MigrateSchema adds missing columns to existing tables for backward compatibility.
+// migration represents a named schema migration.
+type migration struct {
+	name string
+	fn   func(db *DB) error
+}
+
+// migrations is the ordered list of all schema migrations. See
+// docs/migrations.md for how to add new ones.
+var migrations = []migration{
+	{"001_add_packages_enrichment_columns", migrateAddPackagesEnrichmentColumns},
+	{"002_add_versions_enrichment_columns", migrateAddVersionsEnrichmentColumns},
+	{"003_ensure_artifacts_table", migrateEnsureArtifactsTable},
+	{"004_ensure_vulnerabilities_table", migrateEnsureVulnerabilitiesTable},
+	{"005_ensure_metadata_cache_table", migrateEnsureMetadataCacheTable},
+}
+
+// isTableNotFound returns true if the error indicates a missing table.
+// SQLite returns "no such table: X", Postgres returns "relation \"X\" does not exist".
+func isTableNotFound(err error) bool {
+	msg := err.Error()
+	return strings.Contains(msg, "no such table") ||
+		strings.Contains(msg, "does not exist")
+}
+
+// createMigrationsTable creates the migrations table.
+func (db *DB) createMigrationsTable() error {
+	var ts string
+	if db.dialect == DialectPostgres {
+		ts = "TIMESTAMP"
+	} else {
+		ts = "DATETIME"
+	}
+
+	query := fmt.Sprintf(`CREATE TABLE IF NOT EXISTS migrations (
+		name TEXT NOT NULL PRIMARY KEY,
+		applied_at %s NOT NULL
+	)`, ts)
+
+	if _, err := db.Exec(query); err != nil {
+		return fmt.Errorf("creating migrations table: %w", err)
+	}
+	return nil
+}
+
+// appliedMigrations returns the set of migration names that have been recorded.
+// Returns nil if the migrations table does not exist yet.
+func (db *DB) appliedMigrations() (map[string]bool, error) {
+	var names []string
+	err := db.Select(&names, "SELECT name FROM migrations")
+	if err != nil {
+		// Table doesn't exist yet — this is a pre-migration database.
+		if isTableNotFound(err) {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("loading applied migrations: %w", err)
+	}
+
+	applied := make(map[string]bool, len(names))
+	for _, name := range names {
+		applied[name] = true
+	}
+	return applied, nil
+}
+
+// recordMigration inserts a migration name into the migrations table.
+func (db *DB) recordMigration(name string) error {
+	query := db.Rebind("INSERT INTO migrations (name, applied_at) VALUES (?, ?)")
+	if _, err := db.Exec(query, name, time.Now().UTC()); err != nil {
+		return fmt.Errorf("recording migration %s: %w", name, err)
+	}
+	return nil
+}
+
+// recordAllMigrations marks every known migration as applied.
+func (db *DB) recordAllMigrations() error {
+	for _, m := range migrations {
+		if err := db.recordMigration(m.name); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// MigrateSchema applies any unapplied migrations in order.
+// For a fully migrated database this executes a single SELECT query.
 func (db *DB) MigrateSchema() error {
-	// Check and add missing columns to packages table
+	applied, err := db.appliedMigrations()
-	packagesColumns := map[string]string{
+	if err != nil {
-		"registry_url":     "TEXT",
+		return err
-		"supplier_name":    "TEXT",
+	}
-		"supplier_type":    "TEXT",
+
-		"source":           "TEXT",
+	// If the migrations table didn't exist, create it now.
-		"enriched_at":      "DATETIME",
+	if applied == nil {
-		"vulns_synced_at":  "DATETIME",
+		if err := db.createMigrationsTable(); err != nil {
+			return err
+		}
+		applied = make(map[string]bool)
+	}
+
+	for _, m := range migrations {
+		if applied[m.name] {
+			continue
+		}
+		if err := m.fn(db); err != nil {
+			return fmt.Errorf("migration %s: %w", m.name, err)
+		}
+		if err := db.recordMigration(m.name); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func migrateAddPackagesEnrichmentColumns(db *DB) error {
+	columns := map[string]string{
+		"registry_url":    "TEXT",
+		"supplier_name":   "TEXT",
+		"supplier_type":   "TEXT",
+		"source":          "TEXT",
+		"enriched_at":     "DATETIME",
+		"vulns_synced_at": "DATETIME",
 	}
 
