Merge pull request #11745 from AlanCoding/cancel_rework_no_close

Close database connections while processing job output

awx/main/dispatch/control.py

@@ -37,18 +37,24 @@ def status(self, *args, **kwargs):
     def running(self, *args, **kwargs):
         return self.control_with_reply('running', *args, **kwargs)
 
+    def cancel(self, task_ids, *args, **kwargs):
+        return self.control_with_reply('cancel', *args, extra_data={'task_ids': task_ids}, **kwargs)
+
     @classmethod
     def generate_reply_queue_name(cls):
         return f"reply_to_{str(uuid.uuid4()).replace('-','_')}"
 
-    def control_with_reply(self, command, timeout=5):
+    def control_with_reply(self, command, timeout=5, extra_data=None):
         logger.warning('checking {} {} for {}'.format(self.service, command, self.queuename))
         reply_queue = Control.generate_reply_queue_name()
         self.result = None
 
         with pg_bus_conn(new_connection=True) as conn:
             conn.listen(reply_queue)
-            conn.notify(self.queuename, json.dumps({'control': command, 'reply_to': reply_queue}))
+            send_data = {'control': command, 'reply_to': reply_queue}
+            if extra_data:
+                send_data.update(extra_data)
+            conn.notify(self.queuename, json.dumps(send_data))
 
             for reply in conn.events(select_timeout=timeout, yield_timeouts=True):
                 if reply is None:

awx/main/dispatch/worker/base.py

@@ -63,7 +63,7 @@ def listening_on(self):
     def control(self, body):
         logger.warning(f'Received control signal:\n{body}')
         control = body.get('control')
-        if control in ('status', 'running'):
+        if control in ('status', 'running', 'cancel'):
             reply_queue = body['reply_to']
             if control == 'status':
                 msg = '\n'.join([self.listening_on, self.pool.debug()])
@@ -72,6 +72,17 @@ def control(self, body):
                 for worker in self.pool.workers:
                     worker.calculate_managed_tasks()
                     msg.extend(worker.managed_tasks.keys())
+            elif control == 'cancel':
+                msg = []
+                task_ids = set(body['task_ids'])
+                for worker in self.pool.workers:
+                    task = worker.current_task
+                    if task and task['uuid'] in task_ids:
+                        logger.warn(f'Sending SIGTERM to task id={task["uuid"]}, task={task.get("task")}, args={task.get("args")}')
+                        os.kill(worker.pid, signal.SIGTERM)
+                        msg.append(task['uuid'])
+                if task_ids and not msg:
+                    logger.info(f'Could not locate running tasks to cancel with ids={task_ids}')
 
             with pg_bus_conn() as conn:
                 conn.notify(reply_queue, json.dumps(msg))

awx/main/management/commands/run_dispatcher.py

@@ -1,6 +1,7 @@
 # Copyright (c) 2015 Ansible, Inc.
 # All Rights Reserved.
 import logging
+import yaml
 
 from django.conf import settings
 from django.core.cache import cache as django_cache
@@ -30,7 +31,16 @@ def add_arguments(self, parser):
             '--reload',
             dest='reload',
             action='store_true',
-            help=('cause the dispatcher to recycle all of its worker processes;' 'running jobs will run to completion first'),
+            help=('cause the dispatcher to recycle all of its worker processes; running jobs will run to completion first'),
+        )
+        parser.add_argument(
+            '--cancel',
+            dest='cancel',
+            help=(
+                'Cancel a particular task id. Takes either a single id string, or a JSON list of multiple ids. '
+                'Can take in output from the --running argument as input to cancel all tasks. '
+                'Only running tasks can be canceled, queued tasks must be started before they can be canceled.'
+            ),
         )
 
     def handle(self, *arg, **options):
@@ -42,6 +52,16 @@ def handle(self, *arg, **options):
             return
         if options.get('reload'):
             return Control('dispatcher').control({'control': 'reload'})
+        if options.get('cancel'):
+            cancel_str = options.get('cancel')
+            try:
+                cancel_data = yaml.safe_load(cancel_str)
+            except Exception:
+                cancel_data = [cancel_str]
+            if not isinstance(cancel_data, list):
+                cancel_data = [cancel_str]
+            print(Control('dispatcher').cancel(cancel_data))
+            return
 
