Development¶

make test               # unit tests, no network
make build              # -> bin/pier
make test-integration   # e2e: needs PIER_TEST_S3_ENDPOINT (S3Mock/rclone serve s3)

Integration test:

# start an S3-compatible store (rclone serve s3 works too):
#   docker run --rm -p 9090:9090 adobe/s3mock
PIER_TEST_S3_ENDPOINT=http://127.0.0.1:9090 \
PIER_TEST_S3_USER=testuser PIER_TEST_S3_PASS=testpass \
PIER_TEST_S3_BUCKET=pier-integration \
  go test -tags integration ./test/integration

Design decisions¶

• Plugin-maintained metadata is last-writer-wins. The deploy plugin's read-modify-write spans separate GET and PUT requests, which Pier cannot serialize, so concurrent deploys of different versions of the same GAV resolve last-writer-wins on the plugin-maintained document. Pier does not merge concurrent plugin writes. It does serialize its own read-modify-write — artifact PUT
• metadata invalidation, metadata synthesis, and plugin metadata PUTs — per GAV under an in-process lock, relying on S3's consistent read-after-write. Pier does not track metadata written directly to S3 (bypassing Pier) — only Pier-mediated PUTs trigger the synthesis invalidation.
• In-process per-GAV serialization, no cross-instance coordination. The per-GAV locks are process-local: simple, at a cost. With multiple replicas, Pier does not serialize concurrent operations on the same GAV across instances. The next artifact PUT for the GAV heals a bounded stale-document window.
• Single repository root. One flat repository per instance; the namespace is the group id, with reserved_groups splitting internal uploads from the pull-through cache. No named repositories.
• DELETE removes one object. No delete by prefix: bulk removal (a version, a group, a stale cached prefix) is an operator action on S3 — lifecycle rules, aws s3 rm, rclone — not a repository operation.