Don't set socket timeout if it's already disabled when streaming

[kevinfrommelt]

Problem

When streaming responses, socket timeouts are set to None to avoid read timeouts. Normally this is fine, but causes issues when using gevent. When using gevent, the socket class will be patched to be non-blocking (ie timeout == 0.0). If the timeout is set to None the socket becomes blocking again causing all greenlets to be blocked until the stream has finished.

Solution

The proposed fix is to only set the socket timeout if it isn't already disabled.

Reproduction Steps

test.py

from gevent import monkey
monkey.patch_all()

from datetime import datetime
import sys
import docker
import gevent

BUSYBOX = 'busybox:buildroot-2014.02'

def logs():
    for log in client.logs(container, stdout=True, stderr=True, stream=True):
        sys.stdout.write('[{}] log {}\n'.format(datetime.now().time(), log.strip()))
        sys.stdout.flush()

def ping():
    for i in xrange(0, 6):
        sys.stdout.write('[{}] ping {}\n'.format(datetime.now().time(), i))
        sys.stdout.flush()
        gevent.sleep(1)

if __name__ == '__main__':
    tls = docker.tls.TLSConfig(
        client_cert=(
            '/path/to/cert.pem',
            '/path/to/key.pem'
        ),
        verify='/path/to/ca.pem'
    )
    client = docker.Client(base_url='<docker_host>', tls=tls)

    client.pull(BUSYBOX)

    container = client.create_container(
        BUSYBOX,
        'sh -c "echo start; sleep 10; echo finish"',
        detach=True,
    )

    client.start(container)

    logs = gevent.spawn(logs)
    ping = gevent.spawn(ping)

    gevent.joinall([logs, ping], timeout=30)

Without these changes:

> python test.py
[10:02:20.749195] ping 0
[10:02:20.763980] log start
[10:02:30.751678] log finish
[10:02:30.772866] ping 1        <--- Gets blocked until logs have finished streaming (ie 10 secs)
[10:02:31.777957] ping 2
[10:02:32.781986] ping 3
[10:02:33.786190] ping 4
[10:02:34.790423] ping 5

With changes:

> python test.py
[10:02:48.505751] ping 0
[10:02:48.521915] log start
[10:02:49.510465] ping 1        <--- Allowed to run while streaming logs
[10:02:50.513776] ping 2
[10:02:51.517609] ping 3
[10:02:52.521996] ping 4
[10:02:53.526963] ping 5
[10:02:58.507385] log finish

[dnephin]

Code change looks good. How about a test to cover this case?

[kevinfrommelt]

@dnephin I added a couple unit tests. I think integration tests are going to be a bit trickier, as I'm not really sure how to replicate it without importing gevent and doing some patching. Let me know what you think, I can try playing around with some integration tests if you think we need it.

[dnephin]

LGTM

[shin-]

Thanks!