Scriberr/devnotes/engine-worker-sprints.md

Sprint Run: Engine Worker Integration

Run ID: EWI

Status: planning only. Do not implement code from this document until the user explicitly starts an implementation sprint.

Scope

This sprint run implements devnotes/engine-worker-integration-spec.md end to end: local Go engine integration, durable transcription workers, canonical transcript JSON, executions/logs/models APIs, removal of legacy Python adapter startup paths, docs, and verification with fixture audio.

The work should stay backend-first. Frontend changes are out of scope unless an API contract change makes the current UI unable to compile or use the canonical endpoints.

Engineering Rules

• Follow test-driven development: write the narrow failing tests first, implement, then refactor.
• Keep commits small and intentional. Each sprint should usually produce 2-5 commits, grouped by behavior:
  • tests that define the target behavior,
  • implementation,
  • cleanup/docs,
  • verification fixes.
• Do not mix unrelated cleanup into implementation commits.
• Keep the API layer thin. Handlers validate, map requests/responses, and call service interfaces.
• Keep SQLite as the source of truth. In-memory state may wake workers and cancel local jobs only.
• Do not leak local file paths, model cache paths, tokens, raw command output, or env-specific internals through API responses, logs endpoints, or SSE events.
• Preserve future multi-user scheduling hooks by carrying user_id through claim, execution, cancellation, and stats code.
• Prefer fake providers/processors for fast tests. Real engine tests must be opt-in and skipped cleanly when runtime/model dependencies are unavailable.
• Use test-audio/jfk.wav for fast real-path smoke tests. Use longer audio only for opt-in local performance checks.

Validation Baseline

Run these checks before and after each implementation sprint when possible:

GOCACHE=/tmp/scriberr-go-cache go test ./internal/api ./internal/config ./internal/database ./internal/repository ./internal/transcription/... ./cmd/server ./pkg/logger ./pkg/middleware
GOCACHE=/tmp/scriberr-go-cache go vet ./internal/api ./internal/config ./internal/database ./internal/repository ./internal/transcription/... ./cmd/server ./pkg/logger ./pkg/middleware
git diff --check

Real engine validation is opt-in:

SCRIBERR_ENGINE_ITEST=1 SPEECH_ENGINE_AUTO_DOWNLOAD=true GOCACHE=/tmp/scriberr-go-cache go test ./internal/transcription/... -run 'Test.*RealEngine|Test.*JFK'

Performance-oriented manual validation should record:

• audio file used,
• selected provider and resolved provider,
• model download time if any,
• transcription wall time,
• CPU/GPU mode,
• resulting transcript word/segment counts.

EWI-Sprint 0: Integration Inventory and Commit Plan

Goal: lock down the exact files, dependencies, and deletion targets before changing runtime behavior.

Tasks:

• Inventory current transcription API handlers, queue package usage, internal/transcription packages, server startup wiring, config fields, schema fields, docs, and Docker env examples.
• Identify all imports of legacy adapter/registry/pipeline code and decide whether each file is removed, replaced, or kept as a compatibility wrapper.
• Confirm references/engine compiles as a local replacement module and document any platform/runtime prerequisites.
• Write a route/API impact matrix for create/submit/retry/cancel/models/logs/executions/events.
• Create a commit checklist for the remaining sprints.

Acceptance criteria:

• Deletion list for legacy Python adapter stack is explicit.
• No implementation sprint starts with unknown server startup dependencies.
• The intended commit grouping is documented.

Testing focus:

• Compile-only discovery if Go dependencies are available.
• No product behavior tests required.

EWI-Sprint 1: Config and Engine Module Wiring

Goal: add engine/worker configuration and module wiring without starting workers or downloading models.

Tasks:

• Add require scriberr-engine v0.0.0 and replace scriberr-engine => ./references/engine.
• Add EngineConfig and WorkerConfig to internal/config.
• Parse and validate:
  • SPEECH_ENGINE_CACHE_DIR
  • SPEECH_ENGINE_PROVIDER
  • SPEECH_ENGINE_THREADS
  • SPEECH_ENGINE_MAX_LOADED
  • SPEECH_ENGINE_AUTO_DOWNLOAD
  • TRANSCRIPTION_WORKERS
  • TRANSCRIPTION_QUEUE_POLL_INTERVAL
  • TRANSCRIPTION_LEASE_TIMEOUT
• Make invalid numeric, duration, boolean, and provider values fail startup with clear config errors.
• Keep startup free of model downloads.
• Start de-emphasizing WHISPERX_ENV in config without breaking existing callers until legacy startup code is removed.