 	if db.dialect == DialectPostgres {
-		packagesColumns["enriched_at"] = postgresTimestamp
+		columns["enriched_at"] = postgresTimestamp
-		packagesColumns["vulns_synced_at"] = postgresTimestamp
+		columns["vulns_synced_at"] = postgresTimestamp
 	}
 
-	for column, colType := range packagesColumns {
+	for column, colType := range columns {
 		hasCol, err := db.HasColumn("packages", column)
 		if err != nil {
 			return fmt.Errorf("checking column %s: %w", column, err)
@@ -321,9 +482,11 @@ func (db *DB) MigrateSchema() error {
 			}
 		}
 	}
+	return nil
+}
 
-	// Check and add missing columns to versions table
+func migrateAddVersionsEnrichmentColumns(db *DB) error {
-	versionsColumns := map[string]string{
+	columns := map[string]string{
 		"integrity":   "TEXT",
 		"yanked":      "INTEGER DEFAULT 0",
 		"source":      "TEXT",
@@ -331,11 +494,11 @@ func (db *DB) MigrateSchema() error {
 	}
 
 	if db.dialect == DialectPostgres {
-		versionsColumns["yanked"] = "BOOLEAN DEFAULT FALSE"
+		columns["yanked"] = "BOOLEAN DEFAULT FALSE"
-		versionsColumns["enriched_at"] = postgresTimestamp
+		columns["enriched_at"] = postgresTimestamp
 	}
 
-	for column, colType := range versionsColumns {
+	for column, colType := range columns {
 		hasCol, err := db.HasColumn("versions", column)
 		if err != nil {
 			return fmt.Errorf("checking column %s: %w", column, err)
@@ -347,62 +510,121 @@ func (db *DB) MigrateSchema() error {
 			}
 		}
 	}
+	return nil
+}
 
-	// Ensure artifacts table exists
+func migrateEnsureArtifactsTable(db *DB) error {
-	if err := db.EnsureArtifactsTable(); err != nil {
+	return db.EnsureArtifactsTable()
-		return fmt.Errorf("ensuring artifacts table: %w", err)
+}
-	}
 
