Build Process Saga

Convert build process to use saga framework, implementing streaming I/O pattern for tar data recovery.

Scope

StreamRegistry Infrastructure:

• StreamRegistry (application-level, not framework)
• Maps stream IDs to active readers and staged filesystem paths
• Enables recovery when original stream is gone
• Cleanup hooks for saga completion

Extract Build Actions:

• ReceiveTarAction - stage tar stream to filesystem, handle recovery gracefully
• LoadConfigAction - load app.toml
• DetectStackAction - detect/validate build stack
• ResolveClusterIPAction - resolve cluster.local
• LaunchBuildkitAction - launch buildkit sandbox
• GetNextVersionAction - generate version/artifact IDs
• BuildImageAction - execute buildkit build (long-running)
• ParseServicesAction - parse Procfile and app config services
• CreateVersionAction - create app version entity
• SetActiveVersionAction - set active version on app
• StopOldSandboxesAction - stop sandboxes running old version

Action Factories:

• Create factories with Builder dependencies injected
• Register in SagaRegistry

Definition Registration:

• Register "build-from-tar" definition
• Define action dependencies (DAG structure)

Entry Point:

• Update BuildFromTar() to register tar stream and launch saga
• Pass app name and stream ID via InitialInputs
• Wire up progress callbacks for build status updates
• Cleanup StreamRegistry after saga completes

Testing:

• Success path with real tar data
• Failure injection at each build step
• Recovery scenarios (crash during tar receive, during build, etc.)
• Stream recovery (original stream gone, fallback to staged path)
• Multiple concurrent builds
• Performance benchmarking (saga overhead acceptable)

Performance Tuning:

• Measure saga logging overhead
• Optimize entity writes if needed
• Ensure build times don't regress

Why One Issue

The streaming pattern is unique to builds and requires all pieces working together. Splitting would create incomplete, non-testable code.

Dependencies

Requires: MIR-439 (Saga Framework Foundation)

Reference

RFD 0035: Saga Pattern for Distributed Operations "Example: Build Process Saga with Streaming" section Phase 3 from Migration Strategy