Re-route asyncio plasma code path through raylet instead of direct plasma connection (#7234)

python/ray/experimental/async_api.py

@@ -16,7 +16,7 @@ async def _async_init():
         worker = ray.worker.global_worker
         loop = asyncio.get_event_loop()
         handler = PlasmaEventHandler(loop, worker)
-        worker.core_worker.subscribe_to_plasma(handler)
+        worker.core_worker.set_plasma_added_callback(handler)
         logger.debug("AsyncPlasma Connection Created!")
 
 

python/ray/experimental/async_plasma.py

@@ -71,6 +71,8 @@ class PlasmaEventHandler:
 
         future = PlasmaObjectFuture(loop=self._loop)
         self._waiting_dict[object_id].append(future)
-        self.check_immediately(object_id)
-
+        if not self.check_immediately(object_id) and len(
+                self._waiting_dict[object_id]) == 1:
+            # Only subscribe once
+            self._worker.core_worker.subscribe_to_plasma_object(object_id)
         return future