         # It's important to close these because we're _about_ to fork, and we
         # don't want the forked processes to inherit the open sockets

awx/main/models/mixins.py

@@ -412,6 +412,11 @@ class TaskManagerJobMixin(TaskManagerUnifiedJobMixin):
     class Meta:
         abstract = True
 
+    def get_jobs_fail_chain(self):
+        if self.project_update_id:
+            return [self.project_update]
+        return []
+
 
 class TaskManagerUpdateOnLaunchMixin(TaskManagerUnifiedJobMixin):
     class Meta:

awx/main/models/unified_jobs.py

@@ -1395,23 +1395,6 @@ def signal_start(self, **kwargs):
         # Done!
         return True
 
-    @property
-    def actually_running(self):
-        # returns True if the job is running in the appropriate dispatcher process
-        running = False
-        if all([self.status == 'running', self.celery_task_id, self.execution_node]):
-            # If the job is marked as running, but the dispatcher
-            # doesn't know about it (or the dispatcher doesn't reply),
-            # then cancel the job
-            timeout = 5
-            try:
-                running = self.celery_task_id in ControlDispatcher('dispatcher', self.controller_node or self.execution_node).running(timeout=timeout)
-            except socket.timeout:
-                logger.error('could not reach dispatcher on {} within {}s'.format(self.execution_node, timeout))
-            except Exception:
-                logger.exception("error encountered when checking task status")
-        return running
-
     @property
     def can_cancel(self):
         return bool(self.status in CAN_CANCEL)
@@ -1421,27 +1404,61 @@ def _build_job_explanation(self):
             return 'Previous Task Canceled: {"job_type": "%s", "job_name": "%s", "job_id": "%s"}' % (self.model_to_str(), self.name, self.id)
         return None
 
+    def fallback_cancel(self):
+        if not self.celery_task_id:
+            self.refresh_from_db(fields=['celery_task_id'])
+        self.cancel_dispatcher_process()
+
+    def cancel_dispatcher_process(self):
+        """Returns True if dispatcher running this job acknowledged request and sent SIGTERM"""
+        if not self.celery_task_id:
+            return
+        canceled = []
+        try:
+            # Use control and reply mechanism to cancel and obtain confirmation
+            timeout = 5
+            canceled = ControlDispatcher('dispatcher', self.controller_node).cancel([self.celery_task_id])
+        except socket.timeout:
+            logger.error(f'could not reach dispatcher on {self.controller_node} within {timeout}s')
+        except Exception:
+            logger.exception("error encountered when checking task status")
+        return bool(self.celery_task_id in canceled)  # True or False, whether confirmation was obtained
+
     def cancel(self, job_explanation=None, is_chain=False):
         if self.can_cancel:
             if not is_chain:
                 for x in self.get_jobs_fail_chain():
                     x.cancel(job_explanation=self._build_job_explanation(), is_chain=True)
 
