Fix: Watching for updates could be started multiple times

This would have been the source of many duplicate asyncio tasks.

vm_supervisor/models.py

@@ -55,6 +55,7 @@ class VmExecution:
  concurrent_runs: int
  runs_done_event: asyncio.Event
  expire_task: Optional[asyncio.Task] = None
+ update_task: Optional[asyncio.Task] = None
 
  @property
  def is_running(self):
@@ -147,6 +148,13 @@ def cancel_expiration(self) -> bool:
  else:
  return False
 
+ def cancel_update(self) -> bool:
+ if self.update_task:
+ self.update_task.cancel()
+ return True
+ else:
+ return False
+
  async def stop(self):
  if self.times.stopped_at is not None:
  logger.debug(f"VM={self.vm.vm_id} already stopped")
@@ -157,10 +165,12 @@ async def stop(self):
  await self.vm.teardown()
  self.times.stopped_at = datetime.now()
  self.cancel_expiration()
+ self.cancel_update()
 
  def start_watching_for_updates(self, pubsub: PubSub):
- pool = asyncio.get_running_loop()
- pool.create_task(self.watch_for_updates(pubsub=pubsub))
+ if not self.update_task:
+ loop = asyncio.get_running_loop()
+ self.update_task = loop.create_task(self.watch_for_updates(pubsub=pubsub))
 
  async def watch_for_updates(self, pubsub: PubSub):
  await pubsub.msubscribe(