ElasticBLAST Resource Plane (detail)

Re-verified 2026-09-16 against api/main.py, api/celery_app.py, and api/run_celery_workers.py.

The web app is the control surface for the infrastructure used by ElasticBLAST. Bounded reads and small wizard operations may complete inside a FastAPI request. Long-running or retryable work is implemented as Celery tasks under api/tasks/, queued through the in-revision Redis sidecar, and executed by the worker sidecar. The API returns a task or operation id; the SPA polls the corresponding status route and also receives job-change invalidations over SSE.

Request Versus Task Boundary

• api/routes/arm.py, api/routes/resources.py, and the monitor packages own bounded discovery, response shaping, and small idempotent setup calls.
• Routes enqueue any operation that can exceed an HTTP request budget and return 202 Accepted with durable identifiers.
• Azure SDK calls stay in api/services/; Kubernetes calls use the direct api.services.k8s client; CLI-only work uses the authenticated terminal sidecar exec channel.

Task Families And Queues

Task family	Main responsibilities	Queue / worker owner
api.tasks.azure.*	AKS provision/start/scale/stop/delete, runtime RBAC, idle auto-stop, and observability setup	azure on worker-main; periodic reconciliation may target reconcile
api.tasks.acr.*	Build the pinned runtime and OpenAPI images through ACR Tasks	acr on worker-main
api.tasks.storage.*	Prepare/update databases, warm node caches, build/retain order oracles, purge aged results, and repair database state	interactive work on storage; periodic repair on reconcile
api.tasks.blast.*	Submit/cancel/status, split merge, retry, runtime-metric backfill, and job reconciliation	blast on worker-main; periodic repair on reconcile
api.tasks.blast.artifacts.*	Capture and reconcile terminal Kubernetes artifacts after a run	blast-artifacts on worker-artifacts
api.tasks.openapi.*	Deploy/rebuild OpenAPI, configure public HTTPS, and reconcile its runtime endpoint	interactive work on azure; periodic repair on reconcile
api.tasks.servicebus.*	Drain requests, publish durable transitions, reconcile DLQ responses, and emit health	servicebus on worker-servicebus
api.tasks.upgrade.*	Check releases, build and deploy revisions, rollback, and compact upgrade history	interactive work on default; periodic repair on reconcile
api.tasks.webhooks.*	Deliver configured terminal-job notifications	reconcile

The worker sidecar launches four isolated Celery parents: worker-main (default,acr,azure,blast,storage, concurrency 2), worker-reconcile (reconcile, concurrency 1), worker-servicebus (servicebus, concurrency 1), and worker-artifacts (blast-artifacts, concurrency 1). This prevents slow maintenance or external-message work from starving interactive operations.

Durable State Contract

Tasks must be idempotent, side-effect-tagged in their docstrings, and write progress checkpoints through api/services/state_repo.py. Redis is ephemeral: the durable authority for status, history, schedules, configuration, and recovery is Azure Table/Blob Storage. Beat reconcilers reconstruct work after a revision restart rather than trusting Celery result state.

Image tags must stay in sync with src/elastic_blast/constants.py in the sibling repository. Every image-building task reads the single IMAGE_TAGS mapping in api/services/image_tags.py; documentation should link that source instead of copying the current OpenAPI tag.