+            cancel_fields = []
             if not self.cancel_flag:
                 self.cancel_flag = True
                 self.start_args = ''  # blank field to remove encrypted passwords
-                cancel_fields = ['cancel_flag', 'start_args']
-                if self.status in ('pending', 'waiting', 'new'):
-                    self.status = 'canceled'
-                    cancel_fields.append('status')
-                if self.status == 'running' and not self.actually_running:
-                    self.status = 'canceled'
-                    cancel_fields.append('status')
+                cancel_fields.extend(['cancel_flag', 'start_args'])
+                connection.on_commit(lambda: self.websocket_emit_status("canceled"))
+
                 if job_explanation is not None:
                     self.job_explanation = job_explanation
                     cancel_fields.append('job_explanation')
-                self.save(update_fields=cancel_fields)
-                self.websocket_emit_status("canceled")
+
+            controller_notified = False
+            if self.celery_task_id:
+                controller_notified = self.cancel_dispatcher_process()
+
+            else:
+                # Avoid race condition where we have stale model from pending state but job has already started,
+                # its checking signal but not cancel_flag, so re-send signal after this database commit
+                connection.on_commit(self.fallback_cancel)
+
+            # If a SIGTERM signal was sent to the control process, and acked by the dispatcher
+            # then we want to let its own cleanup change status, otherwise change status now
+            if not controller_notified:
+                if self.status != 'canceled':
+                    self.status = 'canceled'
+                    cancel_fields.append('status')
+
+            self.save(update_fields=cancel_fields)
+
         return self.cancel_flag
 
     @property

awx/main/models/workflow.py

@@ -723,11 +723,10 @@ def get_notification_friendly_name(self):
     def preferred_instance_groups(self):
         return []
 
-    @property
-    def actually_running(self):
+    def cancel_dispatcher_process(self):
         # WorkflowJobs don't _actually_ run anything in the dispatcher, so
         # there's no point in asking the dispatcher if it knows about this task
-        return self.status == 'running'
+        return True
 
 
 class WorkflowApprovalTemplate(UnifiedJobTemplate, RelatedJobsMixin):

awx/main/tasks/callback.py

@@ -6,17 +6,16 @@
 import stat
 
 # Django
-from django.utils.timezone import now
 from django.conf import settings
 from django_guid import get_guid
 from django.utils.functional import cached_property
+from django.db import connections
 
 # AWX
 from awx.main.redact import UriCleaner
 from awx.main.constants import MINIMAL_EVENTS, ANSIBLE_RUNNER_NEEDS_UPDATE_MESSAGE
 from awx.main.utils.update_model import update_model
 from awx.main.queue import CallbackQueueDispatcher
-from awx.main.tasks.signals import signal_callback
 
 logger = logging.getLogger('awx.main.tasks.callback')
 
@@ -175,28 +174,6 @@ def event_handler(self, event_data):
 
         return False
 
-    def cancel_callback(self):
-        """
-        Ansible runner callback to tell the job when/if it is canceled
-        """
-        unified_job_id = self.instance.pk
-        if signal_callback():
-            return True
-        try:
-            self.instance = self.update_model(unified_job_id)
-        except Exception:
-            logger.exception(f'Encountered error during cancel check for {unified_job_id}, canceling now')
-            return True
-        if not self.instance:
-            logger.error('unified job {} was deleted while running, canceling'.format(unified_job_id))
-            return True
-        if self.instance.cancel_flag or self.instance.status == 'canceled':
-            cancel_wait = (now() - self.instance.modified).seconds if self.instance.modified else 0
-            if cancel_wait > 5:
-                logger.warning('Request to cancel {} took {} seconds to complete.'.format(self.instance.log_format, cancel_wait))
-            return True
-        return False
-
     def finished_callback(self, runner_obj):
         """
         Ansible runner callback triggered on finished run
@@ -227,6 +204,8 @@ def status_handler(self, status_data, runner_config):
 
             with disable_activity_stream():
                 self.instance = self.update_model(self.instance.pk, job_args=json.dumps(runner_config.command), job_cwd=runner_config.cwd, job_env=job_env)
+            # We opened a connection just for that save, close it here now
+            connections.close_all()
         elif status_data['status'] == 'failed':
             # For encrypted ssh_key_data, ansible-runner worker will open and write the
             # ssh_key_data to a named pipe. Then, once the podman container starts, ssh-agent will

