def __init__(self, env_fns, start_method=None):
self.waiting = False
self.closed = False
n_envs = len(env_fns)
if start_method is None:
# Fork is not a thread safe method (see issue #217)
# but is more user friendly (does not require to wrap the code in
# a `if __name__ == "__main__":`)
forkserver_available = 'forkserver' in multiprocessing.get_all_start_methods(
)
start_method = 'forkserver' if forkserver_available else 'spawn'
ctx = multiprocessing.get_context(start_method)
self.remotes, self.work_remotes = zip(
*[ctx.Pipe(duplex=True) for _ in range(n_envs)])
self.processes = []
for work_remote, remote, env_fn in zip(self.work_remotes, self.remotes,
env_fns):
args = (work_remote, remote, CloudpickleWrapper(env_fn))
# daemon=True: if the main process crashes, we should not cause things to hang
process = ctx.Process(target=_worker, args=args, daemon=True)
process.start()
self.processes.append(process)
work_remote.close()
self.remotes[0].send(('get_spaces', None))
observation_space, action_space = self.remotes[0].recv()
VecEnv.__init__(self, len(env_fns), observation_space, action_space)
def __init__(self, env_fns, start_method=None):
self.waiting = False
self.closed = False
n_envs = len(env_fns)
# In some cases (like on GitHub workflow machine when running tests),
# "forkserver" method results in an "connection error" (probably due to mpi)
# We allow to bypass the default start method if an environment variable
# is specified by the user
if start_method is None:
start_method = os.environ.get("DEFAULT_START_METHOD")
# No DEFAULT_START_METHOD was specified, start_method may still be None
if start_method is None:
# Fork is not a thread safe method (see issue #217)
# but is more user friendly (does not require to wrap the code in
# a `if __name__ == "__main__":`)
forkserver_available = 'forkserver' in multiprocessing.get_all_start_methods(
)
start_method = 'forkserver' if forkserver_available else 'spawn'
ctx = multiprocessing.get_context(start_method)
self.remotes, self.work_remotes = zip(
*[ctx.Pipe(duplex=True) for _ in range(n_envs)])
self.processes = []
for work_remote, remote, env_fn in zip(self.work_remotes, self.remotes,
env_fns):
args = (work_remote, remote, CloudpickleWrapper(env_fn))
# daemon=True: if the main process crashes, we should not cause things to hang
process = ctx.Process(target=_worker, args=args, daemon=True) # pytype:disable=attribute-error
process.start()
self.processes.append(process)
work_remote.close()
self.remotes[0].send(('get_spaces', None))
observation_space, action_space = self.remotes[0].recv()
VecEnv.__init__(self, len(env_fns), observation_space, action_space)