server/app.py

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

"""
FastAPI application for the Python Env Environment.

This module creates an HTTP server that exposes the PythonEnvironment
over HTTP and WebSocket endpoints, compatible with EnvClient.

Endpoints:
    - POST /reset: Reset the environment
    - POST /step: Execute an action
    - GET /state: Get current environment state
    - GET /schema: Get action/observation schemas
    - WS /ws: WebSocket endpoint for persistent sessions

Usage:
    # Development (with auto-reload):
    uvicorn server.app:app --reload --host 0.0.0.0 --port 8000

    # Production:
    uvicorn server.app:app --host 0.0.0.0 --port 8000 --workers 4

    # Or run directly:
    python -m server.app
"""

from fastapi.routing import APIRoute

try:
    from openenv.core.env_server.http_server import create_app
except Exception as e:  # pragma: no cover
    raise ImportError(
        "openenv is required for the web interface. Install dependencies with '\n    uv sync\n'"
    ) from e

try:
    from ..models import (
        HealthResponse,
        MetricsResponse,
        PythonAction,
        PythonObservation,
        PythonState,
        TaskListResponse,
    )
    from .python_env_environment import (
        get_environment,
        get_current_state,
        get_health_response,
        get_metrics_response,
        get_tasks_response,
    )
except ImportError:
    from models import (  # type: ignore
        HealthResponse,
        MetricsResponse,
        PythonAction,
        PythonObservation,
        PythonState,
        TaskListResponse,
    )
    from server.python_env_environment import (  # type: ignore
        get_environment,
        get_current_state,
        get_health_response,
        get_metrics_response,
        get_tasks_response,
    )


# Create the app with web interface and README integration
app = create_app(
    get_environment,
    PythonAction,
    PythonObservation,
    env_name="python_env",
    max_concurrent_envs=1,  # the shared environment is intended for one active session
)


def _remove_get_route(path: str) -> None:
    app.router.routes = [
        route
        for route in app.router.routes
        if not (
            isinstance(route, APIRoute)
            and route.path == path
            and "GET" in route.methods
        )
    ]


_remove_get_route("/health")
_remove_get_route("/state")


@app.get("/health", response_model=HealthResponse, tags=["Health"])
async def health() -> HealthResponse:
    return get_health_response()


@app.get("/state", response_model=PythonState, tags=["State Management"])
async def state() -> PythonState:
    return get_current_state()


@app.get("/tasks", response_model=TaskListResponse, tags=["Environment Info"])
async def tasks() -> TaskListResponse:
    return get_tasks_response()


@app.get("/metrics", response_model=MetricsResponse, tags=["Environment Info"])
async def metrics() -> MetricsResponse:
    return get_metrics_response()


def main(host: str = "0.0.0.0", port: int = 8000):
    """
    Entry point for direct execution via uv run or python -m.

    This function enables running the server without Docker:
        uv run --project . server
        uv run --project . server --port 8001
        python -m python_env.server.app

    Args:
        host: Host address to bind to (default: "0.0.0.0")
        port: Port number to listen on (default: 8000)

    For production deployments, consider using uvicorn directly with
    multiple workers:
        uvicorn python_env.server.app:app --workers 4
    """
    import uvicorn

    uvicorn.run(app, host=host, port=port)


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser()
    parser.add_argument("--port", type=int, default=8000)
    args = parser.parse_args()
    main(port=args.port)