awx/main/tasks/jobs.py

@@ -487,6 +487,7 @@ def run(self, pk, **kwargs):
             self.instance.log_lifecycle("preparing_playbook")
             if self.instance.cancel_flag or signal_callback():
                 self.instance = self.update_model(self.instance.pk, status='canceled')
+
             if self.instance.status != 'running':
                 # Stop the task chain and prevent starting the job if it has
                 # already been canceled.
@@ -589,7 +590,7 @@ def run(self, pk, **kwargs):
                     event_handler=self.runner_callback.event_handler,
                     finished_callback=self.runner_callback.finished_callback,
                     status_handler=self.runner_callback.status_handler,
-                    cancel_callback=self.runner_callback.cancel_callback,
+                    cancel_callback=signal_callback,
                     **params,
                 )
             else:
@@ -1626,7 +1627,7 @@ def post_run_hook(self, inventory_update, status):
 
         handler = SpecialInventoryHandler(
             self.runner_callback.event_handler,
-            self.runner_callback.cancel_callback,
+            signal_callback,
             verbosity=inventory_update.verbosity,
             job_timeout=self.get_instance_timeout(self.instance),
             start_time=inventory_update.started,

awx/main/tasks/receptor.py

@@ -12,6 +12,7 @@
 
 # Django
 from django.conf import settings
+from django.db import connections
 
 # Runner
 import ansible_runner
@@ -25,6 +26,7 @@
     cleanup_new_process,
 )
 from awx.main.constants import MAX_ISOLATED_PATH_COLON_DELIMITER
+from awx.main.tasks.signals import signal_state, signal_callback, SignalExit
 
 # Receptorctl
 from receptorctl.socket_interface import ReceptorControl
@@ -335,24 +337,32 @@ def _run_internal(self, receptor_ctl):
             shutil.rmtree(artifact_dir)
 
         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,
-        # we yank the socket out from underneath the processor, which will cause it
-        # to exit. A reference to the processor_future is passed into the cancel_watcher_future,
-        # Which exits if the job has finished normally. The context manager ensures we do not
-        # leave any threads laying around.
-        with concurrent.futures.ThreadPoolExecutor(max_workers=2) as executor:
+
+        connections.close_all()
+
+        # "processor" and the main thread will be separate threads.
+        # If a cancel happens, the main thread will encounter an exception, in which case
+        # we yank the socket out from underneath the processor, which will cause it to exit.
+        # The ThreadPoolExecutor context manager ensures we do not leave any threads laying around.
+        with concurrent.futures.ThreadPoolExecutor(max_workers=1) as executor:
             processor_future = executor.submit(self.processor, resultfile)
-            cancel_watcher_future = executor.submit(self.cancel_watcher, processor_future)
-            futures = [processor_future, cancel_watcher_future]
-            first_future = concurrent.futures.wait(futures, return_when=concurrent.futures.FIRST_COMPLETED)
 
-            res = list(first_future.done)[0].result()
-            if res.status == 'canceled':
+            try:
+                signal_state.raise_exception = True
+                # address race condition where SIGTERM was issued after this dispatcher task started
+                if signal_callback():
+                    raise SignalExit()
+                res = processor_future.result()
+            except SignalExit:
                 receptor_ctl.simple_command(f"work cancel {self.unit_id}")
                 resultsock.shutdown(socket.SHUT_RDWR)
                 resultfile.close()
-            elif res.status == 'error':
+                result = namedtuple('result', ['status', 'rc'])
+                res = result('canceled', 1)
+            finally:
+                signal_state.raise_exception = False
+
+            if res.status == 'error':
                 # 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 'result_traceback' in self.task.runner_callback.extra_update_fields:
@@ -446,18 +456,6 @@ def work_type(self):
             return 'local'
         return 'ansible-runner'
 
-    @cleanup_new_process
-    def cancel_watcher(self, processor_future):
-        while True:
-            if processor_future.done():
-                return processor_future.result()
-
-            if self.task.runner_callback.cancel_callback():
-                result = namedtuple('result', ['status', 'rc'])
-                return result('canceled', 1)
-
-            time.sleep(1)
-
     @property
     def pod_definition(self):
         ee = self.task.instance.execution_environment