fix(backend/executor): Make executor continuously running and retrying message consumption (#9999)

The executor can sometimes become dangling due to the executor stopping
executing messages but the process is not fully killed. This PR avoids
such a scenario by simply keeping retrying it.

### Changes 🏗️

Introduced continuous_retry decorator and use it to executor message
consumption/

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  <!-- Put your test plan here: -->
  - [x] Run executor service and execute some agents.

autogpt_platform/backend/backend/executor/manager.py

@@ -67,7 +67,7 @@ from backend.util.decorator import error_logged, time_measured
 from backend.util.file import clean_exec_files
 from backend.util.logging import TruncatedLogger, configure_logging
 from backend.util.process import AppProcess, set_service_name
-from backend.util.retry import func_retry
+from backend.util.retry import continuous_retry, func_retry
 from backend.util.service import get_service_client
 from backend.util.settings import Settings
 
@@ -938,8 +938,6 @@ class ExecutionManager(AppProcess):
         self.pool_size = settings.config.num_graph_workers
         self.running = True
         self.active_graph_runs: dict[str, tuple[Future, threading.Event]] = {}
-        signal.signal(signal.SIGTERM, lambda sig, frame: self._on_sigterm())
-        signal.signal(signal.SIGINT, lambda sig, frame: self._on_sigterm())
 
     def run(self):
         pool_size_gauge.set(self.pool_size)
@@ -965,22 +963,29 @@ class ExecutionManager(AppProcess):
         logger.info(f"[{self.service_name}] ⏳ Connecting to Redis...")
         redis.connect()
 
+        threading.Thread(
+            target=lambda: self._consume_execution_cancel(),
+            daemon=True,
+        ).start()
+
+        self._consume_execution_run()
+
+    @continuous_retry()
+    def _consume_execution_cancel(self):
         cancel_client = SyncRabbitMQ(create_execution_queue_config())
         cancel_client.connect()
         cancel_channel = cancel_client.get_channel()
         logger.info(f"[{self.service_name}] ⏳ Starting cancel message consumer...")
-        threading.Thread(
-            target=lambda: (
-                cancel_channel.basic_consume(
-                    queue=GRAPH_EXECUTION_CANCEL_QUEUE_NAME,
-                    on_message_callback=self._handle_cancel_message,
-                    auto_ack=True,
-                ),
-                cancel_channel.start_consuming(),
-            ),
-            daemon=True,
-        ).start()
+        cancel_channel.basic_consume(
+            queue=GRAPH_EXECUTION_CANCEL_QUEUE_NAME,
+            on_message_callback=self._handle_cancel_message,
+            auto_ack=True,
+        )
+        cancel_channel.start_consuming()
+        raise RuntimeError(f"❌ cancel message consumer is stopped: {cancel_channel}")
 
+    @continuous_retry()
+    def _consume_execution_run(self):
         run_client = SyncRabbitMQ(create_execution_queue_config())
         run_client.connect()
         run_channel = run_client.get_channel()
@@ -992,6 +997,7 @@ class ExecutionManager(AppProcess):
         )
         logger.info(f"[{self.service_name}] ⏳ Starting to consume run messages...")
         run_channel.start_consuming()
+        raise RuntimeError(f"❌ run message consumer is stopped: {run_channel}")
 
     def _handle_cancel_message(
         self,
@@ -1090,10 +1096,6 @@ class ExecutionManager(AppProcess):
         super().cleanup()
         self._on_cleanup()
 
-    def _on_sigterm(self):
-        llprint(f"[{self.service_name}] ⚠️ GraphExec SIGTERM received")
-        self._on_cleanup(log=llprint)
-
     def _on_cleanup(self, log=logger.info):
         prefix = f"[{self.service_name}][on_graph_executor_stop {os.getpid()}]"
         log(f"{prefix} ⏳ Shutting down service loop...")
@@ -1110,7 +1112,7 @@ class ExecutionManager(AppProcess):
         redis.disconnect()
 
         log(f"{prefix} ✅ Finished GraphExec cleanup")
-        exit(0)
+        sys.exit(0)
 
 
 # ------- UTILITIES ------- #

autogpt_platform/backend/backend/util/retry.py

@@ -2,6 +2,7 @@ import asyncio
 import logging
 import os
 import threading
+import time
 from functools import wraps
 from uuid import uuid4
 
@@ -80,3 +81,24 @@ func_retry = retry(
     stop=stop_after_attempt(5),
     wait=wait_exponential(multiplier=1, min=1, max=30),
 )
+
+
+def continuous_retry(*, retry_delay: float = 1.0):
+    def decorator(func):
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            while True:
+                try:
+                    return func(*args, **kwargs)
+                except Exception as exc:
+                    logger.exception(
+                        "%s failed with %s — retrying in %.2f s",
+                        func.__name__,
+                        exc,
+                        retry_delay,
+                    )
+                    time.sleep(retry_delay)
+
+        return wrapper
+
+    return decorator