-	// Ensure vulnerabilities table exists
+func migrateEnsureVulnerabilitiesTable(db *DB) error {
 	hasVulns, err := db.HasTable("vulnerabilities")
 	if err != nil {
 		return fmt.Errorf("checking vulnerabilities table: %w", err)
 	}
-	if !hasVulns {
+	if hasVulns {
-		var vulnSchema string
+		return nil
-		if db.dialect == DialectPostgres {
+	}
-			vulnSchema = `
+
-				CREATE TABLE vulnerabilities (
+	var vulnSchema string
-					id SERIAL PRIMARY KEY,
+	if db.dialect == DialectPostgres {
-					vuln_id TEXT NOT NULL,
+		vulnSchema = `
-					ecosystem TEXT NOT NULL,
+			CREATE TABLE vulnerabilities (
-					package_name TEXT NOT NULL,
+				id SERIAL PRIMARY KEY,
-					severity TEXT,
+				vuln_id TEXT NOT NULL,
-					summary TEXT,
+				ecosystem TEXT NOT NULL,
-					fixed_version TEXT,
+				package_name TEXT NOT NULL,
-					cvss_score REAL,
+				severity TEXT,
-					"references" TEXT,
+				summary TEXT,
-					fetched_at TIMESTAMP,
+				fixed_version TEXT,
-					created_at TIMESTAMP,
+				cvss_score REAL,
-					updated_at TIMESTAMP
+				"references" TEXT,
-				);
+				fetched_at TIMESTAMP,
-				CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
+				created_at TIMESTAMP,
-				CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
+				updated_at TIMESTAMP
-			`
+			);
-		} else {
+			CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
-			vulnSchema = `
+			CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
-				CREATE TABLE vulnerabilities (
+		`
-					id INTEGER PRIMARY KEY,
+	} else {
-					vuln_id TEXT NOT NULL,
+		vulnSchema = `
-					ecosystem TEXT NOT NULL,
+			CREATE TABLE vulnerabilities (
-					package_name TEXT NOT NULL,
+				id INTEGER PRIMARY KEY,
-					severity TEXT,
+				vuln_id TEXT NOT NULL,
-					summary TEXT,
+				ecosystem TEXT NOT NULL,
-					fixed_version TEXT,
+				package_name TEXT NOT NULL,
-					cvss_score REAL,
+				severity TEXT,
-					"references" TEXT,
+				summary TEXT,
-					fetched_at DATETIME,
+				fixed_version TEXT,
-					created_at DATETIME,
+				cvss_score REAL,
-					updated_at DATETIME
+				"references" TEXT,
-				);
+				fetched_at DATETIME,
-				CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
+				created_at DATETIME,
-				CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
+				updated_at DATETIME
-			`
+			);
-		}
+			CREATE UNIQUE INDEX IF NOT EXISTS idx_vulns_id_pkg ON vulnerabilities(vuln_id, ecosystem, package_name);
-		if _, err := db.Exec(vulnSchema); err != nil {
+			CREATE INDEX IF NOT EXISTS idx_vulns_ecosystem_pkg ON vulnerabilities(ecosystem, package_name);
-			return fmt.Errorf("creating vulnerabilities table: %w", err)
+		`
-		}
+	}
+	if _, err := db.Exec(vulnSchema); err != nil {
+		return fmt.Errorf("creating vulnerabilities table: %w", err)
 	}
 
 	return nil
 }
+
+func migrateEnsureMetadataCacheTable(db *DB) error {
+	return db.EnsureMetadataCacheTable()
+}
+
+// EnsureMetadataCacheTable creates the metadata_cache table if it doesn't exist.
+func (db *DB) EnsureMetadataCacheTable() error {
+	has, err := db.HasTable("metadata_cache")
+	if err != nil {
+		return fmt.Errorf("checking metadata_cache table: %w", err)
+	}
+	if has {
+		return nil
+	}
+
+	var schema string
+	if db.dialect == DialectPostgres {
+		schema = `
+			CREATE TABLE metadata_cache (
+				id SERIAL PRIMARY KEY,
+				ecosystem TEXT NOT NULL,
+				name TEXT NOT NULL,
+				storage_path TEXT NOT NULL,
+				etag TEXT,
+				content_type TEXT,
+				size BIGINT,
+				last_modified TIMESTAMP,
+				fetched_at TIMESTAMP,
+				created_at TIMESTAMP,
+				updated_at TIMESTAMP
+			);
+			CREATE UNIQUE INDEX IF NOT EXISTS idx_metadata_eco_name ON metadata_cache(ecosystem, name);
+		`
+	} else {
+		schema = `
+			CREATE TABLE metadata_cache (
+				id INTEGER PRIMARY KEY,
+				ecosystem TEXT NOT NULL,
+				name TEXT NOT NULL,
+				storage_path TEXT NOT NULL,
+				etag TEXT,
+				content_type TEXT,
+				size INTEGER,
+				last_modified DATETIME,
+				fetched_at DATETIME,
+				created_at DATETIME,
+				updated_at DATETIME
+			);
+			CREATE UNIQUE INDEX IF NOT EXISTS idx_metadata_eco_name ON metadata_cache(ecosystem, name);
+		`
+	}
+	if _, err := db.Exec(schema); err != nil {
+		return fmt.Errorf("creating metadata_cache table: %w", err)
+	}
+	return nil
+}

internal/database/types.go

@@ -76,18 +76,33 @@ func (a *Artifact) IsCached() bool {
 	return a.StoragePath.Valid && a.FetchedAt.Valid
 }
 
