remote/coordinator: handle polling tasks separately

Reacquiring orphaned resources can take some time, but we don't want to
block saving or scheduling in the meantime, so split them into separate
asyncio tasks.

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>

Author: jluebbe

labgrid/remote/coordinator.py

@@ -211,7 +211,7 @@ class Coordinator(labgrid_coordinator_pb2_grpc.CoordinatorServicer):
     def __init__(self) -> None:
         self.places: dict[str, Place] = {}
         self.reservations = {}
-        self.poll_task = None
+        self.poll_tasks = []
         self.save_scheduled = False
 
         self.lock = asyncio.Lock()
@@ -220,35 +220,33 @@ def __init__(self) -> None:
         self.load()
 
         self.loop = asyncio.get_running_loop()
-        self.poll_task = self.loop.create_task(self.poll(), name="coordinator-poll")
+        for name in ["save", "reacquire", "schedule"]:
+            step_func = getattr(self, f"_poll_step_{name}")
+            task = self.loop.create_task(self.poll(step_func), name=f"coordinator-poll-{name}")
+            self.poll_tasks.append(task)
 
-    async def _poll_step(self):
+    async def _poll_step_save(self):
         # save changes
-        try:
-            if self.save_scheduled:
-                with warn_if_slow("save changes"):
-                    await self.save()
-        except Exception:  # pylint: disable=broad-except
-            traceback.print_exc()
+        if self.save_scheduled:
+            with warn_if_slow("save changes"):
+                await self.save()
+
+    async def _poll_step_reacquire(self):
         # try to re-acquire orphaned resources
-        try:
-            async with self.lock:
-                with warn_if_slow("reacquire orphaned resources"):
-                    await self._reacquire_orphaned_resources()
-        except Exception:  # pylint: disable=broad-except
-            traceback.print_exc()
+        async with self.lock:
+            with warn_if_slow("reacquire orphaned resources"):
+                await self._reacquire_orphaned_resources()
+
+    async def _poll_step_schedule(self):
         # update reservations
-        try:
-            with warn_if_slow("schedule reservations"):
-                self.schedule_reservations()
-        except Exception:  # pylint: disable=broad-except
-            traceback.print_exc()
+        with warn_if_slow("schedule reservations"):
+            self.schedule_reservations()
 
-    async def poll(self):
+    async def poll(self, step_func):
         while not self.loop.is_closed():
             try:
                 await asyncio.sleep(15.0)
-                await self._poll_step()
+                await step_func()
             except asyncio.CancelledError:
                 break
             except Exception:  # pylint: disable=broad-except