Autodetect Docker API version

[skion]

This patch avoids the following error when connecting to Docker 1.11:

>>> docker.Client().containers(all=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/docker/api/container.py", line 85, in containers
    res = self._result(self._get(u, params=params), True)
  File "/usr/lib/python2.7/site-packages/docker/client.py", line 178, in _result
    self._raise_for_status(response)
  File "/usr/lib/python2.7/site-packages/docker/client.py", line 174, in _raise_for_status
    raise errors.APIError(e, response, explanation=explanation)
docker.errors.APIError: 400 Client Error: Bad Request ("client is newer than server (client API version: 1.24, server API version: 1.23)")

[shortdudey123]

Can you fix the tests?

[skion]

I'm not sure I can, as the Travis results don't reproduce for me and I seem to have unrelated test failures locally, maybe due to Docker 1.13?

$ docker -v
Docker version 1.13.0, build 49bf474

$ coverage run --source=diamond test.py
..EE..................................................No handlers could be found for logger "bernhard"
........................................................................................................................................................................................................................................................................................................................................................................................................................................
======================================================================
ERROR: test_should_get_containers (testmemory_docker.TestMemoryDockerCollector)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/home/pieter/workspace/python-diamond/src/collectors/memory_docker/test/testmemory_docker.py", line 81, in test_should_get_containers
    self.collector.collect()
  File "/home/pieter/workspace/python-diamond/src/collectors/memory_docker/memory_docker.py", line 34, in collect
    for c in docker.Client(version='auto').containers(all=True)
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/docker/client.py", line 56, in __init__
    self._auth_configs = auth.load_config()
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/docker/auth/auth.py", line 253, in load_config
    with open(config_file) as f:
AttributeError: __exit__

======================================================================
ERROR: test_should_open_all_cpuacct_stat (testmemory_docker.TestMemoryDockerCollector)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/home/pieter/workspace/python-diamond/src/collectors/memory_docker/test/testmemory_docker.py", line 67, in test_should_open_all_cpuacct_stat
    self.collector.collect()
  File "/home/pieter/workspace/python-diamond/src/collectors/memory_docker/memory_docker.py", line 34, in collect
    for c in docker.Client(version='auto').containers(all=True)
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/docker/client.py", line 56, in __init__
    self._auth_configs = auth.load_config()
  File "/home/pieter/.virtualenvs/python-diamond/local/lib/python2.7/site-packages/docker/auth/auth.py", line 253, in load_config
    with open(config_file) as f:
AttributeError: __exit__

----------------------------------------------------------------------
Ran 478 tests in 83.823s

[shortdudey123]

Probably need to fix the stubbing in the test
@patch.object(Client, 'containers', Mock(return_value=[])) and @patch.object(Client, 'containers')