[simonchrz]

An image's page in the web UI (/ui/package/oci/{name}) lists only its cached blobs, by digest. A new release such as pihole/pihole:2026.11.0 can't be told apart from the image before it, and nothing shows which digest latest points at.

This adds a "Tags" section to that page:

• A pull by tag (a GET, or the HEAD Docker and containerd send first) and a scheduled mirror run record the digest the tag points at, in a new image_tags table (package_purl, tag, digest, seen_at, migration 025_add_image_tags).
• The time is when the upstream last confirmed the tag. A copy served stale during an outage doesn't move it, and an older sighting doesn't overwrite a newer one.
• Pulls by digest record no tag. Referrers and cosign tags (sha256-<hex>, .sig, .att, .sbom) are left out, since they don't name an image.
• The page lists up to 100 tags, the most recently seen first, with the digest and the time. Other ecosystems are unchanged.
• A blob's page (/ui/package/oci/{name}/{digest}) names, under Version Info, up to 100 tags whose cached image contains it, the most recently seen first. The page reads what each manifest references from image_manifests, the table Keep the blobs of the newest container images with keep_latest #702 added, and walks from the blob up to the tags: tags pointing at the blob, at a manifest that references it, or at an index listing such a manifest. Only what clients or mirror runs pulled is known.

Two things change in what #702 added, so the UI can read that table:

• Manifests are recorded whether or not keep_latest is set. Proxy.KeepLatestImages and keepLatestImages only gated the recording and are gone.
• The retention sweep keeps the records of the images a repository's tags point at, besides those of its newest keep_latest images. With keep_latest off it used to drop every record.

image_tags rows are never pruned. They are small: one per tag ever pulled. The docs (configuration.md, architecture.md) describe both tables as they now behave.

Tested with go test ./... and golangci-lint run ./... (0 issues). Removing the stale check, the referrers filter, the mirror hook, the walk up through indexes, the per-repository filter or the tagged images from the prune makes the tests fail. The database and server tests also ran against PostgreSQL.

Summary by CodeRabbit

• New Features
  • Container image pages now list tags by most recently seen, with each tag’s digest and upstream confirmation time.
  • Image version pages show tags associated with the cached content. These details appear only for container images.

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Walkthrough

The PR adds database storage for OCI image tags and manifest references. It records eligible tag sightings during container pulls and mirror runs, matches tags to cached image content, and displays tag information on OCI package and version pages.

Changes: OCI image tags

Layer / File(s)	Summary
Image-tag storage internal/database/image_tags.go, internal/database/schema.go, internal/database/image_tags_test.go	Adds storage for image tags and manifest references, with queries for ordered tags and tags matching a digest. Tests cover ordering, updates, limits, reference recording, and migrations.
Record tag sightings and manifest references internal/handler/container_image_tags.go, internal/handler/container_manifest.go, internal/handler/container_mirror.go, internal/handler/container_image_tags_test.go	Records eligible tag sightings from manifest responses and mirror runs. Records manifest references when the body matches its declared digest. Tests cover recording conditions and tag matches through manifests and their referenced content.
Show tags on package and version pages internal/server/dashboard.go, internal/server/server.go, internal/server/templates/pages/package_show.html, internal/server/templates/pages/version_show.html, internal/server/image_tags_ui_test.go, README.md	Loads tags for OCI package pages and tags matching cached image blobs. Displays tag digests and sighting times on package pages and matching tags on version pages. Tests cover OCI and non-OCI pages. The README describes the displayed information.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant ContainerClient
  participant ContainerManifest
  participant recordImageTag
  participant DB
  participant PackagePage
  participant VersionPage
  ContainerClient->>ContainerManifest: Request manifest by tag
  ContainerManifest->>recordImageTag: Pass reference and response state
  recordImageTag->>DB: Store eligible tag and digest
  PackagePage->>DB: Load ordered package tags
  DB-->>PackagePage: Return tag records
  VersionPage->>DB: Load tags matching the blob digest
  DB-->>VersionPage: Return matching tags

Loading

Possibly related PRs

• git-pkgs/proxy#702: Both PRs change manifest handling and mirror paths and add migrations to the same sequence.
• git-pkgs/proxy#679: The accepted digest formats affect the digest validation used when recording tag sightings.

Suggested reviewers: andrew, pinguinfuss

Merge Risk: Low · previous review 15d78

Blob pages for images served with SHA-512 manifests will not list their tags, although the tags are recorded. This is a narrow display gap with a one-line fix. Everything else in the change behaves as described.

