Make actor runtime cancellation immediate

tractor/_actor.py

@@ -503,8 +503,8 @@ class Actor:
             log.runtime(f"Peers is {self._peers}")
 
             if not self._peers:  # no more channels connected
-                self._no_more_peers.set()
                 log.runtime("Signalling no more peer channels")
+                self._no_more_peers.set()
 
             # # XXX: is this necessary (GC should do it?)
             if chan.connected():
@@ -671,7 +671,28 @@ class Actor:
                         f"{ns}.{funcname}({kwargs})")
                     if ns == 'self':
                         func = getattr(self, funcname)
-                        if funcname == '_cancel_task':
+                        if funcname == 'cancel':
+
+                            # don't start entire actor runtime cancellation if this
+                            # actor is in debug mode
+                            pdb_complete = _debug._local_pdb_complete
+                            if pdb_complete:
+                                await pdb_complete.wait()
+
+                            # we immediately start the runtime machinery shutdown
+                            await _invoke(self, cid, chan, func, kwargs)
+
+                            # self.cancel() was called so kill this msg loop
+                            # and break out into ``_async_main()``
+                            log.cancel(
+                                f"Actor {self.uid} was remotely cancelled; "
+                                "waiting on cancellation completion..")
+                            await self._cancel_complete.wait()
+                            loop_cs.cancel()
+                            break
+
+                        elif funcname == '_cancel_task':
+
                             # XXX: a special case is made here for
                             # remote calls since we don't want the
                             # remote actor have to know which channel
@@ -681,6 +702,7 @@ class Actor:
                             #    Portal.run('self', '_cancel_task, cid=did)
                             # without passing the `chan` arg.
                             kwargs['chan'] = chan
+
                     else:
                         # complain to client about restricted modules
                         try:
@@ -706,7 +728,7 @@ class Actor:
 
                     # never allow cancelling cancel requests (results in
                     # deadlock and other weird behaviour)
-                    if func != self.cancel:
+                    # if func != self.cancel:
                     if isinstance(cs, Exception):
                         log.warning(
                             f"Task for RPC func {func} failed with"
@@ -719,20 +741,11 @@ class Actor:
                         # cancelled gracefully if requested
                         self._rpc_tasks[(chan, cid)] = (
                             cs, func, trio.Event())
-                    else:
-                        # self.cancel() was called so kill this msg loop
-                        # and break out into ``_async_main()``
-                        log.warning(
-                            f"Actor {self.uid} was remotely cancelled; "
-                            "waiting on cancellation completion..")
-                        await self._cancel_complete.wait()
-                        loop_cs.cancel()
-                        break
 
                     log.runtime(
                         f"Waiting on next msg for {chan} from {chan.uid}")
-                else:
+
-                    # channel disconnect
+                # end of async for, channel disconnect vis ``trio.EndOfChannel``
                 log.runtime(
                     f"{chan} for {chan.uid} disconnected, cancelling tasks"
                 )
@@ -947,6 +960,9 @@ class Actor:
             # Blocks here as expected until the root nursery is
             # killed (i.e. this actor is cancelled or signalled by the parent)
         except Exception as err:
+            log.info("Closing all actor lifetime contexts")
+            _lifetime_stack.close()
+
             if not registered_with_arbiter:
                 # TODO: I guess we could try to connect back
                 # to the parent through a channel and engage a debugger
@@ -976,11 +992,21 @@ class Actor:
             raise
 
         finally:
-            log.runtime("Root nursery complete")
+            log.info("Root nursery complete")
 
             # tear down all lifetime contexts if not in guest mode
             # XXX: should this just be in the entrypoint?
-            log.cancel("Closing all actor lifetime contexts")
+            log.info("Closing all actor lifetime contexts")
+
+            # TODO: we can't actually do this bc the debugger
+            # uses the _service_n to spawn the lock task, BUT,
+            # in theory if we had the root nursery surround this finally
+            # block it might be actually possible to debug THIS
+            # machinery in the same way as user task code?
+            # if self.name == 'brokerd.ib':
+            #     with trio.CancelScope(shield=True):
+            #         await _debug.breakpoint()
+
             _lifetime_stack.close()
 
             # Unregister actor from the arbiter
@@ -1099,7 +1125,7 @@ class Actor:
             if self._service_n:
                 self._service_n.cancel_scope.cancel()
 
-        log.cancel(f"{self.uid} was sucessfullly cancelled")
+        log.cancel(f"{self.uid} called `Actor.cancel()`")
         self._cancel_complete.set()
         return True