Polish pass hardening the queue and closing plan gaps.
- Task state machine gains `running`: the first heartbeat moves a task from
leased to running (migrations 0006/0007 add the enum value and extend the
lease-integrity check). verifyLease, ExpireLease, the reaper SQL, and job
progress all treat leased and running alike.
- Worker liveness: a heartbeat from a registered worker (UUID worker_id) bumps
its last_heartbeat_at online; a second background reaper marks workers offline
after WORKER_OFFLINE_AFTER of silence (RunReaper generalized to RunPeriodic).
- Request-size limits: JSON bodies capped at 1 MiB; dataset/artifact uploads
capped at MAX_UPLOAD_BYTES (default 1 GiB) via http.MaxBytesReader.
- Tests cover the running transition, liveness + offline reaper (unit over
memstore and integration over Postgres).
The coordinator can now ingest a dataset itself, not only accept client-supplied
chunk URIs.
- internal/chunk: a deterministic, generic TSV row splitter — repeats the header
per shard, buffers one shard at a time, rejects header-only input. Unit-tested.
- POST /jobs/upload (multipart): streams the dataset into an input artifact,
splits it into shard artifacts, and creates one shard task per shard, all in
one transaction; blobs are cleaned up if the transaction fails.
- GET /tasks/{id}/input streams a task's input shard back to the worker.
- domain: NewUploadedJob, NewShardTask, Task/Job.InputArtifactID; a shard task's
input is an artifact, not a URI. Claim response nests input:{uri,sha256} per
the contract, with uri = /tasks/{id}/input for shards.
- migration 0005 makes input_uri nullable and adds a has-input check.
- The existing URI-based POST /jobs path is untouched; both coexist.
Task results are now coordinator-owned artifacts end to end.
- domain.Task carries ResultArtifactID instead of ResultURI/ResultSHA256;
CompleteWith and its idempotency key are keyed on the artifact id.
- CompleteTask verifies the referenced artifact was stored for this exact
task (rule 10): a worker cannot finish task B with task A's artifact, nor
name an id that isn't a partial_result. Mismatch → 409.
- POST /tasks/{id}/result takes {result:{artifact_id,...}}; ListResults and
ResultManifest follow.
- migration 0004 drops result_uri/result_sha256 and requires a completed task
to reference its result_artifact_id.
- smoke and requests.http exercise upload → complete-by-id → replay → conflict.
Adds the SciMesh coordinator: a durable task-queue server on PostgreSQL
that owns all database access, with workers reaching it over HTTP only.
Structured as a modular monolith following Clean Architecture:
domain entities and their invariants, no I/O
usecase business operations + repository/clock ports
transport HTTP handlers, DTOs, auth, error mapping
storage PostgreSQL repositories, transactions carried in context
infra config, pool, clock, server, lease reaper
Dependencies point strictly inward; domain imports nothing from the module.
Working: layer wiring, routing, shared-token auth, access logging, request
IDs, domain-error to status-code mapping, transactional boundaries,
graceful shutdown (HTTP drain -> reaper stop -> pool close), migrations,
and a Compose stack starting Postgres -> migrations -> coordinator.
The domain is complete and covered by unit tests that need no database:
lease ownership, stale attempts, idempotent result replay, retry budgets,
and lease expiry.
Repository methods are stubs returning ErrNotImplemented (HTTP 501). The
SQL for atomic claiming (FOR UPDATE SKIP LOCKED) and for lease expiry is
written and ready to wire up.
See coordinator/ARCHITECTURE.md for the layer map and a request traced
through every layer.
Emil