Security architecture risk: Moderate · up to 15d78

The repository-scoped queries, digest checks, and atomic writes provide useful safeguards. However, manifest pulls now accumulate permanent database records outside the existing cache-size limit. Where users can pull images they publish to an allowed registry, this creates a shared-database resource-exhaustion risk.

Retained concerns

• Medium · security · inferred: New manifest-reference and tag records outlive cache eviction and are excluded from cache-size accounting. A publisher whose repository is reachable through the proxy can cause pulls of successive manifests or tags to accumulate permanent shared-database state. Large manifests also trigger a synchronous per-reference transaction on the shared writer before the response is sent. Existing integrity checks establish content identity, not a storage or work budget; the 100-tag display limit does not constrain writes. This introduces a resource-containment risk beyond the base's evictable manifest cache, potentially affecting other users and ecosystems sharing the database.

Security review details

Security Blast Radius

• inferred — The relevant attack requires access to the pull interface and control over content published in a repository on an allowed registry, or inducing a mirror of that content. Registry selection remains configuration-bound. Accumulated records use the shared database rather than repository-isolated storage; SQLite reference transactions can occupy its single writer and affect unrelated writes.

Security Findings and Attack Paths

• inferred — Successive attacker-published manifests can pass content-hash verification and create new permanent reference sets through ordinary pulls. Evicting their cached documents does not reclaim these new rows, and changing a single tag repeatedly can grow reference history without increasing tag cardinality. This supports the resource-containment concern, not a demonstrated outage or authorization bypass.

Trust Boundaries and Controls

• observed — SQL values are parameterized, and every tag-to-content query branch is scoped to the same package PURL, including the parent-child join. Readers use the package already resolved by the existing page handler. This preserves repository scoping, although the actual audience of those pages depends on deployment access rules.

Resilience and Maintainability Implications

• observed — Countercontrols include the existing metadata byte limit, transactional reference insertion, unique keys, and skipping already-recorded reference sets. Mirror tag sightings occur only after a successful walk and are skipped on its stale fallback or detected concurrent tag movement. These protect integrity and repeated work, but do not bound lifetime storage across distinct manifests.

Hardening Proposals

• proposed — Give the new metadata an explicit resource lifecycle: enforce reference-count and aggregate storage budgets, reclaim unreachable or expired records, and bound synchronous recording work so optional UI metadata cannot monopolize the shared writer. These are proposed controls, not existing guarantees.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title "List a container image's tags on its page" matches the main change. The PR adds tag tracking and manifest-reference storage, and shows each image's tags on the package page (and tags contai…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.

Full details: Title check

Explanation

The title "List a container image's tags on its page" matches the main change. The PR adds tag tracking and manifest-reference storage, and shows each image's tags on the package page (and tags containing a blob on the version page). The title names the primary user-visible change and omits the tracking and migration details, which is acceptable.

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Inline comments:
Review comments at @internal/handler/container_image_tags.go:
- Around line 25-26: Update the manifest-only sighting flow around
canonicalPackagePURL and RecordImageTag so a package row exists before the tag
is recorded. Reuse the repository’s established package-creation path and
preserve the existing tag-recording behavior, including error handling.

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• internal/database/image_tags.go
• internal/database/image_tags_test.go
• internal/database/schema.go
• internal/handler/container_image_tags.go
• internal/handler/container_image_tags_test.go
• internal/handler/container_manifest.go
• internal/handler/container_mirror.go
• internal/server/dashboard.go
• internal/server/image_tags_ui_test.go
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Prompt to fix all issues

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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
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Inline comments:
Review comments at @internal/server/server.go:
- Line 1323: Update the tag lookup in the version-page flow around ImageTags to
apply maxImageTagsShown to tags that match the blob, not to the newest candidate
tags. Inspect candidates in batches until enough matches are found or candidates
are exhausted, and preserve the existing matching and ordering behavior.

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• internal/server/image_tags_ui_test.go
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Prompt to fix all issues

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Inline comments:
Review comments at @internal/server/server.go:
- Line 1237: Update ImageTagsContaining and the maxImageTagsSearched approach to
avoid sequentially reading up to 1,000 manifests for each page request. Use a
reverse index or another strategy that bounds request-time database and storage
I/O while still finding older matching tags; do not solve the cost by excluding
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Review comments at @internal/handler/container_image_tags.go:
- Line 39: Update the manifest validation condition near the `h.proxy.DB` nil
check to use `verifyDigest` with `manifest.contentDigest` and `manifest.body`
instead of hashing only with SHA-256. Preserve the nil-database guard and skip
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[milas]

(not a maintainer)

This seems correct / reasonable to me behavior-wise. I also applied the PR changes to my testing instance - tags are populating as expected.