-// Vulnerability represents a cached vulnerability record.
+// MetadataCacheEntry represents a cached metadata blob for offline serving.
-type Vulnerability struct {
+type MetadataCacheEntry struct {
 	ID           int64          `db:"id" json:"id"`
-	VulnID       string         `db:"vuln_id" json:"vuln_id"`
 	Ecosystem    string         `db:"ecosystem" json:"ecosystem"`
-	PackageName  string         `db:"package_name" json:"package_name"`
+	Name         string         `db:"name" json:"name"`
-	Severity     sql.NullString `db:"severity" json:"severity,omitempty"`
+	StoragePath  string         `db:"storage_path" json:"storage_path"`
-	Summary      sql.NullString `db:"summary" json:"summary,omitempty"`
+	ETag         sql.NullString `db:"etag" json:"etag,omitempty"`
-	FixedVersion sql.NullString `db:"fixed_version" json:"fixed_version,omitempty"`
+	ContentType  sql.NullString `db:"content_type" json:"content_type,omitempty"`
-	CVSSScore    sql.NullFloat64 `db:"cvss_score" json:"cvss_score,omitempty"`
+	Size         sql.NullInt64  `db:"size" json:"size,omitempty"`
-	References   sql.NullString `db:"references" json:"references,omitempty"`
+	LastModified sql.NullTime   `db:"last_modified" json:"last_modified,omitempty"`
 	FetchedAt    sql.NullTime   `db:"fetched_at" json:"fetched_at,omitempty"`
 	CreatedAt    time.Time      `db:"created_at" json:"created_at"`
 	UpdatedAt    time.Time      `db:"updated_at" json:"updated_at"`
 }
+
+// Vulnerability represents a cached vulnerability record.
+type Vulnerability struct {
+	ID           int64           `db:"id" json:"id"`
+	VulnID       string          `db:"vuln_id" json:"vuln_id"`
+	Ecosystem    string          `db:"ecosystem" json:"ecosystem"`
+	PackageName  string          `db:"package_name" json:"package_name"`
+	Severity     sql.NullString  `db:"severity" json:"severity,omitempty"`
+	Summary      sql.NullString  `db:"summary" json:"summary,omitempty"`
+	FixedVersion sql.NullString  `db:"fixed_version" json:"fixed_version,omitempty"`
+	CVSSScore    sql.NullFloat64 `db:"cvss_score" json:"cvss_score,omitempty"`
+	References   sql.NullString  `db:"references" json:"references,omitempty"`
+	FetchedAt    sql.NullTime    `db:"fetched_at" json:"fetched_at,omitempty"`
+	CreatedAt    time.Time       `db:"created_at" json:"created_at"`
+	UpdatedAt    time.Time       `db:"updated_at" json:"updated_at"`
+}

internal/handler/cargo.go

@@ -3,8 +3,8 @@ package handler
 import (
 	"bufio"
 	"encoding/json"
+	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"strings"
 	"time"
@@ -88,44 +88,27 @@ func (h *CargoHandler) handleIndex(w http.ResponseWriter, r *http.Request) {
 
 	h.proxy.Logger.Info("cargo index request", "crate", name)
 
-	// Build the index path
 	indexPath := h.buildIndexPath(name)
 	upstreamURL := fmt.Sprintf("%s/%s", h.indexURL, indexPath)
 
