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at-container-registry/docs/HOLD_XRPC_ENDPOINTS.md
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Evan JarrettandClaude Fable 5.1 f4343d7956 appview: upload small blobs with one presigned PUT, and verify every digest
Every blob went through the multipart machinery: an S3 multipart started
on Docker's initial POST, a hold round trip per part, and a complete on
the hold that finished the multipart, HEADed the temp object, copied it
to its final key, and deleted the temp. For a 2KB config blob that was
three hold calls and six S3 operations. On production data 86% of
distinct layers and every config blob fit in a 16MB buffer, and 49% of
image manifests have no layer larger than that.

The writer now buffers up to 16MB (also the multipart part size) and
makes no hold call until it has to. A blob that never overflows the
buffer is written at Commit with a single presigned PUT to its final
key, via the hold's existing method=PUT presign; the multipart only
starts on the first flush. The hold's completeUpload does nothing the
direct path skips: quota, layer records, stats and scan dispatch all
hang off notifyManifest, which is unchanged.

The buffer starts empty and grows on demand, with the doubling capped so
capacity never overshoots 16MB: a config blob costs kilobytes, and only
layers that approach the threshold fill it.

Bytes are hashed as they arrive. Commit compares the computed sha256 to
the digest the client claimed before any network call, and returns
DIGEST_INVALID on mismatch, aborting a multipart if one was started.
Previously nothing verified the content, so a pusher could store wrong
bytes under a digest in the shared content-addressed space.

Tests observe request counts on a fake hold and fake S3 rather than
return values. The growth test streams in 24KB chunks because
power-of-two chunks land on 16MB by luck and hid an earlier weaker guard.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Yf1ZVA7sXYhQNb9tCo1m5
2026-09-09 09:50:08 -05:00

9.5 KiB

Hold Service XRPC Endpoints

This document lists all XRPC endpoints implemented in the Hold service (pkg/hold/).

PDS Endpoints (pkg/hold/pds/xrpc.go)

Public (No Auth Required)

Endpoint Method Description
/xrpc/_health GET Health check
/xrpc/com.atproto.server.describeServer GET Server metadata
/xrpc/com.atproto.repo.describeRepo GET Repository information
/xrpc/com.atproto.repo.getRecord GET Retrieve a single record
/xrpc/com.atproto.repo.listRecords GET List records in a collection (paginated)
/xrpc/com.atproto.sync.listBlobs GET List blob CIDs for an account
/xrpc/com.atproto.sync.listRepos GET List all repositories
/xrpc/com.atproto.sync.getRecord GET Get record as CAR file
/xrpc/com.atproto.sync.getRepo GET Full repository as CAR file
/xrpc/com.atproto.sync.getRepoStatus GET Repository hosting status
/xrpc/com.atproto.sync.getLatestCommit GET Current commit CID and revision
/xrpc/com.atproto.sync.subscribeRepos GET WebSocket firehose
/xrpc/com.atproto.identity.resolveHandle GET Resolve handle to DID
/xrpc/app.bsky.actor.getProfile GET Get actor profile
/xrpc/app.bsky.actor.getProfiles GET Get multiple profiles
/xrpc/io.atcr.hold.listTiers GET List hold's available tiers with quotas and features
/.well-known/did.json GET DID document
/.well-known/atproto-did GET DID for handle resolution

Conditional Auth (based on captain.public)

Endpoint Method Description
/xrpc/com.atproto.sync.getBlob GET/HEAD Get blob (routes OCI vs ATProto)

getBlob response shape

The endpoint routes on the cid parameter and answers differently per branch.

ATProto blob (cid is a CID): 307 redirect to a presigned URL.

OCI blob (cid starts with sha256:): JSON.

{
  "url": "https://s3.example.com/...?X-Amz-Signature=...",
  "size": 27129344
}
Field Type Notes
url string Presigned URL for the requested method (GET, HEAD or PUT). Always present on a 200.
size int64 Blob size in bytes. Present on GET and HEAD only, and omitted when the size could not be resolved.

size lets the AppView build an OCI descriptor without a second round trip: ProxyBlobStore.Stat used to fetch a presigned HEAD URL here and then HEAD it against S3 purely to read Content-Length. It is resolved from the hold's records index (any layer with an io.atcr.hold.layer record) and falls back to a HeadObject (image config blobs, and layers whose manifest notification has not landed yet).

The field is additive. A client that reads only url behaves exactly as before, and an AppView that gets no size falls back to HEADing the presigned URL. size is never sent for a PUT presign: the object does not exist yet.

A method=PUT presign is a write capability (gated on blob:write, same as the multipart endpoints) and is how the AppView uploads a blob small enough to fit in its 16MB buffer: one presigned PUT to the blob's final sha256: key, instead of initiateUpload plus part URLs plus completeUpload plus the server side copy out of the temp key. The URL is signed with Content-Type: application/octet-stream, so the PUT has to carry that header or S3 rejects the signature.

On GET and HEAD, a blob that is not in storage is answered with 404 and a JSON error body instead of a presigned URL:

{
  "error": "BlobUnknown",
  "message": "blob not found"
}

Owner/Crew Admin Required

Endpoint Method Description
/xrpc/com.atproto.repo.deleteRecord POST Delete a record
/xrpc/com.atproto.repo.uploadBlob POST Upload ATProto blob

Inline Auth (per-manifest caller check)

/xrpc/io.atcr.hold.purgeManifest (POST) does not use a router middleware. Auth is validated inline by ValidateManifestPurger, which accepts either a Bearer service token or a DPoP token, then checks the caller's role:

  • Hold captain (any manifest)
  • Crew member with crew:admin permission (any manifest)
  • Crew member whose DID matches the manifest URI's DID (own manifests only)

Idempotent. Does not delete S3 blobs — GC handles those.

