ResourceWarning: unclosed <socket.socket>

Hello.

It seems that in certain situations http socket isn’t properly closed.

/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/http/client.py:395: ResourceWarning: unclosed <socket.socket fd=7, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/Users/stas/Library/Containers/com.docker.docker/Data/s60>

Python 3.5.1 on OSX.

Can be reproduced with following script:

import unittest
import docker

# Warning depends on code layout, so add here some ballast classes,
# probably that puts GC in specific position.

class A(object):
    def __init__(self, node):
        print('A')

class B(object):
    def __init__(self, node):
        print('B')

class C(object):
    def __init__(self, node):
        print('C')

class D(object):
    def __init__(self, node):
        print('D')

class E(object):
    def __init__(self, node):
        print('E')

class SingleNodePartition(object):

    def __init__(self, node):
        self.node = node
        self.docker_api = docker.Client()

    def container_exec(self, node, command):
        exec_id = self.docker_api.exec_create(node, command, user='root')
        output = self.docker_api.exec_start(exec_id)

    def start(self):
        self.container_exec(self.node, "ls")
        self.container_exec(self.node, "ls")
        self.container_exec(self.node, "ls")
        self.container_exec(self.node, "ls")

class RecoveryTest(unittest.TestCase):

    def test_node_partition(self):
        failure = SingleNodePartition('node3')
        failure.start()

if __name__ == '__main__':
    unittest.main()

[caaespin]

Has this been fixed yet? I get this with docker py v4.2.0

[asottile-sentry]

as a workaround:

def docker_from_env() -> ContextManager[docker.DockerClient]:
    return contextlib.closing(docker.from_env())

usage:

with docker_from_env() as client:
    ...