-	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, upstreamURL, nil)
+	body, contentType, err := h.proxy.FetchOrCacheMetadata(r.Context(), "cargo", name, upstreamURL, "text/plain")
-	if err != nil {
-		http.Error(w, "internal error", http.StatusInternalServerError)
-		return
-	}
-
-	resp, err := h.proxy.HTTPClient.Do(req)
 	if err != nil {
+		if errors.Is(err, ErrUpstreamNotFound) {
+			http.Error(w, "not found", http.StatusNotFound)
+			return
+		}
 		h.proxy.Logger.Error("failed to fetch upstream index", "error", err)
 		http.Error(w, "failed to fetch from upstream", http.StatusBadGateway)
 		return
 	}
-	defer func() { _ = resp.Body.Close() }()
 
-	if resp.StatusCode == http.StatusNotFound {
+	if contentType == "" {
-		http.Error(w, "not found", http.StatusNotFound)
+		contentType = "text/plain; charset=utf-8"
-		return
-	}
-	if resp.StatusCode != http.StatusOK {
-		http.Error(w, fmt.Sprintf("upstream returned %d", resp.StatusCode), http.StatusBadGateway)
-		return
 	}
 
-	// Copy headers and body
+	w.Header().Set("Content-Type", contentType)
-	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
-	if etag := resp.Header.Get("ETag"); etag != "" {
+	h.applyCooldownFiltering(w, body)
-		w.Header().Set("ETag", etag)
-	}
-	if lastMod := resp.Header.Get("Last-Modified"); lastMod != "" {
-		w.Header().Set("Last-Modified", lastMod)
-	}
-
-	h.applyCooldownFiltering(w, resp.Body)
-
 }
 
 type crateIndexEntry struct {
@@ -134,56 +117,45 @@ type crateIndexEntry struct {
 	PublishTime string `json:"pubtime,omitempty"`
 }
 
-func (h *CargoHandler) applyCooldownFiltering(downstreamResponse io.Writer, upstreamBody io.Reader) {
+func (h *CargoHandler) applyCooldownFiltering(downstreamResponse http.ResponseWriter, body []byte) {
 	if h.proxy.Cooldown == nil || !h.proxy.Cooldown.Enabled() {
-		// not using cooldowns, just copy the upstream to the downstream
+		_, _ = downstreamResponse.Write(body)
-		_, _ = io.Copy(downstreamResponse, upstreamBody)
 		return
 	}
 
-	// create a scanner on the body of the http response
+	scanner := bufio.NewScanner(strings.NewReader(string(body)))
-	requestScanner := bufio.NewScanner(upstreamBody)
 
-	// the response is newline-delimited JSON, loop through each line
+	for scanner.Scan() {
-	for requestScanner.Scan() {
+		line := scanner.Text()
-		line := requestScanner.Text()
 
-		// decode the line
 		var crate crateIndexEntry
 		err := json.Unmarshal([]byte(line), &crate)
 
 		if err != nil {
-			// if there is an error parsing this line then exclude it and move to the next entry
 			h.proxy.Logger.Error("failed to parse json entry in index", "error", err)
 			continue
 		}
 
-		// parse publish time
 		publishedAt, err := time.Parse(time.RFC3339, crate.PublishTime)
 
 		if crate.PublishTime == "" || err != nil {
-			// publish time is empty/missing/invalid, presumably was published before pubtime was added as a field
-			// write line to response
 			_, _ = downstreamResponse.Write([]byte(line + "\n"))
 			continue
 		}
 
-		// make PURL
 		cratePURL := purl.MakePURLString("cargo", crate.Name, "")
 
 		if !h.proxy.Cooldown.IsAllowed("cargo", cratePURL, publishedAt) {
-			// crate is not allowed, move to next crate
 			h.proxy.Logger.Info("cooldown: filtering cargo version",
 				"crate", crate.Name, "version", crate.Version,
 				"published", crate.PublishTime)
 			continue
 		}
 
-		// crate passes, write to response
 		_, _ = downstreamResponse.Write([]byte(line + "\n"))
 	}
 
-	if err := requestScanner.Err(); err != nil {
+	if err := scanner.Err(); err != nil {
 		h.proxy.Logger.Error("error reading index response", "error", err)
 	}
 }