Acceptance criteria:

• Defaults match the spec exactly.
• auto, cpu, and cuda provider values parse; other values fail.
• Config errors are actionable and do not panic.

Testing focus:

• Defaults.
• Invalid provider.
• Invalid integer/duration/boolean.
• Auto-download default.
• Worker default remains one worker.

Commit guidance:

• Commit config tests first.
• Commit config implementation and module wiring second.

EWI-Sprint 2: Engine Provider Abstraction

Goal: create a provider boundary that hides scriberr-engine from API, repository, and worker callers.

Tasks:

• Add internal/transcription/engineprovider.
• Define provider, registry, capability, request, result, transcript word/segment, and diarization segment types.
• Implement an in-memory registry with default provider lookup.
• Implement a fake provider for tests.
• Implement local provider wrapping scriberr-engine/speech/engine.
• Map Scriberr requests to engine requests and map engine results back to internal provider results.
• Implement provider capabilities and installed state via engine model metadata and IsModelInstalled.
• Sanitize provider errors before they can be returned to API clients.
• Log detailed errors internally without public path leakage.

Acceptance criteria:

• Only engineprovider imports scriberr-engine.
• Local provider ID() is local.
• Defaults are whisper-base and diarization-default.
• Missing words return Words: [], never nil-dependent API behavior.
• Provider registry supports future non-local providers.

Testing focus:

• Request mapping.
• Result mapping with words.
• Empty words.
• Diarization result mapping.
• Capability listing and installed flags.
• Error sanitization.

Commit guidance:

• Commit interface/fake-provider tests first.
• Commit local provider implementation separately.

EWI-Sprint 3: Queue Schema and Repository Methods

Goal: make transcription job state durable enough for workers, leases, progress, and executions.

Tasks:

• Add schema fields to models.TranscriptionJob:
  • queued_at
  • started_at
  • failed_at
  • progress
  • progress_stage
  • claimed_by
  • claim_expires_at
  • engine_id
• Ensure TranscriptionJobExecution stores provider, model name/family, started/completed/failed timestamps, sanitized error, output JSON path, and request/config JSON.
• Add indexes:
  • idx_transcriptions_queue_claim(status, queued_at)
  • idx_transcriptions_claim_expires_at(claim_expires_at)
• Add repository methods for enqueue, claim, renew, progress, complete, fail, cancel, execution listing, and startup recovery.
• Use transactions for claim and terminal-state updates.
• Keep claim policy isolated behind a FIFO scheduler policy.

Acceptance criteria:

• Claim returns the oldest queued job by queued_at, created_at, and id.
• Concurrent claims do not return the same job.
• Lease renewal updates only the owning worker.
• Startup recovery requeues processing rows regardless of stale process-local owner state.
• Terminal updates keep job and latest execution consistent.

Testing focus:

• Migration/schema fields and indexes.
• Enqueue state transition.
• FIFO claim.
• Concurrent claim race.
• Lease renewal owner mismatch.
• Startup recovery.
• Complete/fail/cancel terminal transactions.

Commit guidance:

• Commit schema/repository tests first.
• Commit schema/model updates and repository implementation second.

EWI-Sprint 4: Durable Worker Service

Goal: implement the worker loop, wake signals, cancellation, stats, leases, and shutdown behavior using fake processors.

Tasks:

• Add internal/transcription/worker.
• Define QueueService as specified.
• Implement enqueue as durable DB update plus non-blocking wake signal.
• Implement workers that poll, claim one job, renew lease, process with cancellable context, and write terminal state through repository/orchestrator results.
• Track cancel funcs for currently running process-local jobs.
• Implement cancel behavior for queued, local running, and orphaned processing jobs.
• Implement queue stats by user.
• Implement clean Start and Stop.

Acceptance criteria:

• Enqueue moves jobs to queued and wakes workers.
• Workers process jobs without duplicate claims.
• Running jobs renew leases until terminal state.
• Stop cancels local running jobs and waits within a bounded timeout.
• Cancel returns conflict for completed/failed/canceled jobs.

