Added Readiness probe (#22507)

backend/open_webui/main.py

@@ -702,6 +702,9 @@ async def lifespan(app: FastAPI):
         except Exception as e:
             log.warning(f"Failed to initialize tool/terminal servers at startup: {e}")
 
+    # Mark application as ready to accept traffic from a startup perspective.
+    app.state.startup_complete = True
+
     yield
 
     if hasattr(app.state, "redis_task_command_listener"):
@@ -716,6 +719,9 @@ app = FastAPI(
     lifespan=lifespan,
 )
 
+# Used by readiness checks to gate traffic until startup work is done.
+app.state.startup_complete = False
+
 # For Open WebUI OIDC/OAuth2
 oauth_manager = OAuthManager(app)
 app.state.oauth_manager = oauth_manager
@@ -2602,6 +2608,47 @@ async def healthcheck():
     return {"status": True}
 
 
+@app.get("/ready")
+async def readiness_check():
+    """
+    Returns 200 only when the application is ready to accept traffic.
+    """
+
+    # Ensure application startup work has completed
+    if not getattr(app.state, "startup_complete", False):
+        log.info("Readiness check failed: startup not complete")
+        raise HTTPException(
+            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+            detail="Startup not complete",
+        )
+
+    # Check database connectivity
+    try:
+        ScopedSession.execute(text("SELECT 1;")).all()
+    except Exception as e:
+        log.warning(f"Readiness check DB ping failed: {e!r}")
+        raise HTTPException(
+            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+            detail="Database not ready",
+        )
+
+    # Check Redis connectivity if configured
+    redis = app.state.redis
+    if redis is not None:
+        try:
+            pong = await redis.ping()
+            if pong is False:
+                raise Exception("Redis PING returned False")
+        except Exception as e:
+            log.warning(f"Readiness check Redis ping failed: {e!r}")
+            raise HTTPException(
+                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                detail="Redis not ready",
+            )
+
+    return {"status": True}
+
+
 @app.get("/health/db")
 async def healthcheck_with_db():
     ScopedSession.execute(text("SELECT 1;")).all()