Stream Execution

Stream execution updates using Server-Sent Events (SSE). This endpoint provides real-time execution updates by combining: 1. Historical messages from database (last 200 messages) 2. Live events from Redis (sub-second latency) 3. Workflow state from Temporal (200ms polling) The endpoint supports: - Progressive history loading (no blocking on full history) - Last-Event-ID resumption for reconnection - Gap detection and notification - Graceful degradation when services unavailable - Backward compatible with existing clients Architecture: This endpoint uses the ExecutionStreamer class which orchestrates all phases of streaming: 1. Immediate connection (<50ms) 2. History loading (progressive, one message at a time) 3. History completion notification 4. Live event streaming (until workflow completes or timeout) Gap Recovery: - Supports Last-Event-ID pattern for reconnection - Client sends last_event_id query param or Last-Event-ID header - Server resumes from that point or detects gaps - Buffered events replayed if available - Client notified if gap unrecoverable SSE Event Types: - connected: Initial connection acknowledgment - message: Chat message (history or live) - message_chunk: Streaming message chunk - member_message_chunk: Team member message chunk - history_complete: All historical messages sent - status: Execution status update - tool_started: Tool execution started - tool_completed: Tool execution completed - degraded: Service degradation notification - recovered: Service recovery notification - gap_detected: Gap in event stream detected - error: Error occurred - keepalive: Connection keepalive (comment) SSE Format: - id: {execution_id}_{counter}_{timestamp_micros} - event: {event_type} - data: {json object} Args: execution_id: Execution ID to stream request: FastAPI request object (for headers) last_event_id: Last event ID received by client (for resumption) organization: Authenticated organization (injected by auth middleware) db: Database session (injected by dependency) Returns: StreamingResponse with text/event-stream content Raises: HTTPException 404: Execution not found or not authorized HTTPException 500: Critical initialization error