New alert service

services/alert_processor/app/api/sse.py

@@ -0,0 +1,70 @@
+"""
+Server-Sent Events (SSE) API endpoint.
+"""
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import StreamingResponse
+from uuid import UUID
+from redis.asyncio import Redis
+import structlog
+
+from shared.redis_utils import get_redis_client
+from app.services.sse_service import SSEService
+
+logger = structlog.get_logger()
+
+router = APIRouter()
+
+
+@router.get("/sse/alerts/{tenant_id}")
+async def stream_alerts(tenant_id: UUID):
+    """
+    Stream real-time alerts via Server-Sent Events (SSE).
+
+    Usage (frontend):
+    ```javascript
+    const eventSource = new EventSource('/api/v1/sse/alerts/{tenant_id}');
+    eventSource.onmessage = (event) => {
+        const alert = JSON.parse(event.data);
+        console.log('New alert:', alert);
+    };
+    ```
+
+    Response format:
+    ```
+    data: {"id": "...", "event_type": "...", ...}
+
+    data: {"id": "...", "event_type": "...", ...}
+
+    ```
+    """
+    # Get Redis client from shared utilities
+    redis = await get_redis_client()
+    try:
+        sse_service = SSEService(redis)
+
+        async def event_generator():
+            """Generator for SSE stream"""
+            try:
+                async for message in sse_service.subscribe_to_tenant(str(tenant_id)):
+                    # Format as SSE message
+                    yield f"data: {message}\n\n"
+
+            except Exception as e:
+                logger.error("sse_stream_error", error=str(e), tenant_id=str(tenant_id))
+                # Send error message and close
+                yield f"event: error\ndata: {str(e)}\n\n"
+
+        return StreamingResponse(
+            event_generator(),
+            media_type="text/event-stream",
+            headers={
+                "Cache-Control": "no-cache",
+                "Connection": "keep-alive",
+                "X-Accel-Buffering": "no"  # Disable nginx buffering
+            }
+        )
+
+    except Exception as e:
+        logger.error("sse_setup_failed", error=str(e), tenant_id=str(tenant_id))
+        raise HTTPException(status_code=500, detail="Failed to setup SSE stream")