# Passing ActorPool to another ActorPool/Workflow **URL:** \ **Category:** Ray Core\ **Created:** [February 3, 2023, 9:54am UTC](https://discuss.ray.io/t/passing-actorpool-to-another-actorpool-workflow/9225 "2023-02-03T09:54:21Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![joso](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/joso/32/3745_2.png) [@joso](https://discuss.ray.io/u/joso)\ **Post date:** [February 3, 2023, 9:54am UTC](https://discuss.ray.io/t/passing-actorpool-to-another-actorpool-workflow/9225/1 "2023-02-03T09:54:21Z")
Hello everyone, I am trying to pass an ActorPool as a reference to another ActorPool (or Workflow) to use Actors from that passed pool as a resource. Problem Iā€™m facing is that passed ActorPool is pickled and sent to run in a remote python process. This means that effectively copies of ActorPools are created and it results in only one Actor from the pool being used. When I submit to each copy of ActorPool I am mutating the state of each copy, for example to keep track of which actors are in use and which are free. But since I have separate copies they cannot see these mutations. Here is a simple example of my use-case, all unnecessary logic has been removed and blocking operation of DB read/write has been replaced by sleep. This example is using two ActorPools but same behavior applies when I replace one `simple_actor_pool` with Ray Workflow. ```auto import ray import time ray.shutdown() ray.init() @ray.remote class SimpleActor(): def __init__ (self, mark): self.mark = mark def work(self, connector_actor_pool): print ("Start work: ", self.mark) connector_actor_pool.submit(lambda a, v: a.connect.remote(v), {"mark":self.mark}) connector_actor_pool.get_next() print ("Stop work: ", self.mark) @ray.remote class ConnectorActor(): def __init__ (self, con_id): self.con_id = con_id def connect(self, mark): print (f"Connected ConnectorActor: {self.con_id} for SimpleActor {mark}") time.sleep (10) print (f"Disconnected ConnectorActor: {self.con_id} for SimpleActor {mark}") return 1 connector_actor_pool = ray.util.ActorPool( [ ConnectorActor.options(num_cpus=1).remote(con_id=_) for _ in range(2) ] ) simple_actor_pool = ray.util.ActorPool( [ SimpleActor.options(num_cpus=1).remote(mark=_) for _ in range(4) ] ) for i in range (4): simple_actor_pool.submit(lambda a, v: a.work.remote(v), connector_actor_pool) ``` In the code snippet I am instantiating two ActorPools where one `ActorPool` (`connector_actor_pool` , 2 Actors) is being passed as a parameter to Actors from another pool (`simple_actor_pool` , 4 actors). `simple_actor_pool` is behaving as expected, immediately all 4 Actors from that pool are scheduled with tasks. I would like `connector_actor_pool` to be scheduling tasks for both Actors from but it seems that only one Actor from `connector_actor_pool` is being used while other Actor from that pool is never scheduled with any task. As I understand this is due to pickling of `connector_actor_pool` while it is being passed as an argument to `simple_actor_pool`. Here are the logs from previous run: ```auto (SimpleActor pid=26779) Start work: 3 (ConnectorActor pid=26773) Connected ConnectorActor: 1 for SimpleActor {'mark': 3} (SimpleActor pid=26775) Start work: 1 (SimpleActor pid=26777) Start work: 2 (SimpleActor pid=26774) Start work: 0 (SimpleActor pid=26779) Stop work: 3 (ConnectorActor pid=26773) Disconnected ConnectorActor: 1 for SimpleActor {'mark': 3} (ConnectorActor pid=26773) Connected ConnectorActor: 1 for SimpleActor {'mark': 1} (ConnectorActor pid=26773) Disconnected ConnectorActor: 1 for SimpleActor {'mark': 1} (ConnectorActor pid=26773) Connected ConnectorActor: 1 for SimpleActor {'mark': 0} (SimpleActor pid=26775) Stop work: 1 (ConnectorActor pid=26773) Disconnected ConnectorActor: 1 for SimpleActor {'mark': 0} (ConnectorActor pid=26773) Connected ConnectorActor: 1 for SimpleActor {'mark': 2} (SimpleActor pid=26774) Stop work: 0 (ConnectorActor pid=26773) Disconnected ConnectorActor: 1 for SimpleActor {'mark': 2} (SimpleActor pid=26777) Stop work: 2 ``` Only ConnectorActor 1 is running while pool holds 2 ConnectorActors which I would like both to be available for use by `simple_actor_pool` Actors. Finally my question: is there a way to pass ActorPool to another ActorPool or Workflow so that all Actors can use the same other ActorPool instead of getting copies of that pool and effectively only using first Actor from passed pool? ---
**Author:** ![jjyao](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/jjyao/32/1799_2.png) [@jjyao](https://discuss.ray.io/u/jjyao)\ **Post date:** [March 3, 2023, 5:36pm UTC](https://discuss.ray.io/t/passing-actorpool-to-another-actorpool-workflow/9225/2 "2023-03-03T17:36:34Z")
I think you can solve the problem by creating another Actor to wrap/manage ConnectorActorPool: ```auto @ray.remote class ConnectorActorPoolManager: def __init__ (): self.connector_actor_pool = ray.util.ActorPool(...) def submit(work): self.connector_actor_pool.submit(work) @ray.remote class SimpleActor: def work(self, connector_actor_pool_manager): connector_actor_pool_manager.submit(xxxx) ``` Passing actor handle is well supported by Ray. In this case, every SimpleActor has access to the same ConectorActorPool ---
**Author:** ![joso](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/joso/32/3745_2.png) [@joso](https://discuss.ray.io/u/joso)\ **Post date:** [March 7, 2023, 4:17pm UTC](https://discuss.ray.io/t/passing-actorpool-to-another-actorpool-workflow/9225/3 "2023-03-07T16:17:21Z")
Thank you for your answer. Wrapped ActorPool in Actor works perfectly, I just had to wrap submit and get\_next methods to get full functionality of ActorPool. Now I can pass ActorPool references to other Actors in pools or Ray Workflow tasks šŸ™‚