[WIP] Docker connection plugin: allow to use Docker SDK for Python

[felixfontein]

SUMMARY

Allows the docker connection plugin to use Docker SDK for Python (aka docker-py) to communicate with the docker daemon, as opposed to using the docker CLI program. By default, it auto-detects whether to use the cli driver (i.e. use the docker CLI program) or the docker-py driver (i.e. the Docker SDK for Python), but the user can force the decision.

Fixes #17692.

There are currently some problems / things not implemented / working:

1. Up- and downloading files requires the files to fit into memory. It would be nice to stream them, to reduce memory usage. That will definitely require some more work.

2. sudo seems to work (haven't tested other become plugins), but pipelining right now isn't: it looks like passing larger amounts of data via stdin is not working, and it hangs after sending the data.

3. There's no way to configure how to talk to the docker daemon yet. That's the easiest to add :)

I also had to touch the synchronize module; it won't work with the new Docker SDK for Python driver, as opposed to the docker CLI driver, since there's no docker executable we can just use.

CC @ssbarnea

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

lib/ansible/plugins/connection/docker.py

[ansibot]

cc @DBendit @WojciechowskiPiotr @akshay196 @danihodovic @dariko @jwitko @kassiansun @tbouvet
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[felixfontein]

For me, right now, everything is working as follows:

Method	Python 2	Python 3
unix socket	✓	✓
SSH + unix	✓	✓
TCP	✓	✓
TCP + TLS	✓	✓

For SSH transport, it's hanging after sending the first block of input (maybe select doesn't work on that socket?). For TCP+TLS, I have no idea of how to indicate end of stdin , and I get a SSLError when reading.

[felixfontein]

I managed to fix SSH transport compatibility (the main problem was that select() for writing doesn't work because of paramiko/paramiko#695).

[felixfontein]

I have no idea how to fix the remaining problem (write connection shutdown for TCP+TLS); somehow related: urllib3/urllib3#1626.

[felixfontein]

Ok, I also got TCP+TLS support working, with a pretty ugly workaround though. Next I'll try to figure out why on earth CI produces these UnicodeEncodeErrors...

[Akasurde]

Hi @felixfontein, Thank you very much for your interest in Ansible. This plugin/module is no longer maintained in this repository and has been migrated to https://github.com/ansible-collections/community.general

If you have further questions please stop by IRC or the mailing list:

* IRC: #ansible on irc.freenode.net
* mailing list: https://groups.google.com/forum/#!forum/ansible-project

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