Echo Environment

A simple test environment that echoes back messages. Perfect for testing the env APIs as well as demonstrating environment usage patterns.

Quick Start

The simplest way to use the Echo environment is through the EchoEnv class:

from envs.echo_env import EchoAction, EchoEnv

try:
    # Create environment from Docker image
    echo_env = EchoEnv.from_docker_image("echo-env:latest")

    # Reset
    result = echo_env.reset()
    print(f"Reset: {result.observation.echoed_message}")

    # Send multiple messages
    messages = ["Hello, World!", "Testing echo", "Final message"]

    for msg in messages:
        result = echo_env.step(EchoAction(message=msg))
        print(f"Sent: '{msg}'")
        print(f"  → Echoed: '{result.observation.echoed_message}'")
        print(f"  → Length: {result.observation.message_length}")
        print(f"  → Reward: {result.reward}")

finally:
    # Always clean up
    echo_env.close()

That's it! The EchoEnv.from_docker_image() method handles:

• Starting the Docker container


• Waiting for the server to be ready


• Connecting to the environment


• Container cleanup when you call close()




Building the Docker Image



Before using the environment, you need to build the Docker image:



From project root

docker build -t echo-env:latest -f src/envs/echo_env/server/Dockerfile .





Environment Details





Action


EchoAction: Contains a single field

• message (str) - The message to echo back




Observation


EchoObservation: Contains the echo response and metadata

• echoed_message (str) - The message echoed back


• message_length (int) - Length of the message


• reward (float) - Reward based on message length (length × 0.1)


• done (bool) - Always False for echo environment


• metadata (dict) - Additional info like step count




Reward


The reward is calculated as: message_length × 0.1

• "Hi" → reward: 0.2


• "Hello, World!" → reward: 1.3


• Empty message → reward: 0.0




Advanced Usage





Connecting to an Existing Server



If you already have an Echo environment server running, you can connect directly:



from envs.echo_env import EchoEnv

Connect to existing server

echo_env = EchoEnv(base_url="<ENV_HTTP_URL_HERE>")

Use as normal

result = echo_env.reset()
result = echo_env.step(EchoAction(message="Hello!"))



Note: When connecting to an existing server, echo_env.close() will NOT stop the server.



Development & Testing





Direct Environment Testing



Test the environment logic directly without starting the HTTP server:



From the server directory

python3 src/envs/echo_env/server/test_echo_env.py



This verifies that:

• Environment resets correctly


• Step executes actions properly


• State tracking works


• Rewards are calculated correctly




Running the Full Example



Run the complete example that demonstrates the full workflow:



python3 examples/local_echo_env.py



This example shows:

• Creating an environment from a Docker image


• Resetting and stepping through the environment


• Automatic cleanup with close()

Project Structure

echo_env/
├── __init__.py            # Module exports
├── README.md              # This file
├── client.py              # EchoEnv client implementation
├── models.py              # Action and Observation models
└── server/
    ├── __init__.py        # Server module exports
    ├── echo_environment.py  # Core environment logic
    ├── app.py             # FastAPI application
    ├── test_echo_env.py   # Direct environment tests
    └── Dockerfile         # Container image definition