Testing focus:

• Enqueue/wake hot path.
• Fake processor completes a job.
• Fake processor observes cancellation.
• Cancel queued.
• Cancel running.
• Claim lease renewal.
• Worker shutdown.
• Queue stats.

Commit guidance:

• Commit queue-service tests first.
• Commit worker implementation separately.

EWI-Sprint 5: Orchestrator, Transcript Mapping, and Speaker Merge

Goal: convert claimed jobs into completed canonical transcripts through provider calls.

Tasks:

• Add internal/transcription/orchestrator.
• Implement Processor with job repository, provider registry, event publisher, and job logger dependencies.
• Resolve audio path, provider, transcription model, diarization model, language, task, and diarization options.
• Create execution rows at processing start.
• Publish progress stages:
  • queued,
  • preparing,
  • transcribing,
  • diarizing,
  • merging,
  • saving,
  • completed/failed/canceled.
• Persist canonical transcript JSON in transcriptions.transcript_text.
• Write the same JSON to data/transcripts/{jobID}/transcript.json and store internal output path.
• Generate fallback segments when needed.
• Preserve words: [] when words are absent.
• Merge diarization speakers into words and segments using overlap.
• Sanitize failures and distinguish user cancellation from engine failure.

Acceptance criteria:

• Fake provider can complete a transcription job end to end.
• Canonical transcript JSON matches the spec.
• No diarization leaves speaker fields absent.
• Diarization assigns stable SPEAKER_00 style labels.
• Failures update job and execution consistently.
• Context cancellation marks canceled, not failed.

Testing focus:

• Transcript mapper with words.
• Transcript mapper without words.
• Plain-text legacy fallback.
• Older JSON without words.
• Segment fallback.
• Word and segment speaker overlap assignment.
• Provider failure sanitization.
• Cancellation path.

Commit guidance:

• Commit mapper/merge tests first.
• Commit orchestrator tests and implementation second.

EWI-Sprint 6: API Wiring for Real Queue Execution

Goal: replace transcription placeholders with queue-backed behavior while preserving canonical API contracts.

Tasks:

• Inject queue service, provider registry/model service, execution service, and log reader into API handler construction.
• Update create/submit to create queued rows and call QueueService.Enqueue.
• Update retry to reset eligible terminal jobs and enqueue a new attempt.
• Update cancel to call QueueService.Cancel.
• Add progress fields to transcription get/list responses.
• Implement transcript endpoint through canonical transcript parser.
• Implement executions endpoint with sanitized metadata.
• Implement logs endpoint as authenticated plain text with sanitization.
• Implement models endpoint from provider capabilities.
• Keep SSE payloads path-safe and progress-shaped.

Acceptance criteria:

• Create/submit return 202 queued resources.
• Queue shutdown produces 503 without losing durable job state.
• Fake engine worker can complete a job, and transcript endpoint returns text, segments, and words.
• Executions endpoint returns execution metadata.
• Logs endpoint returns sanitized text.
• Models endpoint returns local capabilities and installed/default flags.
• No API response/event leaks upload path, temp path, model cache path, or raw internal error details.

Testing focus:

• Create enqueues.
• Submit upload creates file, job, and enqueue.
• Retry valid and conflict states.
• Cancel queued/running/conflict states.
• Transcript canonical response.
• Fake worker completion through API-visible state.
• Events progress and completed payloads.
• Executions/logs/models endpoints.
• Path-leak regression tests.

Commit guidance:

• Commit API tests first.
• Commit dependency injection and service wiring separately.
• Commit endpoint behavior updates last.

EWI-Sprint 7: Server Startup, Shutdown, and Legacy Adapter Removal

Goal: make the real engine worker the default runtime path and remove obsolete Python adapter bootstrapping.

Tasks:

• Update cmd/server/main.go startup order to match the spec.
• Initialize local engine provider registry after DB/repositories and before worker service.
• Run DB recovery before starting workers.
• Start workers before HTTP serving.
• On shutdown, stop workers, cancel running jobs, close engine providers, then close DB.
• Remove server startup dependencies on Python, WHISPERX_ENV, and legacy adapter registration.
• Delete or stop compiling:
  • internal/transcription/adapters/**
  • legacy registry/pipeline abstractions that only serve Python adapters
  • obsolete adapter tests
• Keep compatibility wrappers only when needed to compile API or service boundaries.

