Agentlace

A simple framework for distributed machine learning applications for agent (policy). In many instances we would like to run the agent in a distributed manner (e.g. async, different process, thread, env, or machine). Agentlace faccilites the distributed data stream of nodes, making this connection seamless. Built on a client-server architecture, Agentlace efficiently manages the transport layer for multiple clients and a central server.

SERL (A Software Suite for Sample-Efficient Robotic Reinforcement Learning) provides working examples on how to use agentlace for distributed reinforcement learning via learner and actor.

Manipulator Gym provides a working example on how to use agentlace of separating the environment and policy in a distributed manner.

Installation

cd agentlace
pip install -e .

Quick Start

1. Video streamer example

This showcases how we can use agentlace to stream a video footage of an agent server to a client. The client can also send custom action to the agent. This is helpful when we want to run a lite actor on an edge device, and a big policy on a remote GPU server.

python3 examples/action_streamer.py --server

On a different terminal, you can also run it on a different machine and provide custom ip address and port number. e.g. --ip 100.10.23.23

python3 examples/action_streamer.py --client

2. Gym Env as action server

Say we have a simple env = gym.make('CartPole-v1') environment. Run example: python3 examples/action_cartpole_env.py

We can use agentlace to run the environment as a server, and the client can send action to the server in a distributed manner. Meanwhile, we still retain the gym API on the client and server side.

# Run the server first
python3 examples/action_cartpole_env.py --server
# Run the client on a different terminal
python3 examples/action_cartpole_env.py --client

3. Async learner-actor with Gym RL env

Requires jax, jaxrl_m, mujuco-py as dependencies.

This showcases how we can enable distributed training for RL applications. The learner can be run on a remote GPU server, while the actor can be run on a edge device. Off-policy RL algorithim (SAC) is used in this example.

# Indicate --learner or --actor mode, no tag means async multithreaded mode
# provide --ip for remote connection, default is localhost
python3 examples/async_learner_actor.py

More option flags:

• --env: gym env name, default is HalfCheetah-v4
• --learner: run learner mode
• --actor: run actor mode
• --ip: ip address of the remote server
• --render: render the gym env
• --use_traj_buffer: use trajectory buffer instead of replay buffer
• --rlds_log_dir: directory to save the tfrecords for RLDS

NOTE: rlds logger requires installation of oxe_envlogger

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Architecture

There are three types of server-client main types of classes for user to use, according to their application. Functional programming is mainly used as the API design. User can define their own callback function to process the data. There are 3 primary modes: action, inference, trainer.

1. Action service (edge device) as server: agentlace.ActionServer and agentlace.ActionClient
   • ActionServer provides observation to client, and execute action sent by client
   • ActionClient provides action to server, and get observation from server

For a Reinforcement learning setting, this action server can be considered as a EnvServer, which takes in action and return obs. The term of ActionServer is to make it more general for other applications other than RL.

Multi-clients can connect to the action server. client can call obs, act impl, and server can call publish_obs method. The method is shown in the diagram below.

graph LR
A[Clients] -- "obs()" --> B((Action Server))
A -- "act()" --> B
B -- "publish_obs()" --> A

2. Trainer compute as server: agentlace.TrainerServer and agentlace.TrainerClient
   • TrainerClient provides consistent datastore update to server and gets new network

This supports distributed datastore, and enable multiple clients to send data to server. The server can then publish the new network to all clients.

Clients keep their own instance of their datastore, call the update() method to provide the latest datastore update to the trainer server via an internal datastore (ReplayBuffer). The trainer retrieve data from the datastore and provide the trained network to client via publish_network() method

graph LR
A[ActorA - client] -- "update()" --> B((Learner - \n Trainer Server))
B -- "publish_network()" --> A
A -- "send_request()" --> B
G[ActorB - client] <--> B

1. Inference compute as server: agentlace.InferenceServer and agentlace.InferenceClient
   • InferenceClient provides observation to server and gets prediction

Multi-client to call inference compute. client can call the call method

graph LR
A[Client 1] -- "call()" --> B((Inference Server))
C[Client 2] -- "call()" --> B

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Example Usage

For more examples, please refer to the test scripts in agentlace/tests/ and examples.

1. A RL Env as Action Server

The environment can send observations to a remote client. The client, in turn, can provide actions to the environment server. This uses the agentlace.ActionServer and agentlace.ActionClient classes.

Click to show code example

GPU Compute as client

model = load_model()
agent = agentlace.ActionClient('localhost', 6379, task_id='mnist', config=agent_config)

for _ in range(100):
    observation = agent.obs()
    prediction = model.predict(observation)
    agent.act("send", prediction)

Edge device as server

def action_callback(key, action):
    # TODO: process action here
    return {"status": "received"}

def observation_callback(keys):
    # TODO: return the desired observations here
    return {"cam1": "some_value"}

config = agentlace.ActionConfig(port_number=6379, action_keys=['move'], observation_keys=['cam1'])
agent_server = agentlace.ActionServer(config, observation_callback, action_callback)
agent_server.start()

2. Remote Training Example for an RL Application

A remote trainer can access the datastore updated by devices/actors and sends updated network back. The actors then updates its model with these new network. This uses the agentlace.TrainerServer and agentlace.TrainerClient classes.

Click to show code example

Client

env = gym.make('CartPole-v0')
observation = env.reset()

# create data store and register to trainer client
data_store = agentlace.data.ReplayBuffer(capacity=2)
trainer_client = agentlace.TrainerClient(
    "agent1", 'localhost', TrainerConfig(), data_store)

agent = make_agent()  # Arbitrary RL agent

# register callback function to receive new weights
def _recv_weights(new_weights):
    nonlocal agent
    agent.update_weights(new_weights)

trainer_client.recv_network_callback(_recv_weights)

# automatically update datastore every 10 seconds
trainer.client.start_async_update(interval=10)

# Run training steps
while True:
    action = agent.get_action(observation)
    _data_point = env.step(action)
    data_store.insert(_data_point)

Trainer (Remote compute)

trainer_server = agentlace.TrainerServer(agentlace.TrainerConfig())

# create datastore in server
data_store = agentlace.data.ReplayBuffer(capacity=2)
trainer_server.register_data_store("agent1", data_store)
trainer_server.start(threaded=True)

while True:
    time.sleep(10) # every 10 seconds
    _data = data_store.sample(...) # sample data from datastore
    new_weights = AGENT.train(_data)
    trainer_server.publish_network(new_weights)

3. Agent as client and inference as server

This uses the agentlace.InferenceServer and agentlace.InferenceClient classes. This is useful for low power edge devices that cannot run inference locally.

Click to show code example

Inference server

def predict(payload):
    # TODO: do some prediction based on payload
    return {"prediction": "some_value"}

inference_server = agentlace.InferenceServer(port_num=6379)
inference_server.register_interface("voice_reg", predict)
inference_server.register_interface("face_reg", predict)
inference_server.start()

Client

client = agentlace.InferenceClient('localhost', 6379)
res = client.call("voice_reg", {"audio": "serialized_audio"})

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Additional Notes

• Run test cases to make sure everything is working as expected.

python3 agentlace/tests/test_action.py
python3 agentlace/tests/test_inference.py
python3 agentlace/tests/test_trainer.py
python3 agentlace/tests/test_tfds.py

# Run all tests
python3 agentlace/tests/test_all.py

# Run specific test
pytest-3 agentlace/tests/test_data_store.py

• The current implementation mainly uses zeromq as communication protocol, it should be easy to extend it to support other protocols such as grpc. (TODO: impl abstract function when there is a need)