This may come back to bite later, but in the meantime it avoids shipping
up to 12KiB of junk metadata for every single task invocation.
For detachment (aka. async), we must ensure the target has two types of
preloads completed (modules and module_utils files) before detaching.
And by "compatible" I mean "terrible". This does not implement async job
timeouts, but I'm not going to bother, upstream async implementation is
so buggy and inconsistent it resists even having its behaviour captured
in tests.
Closes#105.
References #155.
mitogen/service.py:
Refactor services to support individually exposed methods with
different security policies for each method.
- @mitogen.service.expose() to expose a method and set its policy
- @mitogen.service.arg_spec() to validate input.
- Require basic service message format to be a tuple of
`(method, kwargs)`, where kwargs is always a dict.
- Update DeduplicatingService to match the new scheme.
ansible_mitogen/connection.py:
- Rename 'method' to 'method_name' to disambiguate it from the
service.call()'s method= argument.
ansible_mitogen/planner.py:
- Generate an ID for every job, sync or not, and fetch job results
from JobResultService rather than via the initiating function
call's return value.
- Planner subclasses now get to select whether their Runner should
run in a forked process. The base implementation requests this if
the 'mitogen_isolation_mode=fork' task variable is present.
ansible_mitogen/runner.py:
Teach runners to deliver their result via JobResultService executing
in their indirect parent mux process.
ansible_mitogen/plugins/actions/mitogen_async_status.py:
Split the implementation up into methods, and more compatibly
emulate Ansible's existing output.
ansible_mitogen/process.py:
Mux processes now host JobResultService.
ansible_mitogen/services.py:
Update existing services to the new mitogen.service scheme, and
implement JobResultService:
* listen() method for synchronous jobs. planner.invoke() registers a
Sender with the service prior to invoking the job, then sleeps
waiting for the service to write the job result to the
corresponding Receiver.
* Non-blocking get() method for implementing mitogen_async_status
action.
* Child-accessible push() method for delivering task results.
ansible_mitogen/target.py:
New helpers for spawning a virginal subprocess on startup, from
which asynchronous and mitogen_task_isolation=fork jobs are forked.
Necessary to avoid a task inheriting potentially
polluted/monkey-patched parent environment, since remaining jobs
continue to run in the original child process.
docs/ansible.rst:
Add/merge/remove some behaviours/risks.
tests/ansible/integration:
New tests for forking/async.
Rather than assume any structure about the Python code:
* Delete the exit_json/fail_json monkeypatches.
* Patch SystemExit rather than a magic monkeypatch-thrown exception
* Setup fake cStringIO stdin, stdout, stderr and return those along with
SystemExit exit status
* Setup _ANSIBLE_ARGS as we used to, since we still want to override
that with '{}' to prevent accidental import hangs, but also provide
the same string via sys.stdin.
* Compile the module bytecode once and re-execute it for every
invocation. May change this back again later, once some benchmarks are
done.
* Remove the fixups stuff for now, it's handled by ^ above.
Should support any "somewhat new style" Python module, including those
that just give up and dump stuff to stdout directly.
Refactor planner.py to look a lot more like runner.py. This 'structural
cutpaste' looks messy -- probably we can simplify this code, even though
it's pretty simple already.
David Wilson