Acceptance criteria:

• Fresh server startup does not require Python env setup.
• Startup logs include cache dir, requested provider, resolved provider when available, threads, max-loaded, and auto-download.
• Shutdown releases worker and provider resources.
• Legacy Python adapter code no longer participates in server runtime.

Testing focus:

• Server construction with fake provider/worker where practical.
• Startup recovery is invoked before worker start.
• Shutdown order test or focused unit test around lifecycle coordinator.
• Compile regression proving deleted adapter code is no longer referenced.

Commit guidance:

• Commit lifecycle tests first.
• Commit startup wiring.
• Commit legacy deletion as its own reviewable commit.

EWI-Sprint 8: Real Engine Integration Tests and Performance Smoke

Goal: prove the local engine path works with fixture audio without making CI slow or flaky.

Tasks:

• Add opt-in real engine integration tests gated by SCRIBERR_ENGINE_ITEST=1.
• Use test-audio/jfk.wav for fast transcription verification.
• Skip cleanly with clear messages when ffmpeg, engine runtime, model downloads, CUDA runtime, or network access are unavailable.
• Validate that first-run auto-download works when enabled.
• Validate SPEECH_ENGINE_AUTO_DOWNLOAD=false fails jobs cleanly when models are missing.
• Add a small benchmark or timed smoke test that reports wall time without setting brittle pass/fail thresholds.
• Document manual performance commands for jfk.wav, sample.wav, and optional longer fixtures.

Acceptance criteria:

• Default CI remains fake-provider only.
• Opt-in real test can produce a completed transcript for test-audio/jfk.wav.
• Real test asserts non-empty text and path-safe public outputs.
• Auto-download disabled path fails with a sanitized model-unavailable error.

Testing focus:

• Real local provider transcription with jfk.wav.
• Optional diarization only if model/runtime availability makes it practical.
• Auto-download enabled/disabled behavior.
• No path leakage from real failures.

Commit guidance:

• Commit gated integration tests separately from runtime implementation fixes.

EWI-Sprint 9: Hardening, Cleanup

Goal: audit the full implementation for correctness, performance, privacy, and maintainability.

Tasks:

• Run the full backend test/vet baseline.
• Run focused race/concurrency tests for queue claiming if practical.
• Run opt-in jfk.wav real engine smoke.
• Audit public API responses and events for path/token leakage.
• Audit handler packages for business logic that should move behind services.
• Audit repository terminal updates for transaction boundaries.
• Audit worker shutdown and cancellation behavior.
• Remove dead code, obsolete TODOs, and stale docs from earlier sprints.
• Update devnotes/engine-worker-sprint-tracker.md with final verification results.

Acceptance criteria:

• Full fake-provider test suite passes.
• Real jfk.wav smoke passes or has a documented external dependency blocker.
• No known path leaks in API, events, logs endpoint, or tests.
• Queue restart recovery is covered.
• Commit history is organized by sprint and behavior.

Testing focus:

• Full package tests and vet.
• API regression tests.
• Queue concurrency/recovery tests.
• Transcript compatibility tests.
• Real engine smoke.

Commit guidance:

• Commit hardening fixes in narrow patches.
• Final commit should be docs/tracker updates only.

Minimum Test Coverage Set

The target is not 100% coverage. The minimum set must cover the highest-risk paths:

• Config parse defaults and invalid values.
• Provider request/result mapping and sanitized errors.
• Queue enqueue, claim, lease renew, recovery, cancel queued, cancel running, and no duplicate claim.
• Orchestrator success, provider failure, cancellation, canonical JSON, words absent, and diarization merge.
• API create/submit/retry/cancel/transcript/events/executions/logs/models hot paths.
• Security/path-leak regression for API responses, events, logs, and provider errors.
• Gated real engine transcription using test-audio/jfk.wav.

Completion Definition

This sprint run is complete when:

• Fresh install starts without Python environment setup.
• Missing models download automatically on first job when enabled.
• A transcription moves from queued to processing to completed or failed.
• Completed transcripts include text, segments, and word timestamps when available.
• Missing word timestamps are represented as words: [].
• Diarization assigns public-safe speaker labels when requested and available.
• Events report progress and terminal states.
• Executions and logs endpoints are implemented and sanitized.
• Queue state survives restart and recovers orphaned processing jobs.
• Legacy Python adapter bootstrap is gone from server startup.
• Real jfk.wav smoke has been run or blocked by a documented external dependency.