Merge pull request #10212 from sarabrajsingh/bugfix/create-seperator-worker-thread-for-transmit-jobs-9952

created a TransmitterThread class to start transmit jobs within. Surr…

SUMMARY

Surfaced this bug while fixing issue #9952.
Receptor-ctl would hang trying to read from a socket pair that is never closed, when the transmit job was executed yet threw an exception. This anomaly occurred when using a k8s cluster (Openshift in our case) as the execution environment.
FYI - for now, this only applies to container groups.
We moved the transmit function to execute in its own thread, and rejoin the calling function (_run_internal) when it finishes transmitting, and bubbling up exceptions if any occurred in the thread.

ISSUE TYPE


Bugfix Pull Request

COMPONENT NAME


API

AWX VERSION

awx: 19.1.0

ADDITIONAL INFORMATION

Steps to reproduce bug:

Create an ansible project with some files (or roles) and commit to a git repository
Purposely commit a broken symlink on any file in the project files to git
Create a credential set that authenticates to your k8s cluster in AWX
Create a container instance group that leverages the credentials from Step 3 in AWX
Create a project in AWX that leverages the ansible project/git repo from Step 1
Create a job template that leverages the AWX project from Step 4 and set your EE to the container instance group from Step 3
Execute the job from Step 5

Reviewed-by: Shane McDonald <me@shanemcd.com>

awx/main/tasks.py

@@ -28,6 +28,7 @@ import threading
 import concurrent.futures
 from base64 import b64encode
 import subprocess
+import sys
 
 # Django
 from django.conf import settings
@@ -2893,6 +2894,16 @@ def deep_copy_model_obj(model_module, model_name, obj_pk, new_obj_pk, user_pk, u
         update_inventory_computed_fields.delay(new_obj.id)
 
 
+class TransmitterThread(threading.Thread):
+    def run(self):
+        self.exc = None
+
+        try:
+            super().run()
+        except Exception:
+            self.exc = sys.exc_info()
+
+
 class AWXReceptorJob:
     def __init__(self, task=None, runner_params=None):
         self.task = task
@@ -2920,7 +2931,8 @@ class AWXReceptorJob:
         # reading.
         sockin, sockout = socket.socketpair()
 
-        threading.Thread(target=self.transmit, args=[sockin]).start()
+        transmitter_thread = TransmitterThread(target=self.transmit, args=[sockin])
+        transmitter_thread.start()
 
         # submit our work, passing
         # in the right side of our socketpair for reading.
@@ -2930,6 +2942,11 @@ class AWXReceptorJob:
         sockin.close()
         sockout.close()
 
+        if transmitter_thread.exc:
+            raise transmitter_thread.exc[1].with_traceback(transmitter_thread.exc[2])
+
+        transmitter_thread.join()
+
         resultsock, resultfile = receptor_ctl.get_work_results(self.unit_id, return_socket=True, return_sockfile=True)
         # Both "processor" and "cancel_watcher" are spawned in separate threads.
         # We wait for the first one to return. If cancel_watcher returns first,
@@ -2960,7 +2977,6 @@ class AWXReceptorJob:
                     logger.warn(f"Could not launch pod for {log_name}. Exceeded quota.")
                     self.task.update_model(self.task.instance.pk, status='pending')
                     return
-
                 # If ansible-runner ran, but an error occured at runtime, the traceback information
                 # is saved via the status_handler passed in to the processor.
                 if state_name == 'Succeeded':
@@ -2976,10 +2992,11 @@ class AWXReceptorJob:
         if not settings.IS_K8S and self.work_type == 'local':
             self.runner_params['only_transmit_kwargs'] = True
 
-        ansible_runner.interface.run(streamer='transmit', _output=_socket.makefile('wb'), **self.runner_params)
-
-        # Socket must be shutdown here, or the reader will hang forever.
-        _socket.shutdown(socket.SHUT_WR)
+        try:
+            ansible_runner.interface.run(streamer='transmit', _output=_socket.makefile('wb'), **self.runner_params)
+        finally:
+            # Socket must be shutdown here, or the reader will hang forever.
+            _socket.shutdown(socket.SHUT_WR)
 
     def processor(self, resultfile):
         return ansible_runner.interface.run(