Move all details of broker/router setup out of connection.py, instead
deferring it to a WorkerModel class exported by process.py via
get_worker_model(). The running strategy can override the configured
worker model via _get_worker_model().
ClassicWorkerModel is installed by default, which implements the
extension's existing process model.
Add optional support for the third party setproctitle module, so
children have pretty names in ps output.
Add optional support for per-CPU multiplexers to classic runs.
This implements the first edition of Connection Delegation, where
delegating connection establishment is initially single-threaded.
ansible_mitogen/strategy.py:
ansible_mitogen/plugins/connection/*:
Begin splitting connection.Connection into subclasses, exposing them
directly as "mitogen_ssh", "mitogen_local", etc. connection types.
This is far from removing strategy.py, but it's a tiny start.
ansible_mitogen/connection.py:
* config_from_play_context() and config_from_host_vars() build up a
huge dictionary containing either more or less PlayContext contents,
or our best attempt at reconstructing a host's connection config
from its hostvars, where that config is not the current
WorkerProcess target.
They both produce the same format with the same keys, allowing
remaining code to have a single input format.
These dicts contain fields named after how Ansible refers to them,
e.g. "sudo_exe".
* _config_from_via() parses a basic connection specification like
"username@inventory_name" into one of the aforementioned dicts.
* _stack_from_config() produces a list of dicts describing the order
in which (Mitogen) connections should be established, such that each
element is proxied via= the previous element. The dicts produced by
this function use Mitogen keyword arguments, the former di.
These dicts contain fields named after how Mitogen refers to them,
e.g. "sudo_path".
* Pass the stack to ContextService, which is responsible for actual
setup of the full chain.
ansible_mitogen/services.py:
Teach get() to walk the supplied stack, establishing each connection
in turn, creating refounts for it before continuing.
TODO: refcounting is broken in a variety of cases.
Alex Willmer