Feat/monitor task (#11116)

### What problem does this PR solve?

Show task executor.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/utils/health_utils.py

@@ -13,6 +13,8 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 #
+from datetime import datetime
+import json
 import os
 import requests
 from timeit import default_timer as timer
@@ -148,7 +150,7 @@ def check_ragflow_server_alive():
     try:
         url = f'http://{settings.HOST_IP}:{settings.HOST_PORT}/v1/system/ping'
         if '0.0.0.0' in url:
-            url.replace('0.0.0.0', '127.0.0.1')
+            url = url.replace('0.0.0.0', '127.0.0.1')
         response = requests.get(url)
         if response.status_code == 200:
             return {"status": "alive", "message": f"Confirm elapsed: {(timer() - start_time) * 1000.0:.1f} ms."}
@@ -161,6 +163,26 @@ def check_ragflow_server_alive():
         }
 
 
+def check_task_executor_alive():
+    task_executor_heartbeats = {}
+    try:
+        task_executors = REDIS_CONN.smembers("TASKEXE")
+        now = datetime.now().timestamp()
+        for task_executor_id in task_executors:
+            heartbeats = REDIS_CONN.zrangebyscore(task_executor_id, now - 60 * 30, now)
+            heartbeats = [json.loads(heartbeat) for heartbeat in heartbeats]
+            task_executor_heartbeats[task_executor_id] = heartbeats
+        if task_executor_heartbeats:
+            return {"status": "alive", "message": task_executor_heartbeats}
+        else:
+            return {"status": "timeout", "message": "Not found any task executor."}
+    except Exception as e:
+        return {
+            "status": "timeout",
+            "message": f"error: {str(e)}"
+        }
+
+
 def run_health_checks() -> tuple[dict, bool]:
     result: dict[str, str | dict] = {}