def test_initializer(cleanup_only):
def init(dirname):
with open(os.path.join(dirname, str(os.getpid())), "w") as f:
print("hello", file=f)
with tempfile.TemporaryDirectory() as dirname:
num_processes = 4
pool = Pool(processes=num_processes,
initializer=init,
initargs=(dirname, ))
assert len(os.listdir(dirname)) == 4
pool.terminate()
def test_maxtasksperchild(cleanup_only):
def f(args):
return os.getpid()
pool = Pool(5, maxtasksperchild=1)
assert len(set(pool.map(f, range(20)))) == 20
def test_initialize_ray(cleanup_only):
def getpid(args):
return os.getpid()
def check_pool_size(pool, size):
args = [tuple() for _ in range(size)]
assert len(set(pool.map(getpid, args))) == size
# Check that starting a pool starts ray if not initialized.
pool = Pool(processes=2)
assert ray.is_initialized()
assert int(ray.state.cluster_resources()["CPU"]) == 2
check_pool_size(pool, 2)
ray.shutdown()
# Check that starting a pool doesn't affect ray if there is a local
# ray cluster running.
ray.init(num_cpus=3)
assert ray.is_initialized()
pool = Pool(processes=2)
assert int(ray.state.cluster_resources()["CPU"]) == 3
check_pool_size(pool, 2)
ray.shutdown()
# Check that trying to start a pool on an existing ray cluster throws an
# error if there aren't enough CPUs for the number of processes.
ray.init(num_cpus=1)
assert ray.is_initialized()
with pytest.raises(ValueError):
Pool(processes=2)
assert int(ray.state.cluster_resources()["CPU"]) == 1
ray.shutdown()
# Use different numbers of CPUs to distinguish between starting a local
# ray cluster and connecting to an existing one.
init_cpus = 2
start_cpus = 3
# Start a ray cluster in the background.
subprocess.check_output(
["ray", "start", "--head", "--num-cpus={}".format(start_cpus)])
# Check that starting a pool still starts ray if RAY_ADDRESS not set.
pool = Pool(processes=init_cpus)
assert ray.is_initialized()
assert int(ray.state.cluster_resources()["CPU"]) == init_cpus
check_pool_size(pool, init_cpus)
ray.shutdown()
# Check that starting a pool connects to a running ray cluster if
# ray_address is passed in.
pool = Pool(ray_address="auto")
assert ray.is_initialized()
assert int(ray.state.cluster_resources()["CPU"]) == start_cpus
check_pool_size(pool, start_cpus)
ray.shutdown()
# Set RAY_ADDRESS, so pools should connect to the running ray cluster.
os.environ["RAY_ADDRESS"] = "auto"
# Check that starting a pool connects to a running ray cluster if
# RAY_ADDRESS is set.
pool = Pool()
assert ray.is_initialized()
assert int(ray.state.cluster_resources()["CPU"]) == start_cpus
check_pool_size(pool, start_cpus)
ray.shutdown()
# Check that trying to start a pool on an existing ray cluster throws an
# error if there aren't enough CPUs for the number of processes.
with pytest.raises(Exception):
Pool(processes=start_cpus + 1)
assert int(ray.state.cluster_resources()["CPU"]) == start_cpus
ray.shutdown()
# Clean up the background ray cluster.
subprocess.check_output(["ray", "stop"])
def pool_4_processes():
pool = Pool(processes=4)
yield pool
pool.terminate()
ray.shutdown()