[simonchrz]

Merged main after #702 went in (8c0919f) and reworked this to use its table instead of adding a second one for the same data.

• image_manifest_references is gone. A blob's page reads the references from image_manifests.
• image_tags stays, as migration 025.
• For the UI to have something to read, manifests are now recorded whether or not keep_latest is set, and the retention sweep keeps the records of what a repository's tags point at. Proxy.KeepLatestImages and keepLatestImages only gated the recording, so I removed them with their tests.

That last point changes behaviour #702 settled on, so say if you'd rather keep the recording gated; the blob page would then name tags only with keep_latest set.

[andrew]

Thanks for reworking this onto the image_manifests table, the tag list is a good addition. On your question: keep the recording ungated, so a blob's page names its tags on every install. That needs the two changes below before it can merge, because the records are currently only bounded when a retention rule is set.

image_manifests is never pruned without a retention rule. recordImageManifest now records for everyone, but the only prune is pruneImageRecords, called from sweepRetention after the rules.MinPositive() == 0 return, and startRetentionLoop returns before its first sweep in that case too. On a default config the table gets one row per manifest ever served and nothing deletes them. ImageTagsContaining then loads every image_manifests and image_tags row of the repository on each blob page view, so the page slows down as the table grows. Please run pruneImageRecords on its own tick, outside the retention gate, with a test that it runs with no retention rule configured.

image_tags needs a prune as well. PruneImageManifests keeps everything any tag has ever pointed at and tags are never removed, so a repository with per-commit tags keeps every manifest row even when the sweep runs. All of those digests also go into one NOT IN (?) list, which used to be bounded by keep_latest. Past about 32k digests that exceeds SQLite's bind limit and the prune fails on every sweep with only a warning. Please drop tags the upstream has not confirmed for some time in the same sweep (pick a default you think is sensible), and batch the delete.

Three smaller things:

• recordImageTag runs an upsert on every tag GET and HEAD, including fresh cache hits where seen_at has not moved. SQLite has one writer connection, so every cached pull and every Watchtower-style HEAD now queues behind it before the response is written. recordImageManifest reads first and skips the write; please do the same here and return when the digest and time are unchanged.
• The manifest cache is keyed per Accept, so a client that accepts no index is served one platform's manifest for a tag, and RecordImageTag then overwrites the index digest with it. The tag table shows a platform digest and blobs of the other platforms lose the tag on their page. newestImages already treats this as the same image for retention. When the stored digest's refs include the incoming digest, only move seen_at, with a test.
• package_show.html renders Tags ({{len .Tags}}), which reads "Tags (100)" for a repository with 500. Drop the count or say it is the latest 100.

[simonchrz]

Thanks, kept the recording ungated. All five points are in 7b36b5d.

Pruning without retention. startImageRecordPruning runs pruneImageRecords once at startup and then hourly, outside the retention gate and under its own job lock, with keep_latest when one is set and 0 otherwise. sweepRetention no longer calls it. TestImageRecordPruningRunsWithoutRetention starts it on a server with no retention rule and checks the untagged manifest and the stale tag go.

Tags. PruneImageTags drops tags the upstream hasn't confirmed for 90 days (imageTagMaxAge), in the same pass and before the manifests, so what tags hold is bounded too. PruneImageManifests no longer builds a NOT IN list: it reads the repository's old digests, leaves out the kept ones in Go, and deletes the rest by name in batches of 500 (TestPruneImageManifestsInBatches lowers the batch to 2).

Smaller:

• recordImageTag reads the tag first and returns unless the upstream confirmed it later than stored. TestContainerCachedPullWritesNoTag counts insert attempts with a trigger over three GETs and HEADs of a fresh tag: one write.
• When the stored digest's refs include the incoming one, only seen_at moves (TouchImageTag). TestContainerPlatformManifestKeepsTheTagsIndex covers that, and that a digest the stored one doesn't reference still replaces it.
• The heading is now just "Tags", and the line below it says it lists up to 100 of the most recently seen.

The docs say the prune runs hourly with or without a retention rule, and that tags not pulled for 90 days go.