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git.stella-ops.org/docs/features/checked/jobengine/event-fan-out.md

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Event Fan-Out (SSE/Streaming)

Module

Orchestrator

Status

IMPLEMENTED

Description

Job and pack-run streaming coordinators with stream payload models for real-time SSE event delivery.

Implementation Details

  • Modules: src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/, src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.Core/Domain/Events/
  • Key Classes:
    • JobStreamCoordinator (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/JobStreamCoordinator.cs) - coordinates SSE streaming for job lifecycle events to connected clients
    • PackRunStreamCoordinator (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/PackRunStreamCoordinator.cs) - coordinates streaming for pack-run execution events
    • RunStreamCoordinator (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/RunStreamCoordinator.cs) - coordinates streaming for individual run events
    • SseWriter (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/SseWriter.cs) - writes Server-Sent Events to HTTP response streams
    • StreamOptions (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/StreamOptions.cs) - configuration for stream connections (heartbeat interval, buffer size, timeout)
    • StreamPayloads (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Streaming/StreamPayloads.cs) - typed payload models for stream events (job progress, pack-run status, log lines)
    • StreamEndpoints (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.WebService/Endpoints/StreamEndpoints.cs) - REST endpoints for SSE stream subscription
    • EventEnvelope (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.Core/Domain/Events/EventEnvelope.cs) - typed event envelope wrapping domain events for streaming
    • OrchestratorEventPublisher (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.Infrastructure/Events/OrchestratorEventPublisher.cs) - concrete event publisher routing events to stream coordinators
  • Interfaces: IEventPublisher (src/JobEngine/StellaOps.JobEngine/StellaOps.JobEngine.Core/Domain/Events/IEventPublisher.cs)
  • Source: Feature matrix scan

E2E Test Plan

  • Subscribe to the job stream via StreamEndpoints and trigger a job; verify SSE events are received for each state transition
  • Subscribe to the pack-run stream via PackRunStreamCoordinator and execute a pack; verify progress events include step index, status, and log lines
  • Verify heartbeat: subscribe to a stream and wait without events; confirm heartbeat events arrive at the StreamOptions configured interval
  • Subscribe with two clients to the same job stream and verify both receive identical events (fan-out via JobStreamCoordinator)
  • Disconnect a client mid-stream and verify the stream coordinator cleans up the connection without affecting other subscribers
  • Trigger a rapid sequence of events and verify SseWriter delivers them in order without drops
  • Verify stream payloads: each event contains a typed payload matching the StreamPayloads model
  • Test stream timeout: idle for longer than StreamOptions.Timeout and verify the connection closes gracefully