Auth Required (Service Token)

The requireAuth middleware validates Bearer service tokens only. requestCrew additionally accepts DPoP tokens when called directly (the handler falls back to ValidateDPoPRequest if no user is in context).

Endpoint Method Description
/xrpc/io.atcr.hold.requestCrew POST Request crew membership (service token or DPoP)
/xrpc/io.atcr.hold.exportUserData GET GDPR data export (returns user's records; service token only)
/xrpc/io.atcr.hold.deleteUserData DELETE GDPR data deletion (deletes crew, layer, and stats records; service token only)

Appview Token Required

/xrpc/io.atcr.hold.updateCrewTier (POST) validates the caller inline via ValidateAppviewToken. Returns 503 if the appview DID is not configured on the hold, or 401 on token validation failure.

Endpoint Method Description
/xrpc/io.atcr.hold.updateCrewTier POST Update a crew member's tier (appview JWT, ES256)

Scanner WebSocket

Endpoint Method Description
/xrpc/io.atcr.hold.subscribeScanJobs GET (WebSocket) Scanner job subscription. Auth via ?secret= query param or X-Scanner-Secret header (shared secret). Supports ?cursor= for backfill, ?workers= to declare how many scans the process runs at once (default 1), and ?instance= to declare a stable process identity so a reconnecting scanner resumes its own in-flight jobs.

OCI Multipart Upload Endpoints (pkg/hold/oci/xrpc.go)

All require blob:write permission via service token:

Endpoint Method Description
/xrpc/io.atcr.hold.initiateUpload POST Start multipart upload
/xrpc/io.atcr.hold.getPartUploadUrl POST Get presigned S3 URL for a part; the client PUTs the part bytes directly to S3
/xrpc/io.atcr.hold.completeUpload POST Finalize multipart upload
/xrpc/io.atcr.hold.abortUpload POST Cancel multipart upload
/xrpc/io.atcr.hold.notifyManifest POST Notify manifest push (creates layer records + optional Bluesky post)

ATCR Hold-Specific Endpoints (io.atcr.hold.*)

Endpoint Method Auth Description
/xrpc/io.atcr.hold.initiateUpload POST blob:write Start multipart upload
/xrpc/io.atcr.hold.getPartUploadUrl POST blob:write Get presigned S3 URL for a part; client PUTs bytes directly to S3
/xrpc/io.atcr.hold.completeUpload POST blob:write Finalize multipart upload
/xrpc/io.atcr.hold.abortUpload POST blob:write Cancel multipart upload
/xrpc/io.atcr.hold.notifyManifest POST blob:write Notify manifest push/pull (creates layer records, increments stats, optional Bluesky post)
/xrpc/io.atcr.hold.requestCrew POST service token or DPoP Request crew membership
/xrpc/io.atcr.hold.exportUserData GET service token GDPR data export
/xrpc/io.atcr.hold.deleteUserData DELETE service token GDPR data deletion (crew, layer, stats records)
/xrpc/io.atcr.hold.getQuota GET none Get user quota info
/xrpc/io.atcr.hold.getLayersForManifest GET none Get layer records for a manifest AT-URI
/xrpc/io.atcr.hold.image.getConfig GET none Get OCI image config record for a manifest digest
/xrpc/io.atcr.hold.purgeManifest POST inline (service token or DPoP; captain, crew:admin, or manifest owner) Purge layer/scan/image-config records for a single manifest URI. Called by appview on UI delete; called internally on takedown receipt. Does not delete S3 blobs (GC handles those).
/xrpc/io.atcr.hold.listTiers GET none List hold's available tiers with quotas and features (scanOnPush)
/xrpc/io.atcr.hold.updateCrewTier POST appview token (ES256 JWT; 503 if appview DID not configured) Update crew member's tier
/xrpc/io.atcr.hold.subscribeScanJobs GET (WebSocket) shared secret (?secret= or X-Scanner-Secret) Scanner job subscription; supports ?cursor= for backfill, ?workers= for concurrency, ?instance= for reconnect resumption

Standard ATProto Endpoints (excluding io.atcr.hold.*)

Endpoint
/xrpc/_health
/xrpc/com.atproto.server.describeServer
/xrpc/com.atproto.repo.describeRepo
/xrpc/com.atproto.repo.getRecord
/xrpc/com.atproto.repo.listRecords
/xrpc/com.atproto.repo.deleteRecord
/xrpc/com.atproto.repo.uploadBlob
/xrpc/com.atproto.sync.listBlobs
/xrpc/com.atproto.sync.listRepos
/xrpc/com.atproto.sync.getRecord
/xrpc/com.atproto.sync.getRepo
/xrpc/com.atproto.sync.getRepoStatus
/xrpc/com.atproto.sync.getLatestCommit
/xrpc/com.atproto.sync.getBlob
/xrpc/com.atproto.sync.subscribeRepos
/xrpc/com.atproto.identity.resolveHandle
/xrpc/app.bsky.actor.getProfile
/xrpc/app.bsky.actor.getProfiles
/.well-known/did.json
/.well-known/atproto-did

See Also

  • DIRECT_HOLD_ACCESS.md - How to call hold endpoints directly without AppView (app passwords, curl examples)
  • BYOS.md - Bring Your Own Storage architecture
  • OAUTH.md - OAuth + DPoP authentication details