env.py

from pathlib import Path
import subprocess
import sys
import gymnasium as gym
from gymnasium import spaces
import numpy as np
from huggingface_hub import snapshot_download
import os
import signal
snapshot_download("lerobot/unitree-g1-mujoco")


def make_env(n_envs=1, use_async_envs=False, **kwargs):

    # define run_sim FIRST
    repo_dir = Path(__file__).parent
    run_sim = repo_dir / "run_sim.py"

    print("=" * 60)
    print("launching run_sim.py as subprocess")
    print("path:", run_sim)
    print("=" * 60)

    # now you can launch it
    proc = subprocess.Popen([sys.executable, str(run_sim)])
    print(f"simulator started as pid={proc.pid}")

    class DummyEnv(gym.Env):
        metadata = {"render_modes": []}

        def __init__(self, process):
            super().__init__()
            self.process = process
            self.action_space = spaces.Box(-1, 1, shape=(1,), dtype=np.float32)
            self.observation_space = spaces.Box(-1, 1, shape=(1,), dtype=np.float32)

        def reset(self, seed=None, options=None):
            super().reset(seed=seed, options=options)
            obs = np.zeros(1, dtype=np.float32)
            info = {}
            return obs, info

        def step(self, action):
            return np.zeros(1, dtype=np.float32), 0.0, False, False, {}

        def close(self):
            pass

        def kill_sim(self):
            if self.process.poll() is None:
                print("killing simulator subprocess...")
                self.process.terminate()
                try:
                    self.process.wait(timeout=2)
                except subprocess.TimeoutExpired:
                    print("force killing simulator subprocess...")
                    self.process.kill()

    return DummyEnv(proc)