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
- diff view gains a Packages tab with added/removed/changed/unchanged
package tables and purl-derived type/license/upstream links
- captain records verified against the DID's atcr_hold service before
caching (processor + batch backfill), preventing forged holds
- fix empty-handle updates clobbering cached handles and colliding on
the UNIQUE constraint
- move fillPrevCIDs into repo.go; DirectRepoOperator is now canonical,
repomgr kept as a test oracle
- surface read-only crew status in hold selector
- reconcile docs
Evan JarrettandClaude Fable 5.1