M22: implement operational observability

backend/app/main.py

@@ -1,3 +1,4 @@
+import logging
 import uuid
 from contextlib import asynccontextmanager
 
@@ -19,6 +20,7 @@ from app.api.routers import (
     integrations,
     knowledge,
     mcp_integrations,
+    observability,
     search,
     users,
     vehicles,
@@ -28,9 +30,19 @@ from app.api.routers.auth import bootstrap_initial_admin
 from app.core.config import PRODUCT_NAME, get_settings
 from app.core.db import SessionLocal
 from app.core.errors import AppError, error_body
+from app.core.observability import (
+    DATABASE_READY,
+    configure_logging,
+    correlation_id_context,
+    correlation_id_for,
+    request_finished,
+    request_started,
+)
 from app.services.dispatcher import start_background_dispatcher, stop_background_dispatcher
 
 settings = get_settings()
+configure_logging(settings.log_level)
+request_logger = logging.getLogger("mobilityops.request")
 
 
 @asynccontextmanager
@@ -53,6 +65,34 @@ app.add_middleware(
     https_only=settings.session_cookie_secure,
 )
 
+
+@app.middleware("http")
+async def request_observability(request: Request, call_next):
+    correlation_id = correlation_id_for(request)
+    request.state.correlation_id = correlation_id
+    token = correlation_id_context.set(correlation_id)
+    started_at = request_started()
+    status_code = 500
+    try:
+        response = await call_next(request)
+        status_code = response.status_code
+        response.headers["X-Correlation-Id"] = correlation_id
+        return response
+    finally:
+        duration = request_finished(request, status_code, started_at)
+        request_logger.info(
+            "request_completed",
+            extra={
+                "method": request.method,
+                "path": request.url.path,
+                "status_code": status_code,
+                "duration_ms": round(duration * 1000, 2),
+                "client_ip": request.client.host if request.client else None,
+            },
+        )
+        correlation_id_context.reset(token)
+
+
 app.add_middleware(
     CORSMiddleware,
     allow_origins=[o.strip() for o in settings.cors_allow_origins.split(",")],
@@ -63,21 +103,26 @@ app.add_middleware(
 
 
 @app.exception_handler(AppError)
-def handle_app_error(_request: Request, exc: AppError) -> JSONResponse:
+def handle_app_error(request: Request, exc: AppError) -> JSONResponse:
     return JSONResponse(
         status_code=exc.status_code,
-        content=error_body(exc.code, exc.message, exc.correlation_id, exc.details),
+        content=error_body(
+            exc.code,
+            exc.message,
+            request.state.correlation_id,
+            exc.details,
+        ),
     )
 
 
 @app.exception_handler(HTTPException)
-def handle_http_exception(_request: Request, exc: HTTPException) -> JSONResponse:
+def handle_http_exception(request: Request, exc: HTTPException) -> JSONResponse:
     return JSONResponse(
         status_code=exc.status_code,
         content=error_body(
             code=str(exc.status_code),
             message=str(exc.detail),
-            correlation_id=str(uuid.uuid4()),
+            correlation_id=getattr(request.state, "correlation_id", str(uuid.uuid4())),
             details={},
         ),
     )
@@ -101,10 +146,12 @@ def readiness() -> JSONResponse:
         with SessionLocal() as db:
             db.execute(text("SELECT 1"))
     except Exception:  # noqa: BLE001 -- readiness must convert infrastructure errors to 503
-        return JSONResponse(
-            status_code=503,
-            content={"status": "not_ready", "service": "mobilityops-api", "database": "down"},
-        )
+        DATABASE_READY.set(0)
+    DATABASE_READY.set(1)
+    return JSONResponse(
+        status_code=503,
+        content={"status": "not_ready", "service": "mobilityops-api", "database": "down"},
+    )
     return JSONResponse(content={"status": "ready", "service": "mobilityops-api", "database": "up"})
 
 
@@ -135,3 +182,4 @@ app.include_router(mcp_integrations.router)
 app.include_router(search.router)
 app.include_router(integration_status.router)
 app.include_router(users.router)
+app.include_router(observability.router)