The OpenShift installer modifies /etc/resolv.conf then tests the new
resolver configuration, however, there was no mechanism to reload
resolv.conf in our reuseable interpreter.
https://github.com/openshift/openshift-ansible/blob/release-3.9/roles/openshift_web_console/tasks/install.yml#L137
This inserts an explicit call to res_init() for every new style
invocation, with an approximate cost of ~1usec on Linux since glibc
verifies resolv.conf has changed before reloading it.
There is little to be done for users of the thread-safe resolver APIs,
their state is hidden from us. If bugs like that manifest, whack-a-mole
style 'del sys.modules[thatmod]' patches may suffice.
Traced git log all the way back to beginning of time, and checked
Ansible versions starting Jan 2016. Zero clue where this came from, but
the convention suggests it came from Ansible at some point.
While adding support for non-new style module types, NewStyleRunner
began writing modules to a temporary file, and sys.argv was patched to
actually include the script filename. The argv change was never required
to fix any particular bug, and a search of the standard modules reveals
no argv users. Update argv[0] to be '', like an interactive interpreter
would have.
While fixing #210, new style runner began setting __file__ to the
temporary file path in order to allow apt.py to discover the Ansiballz
temporary directory. 5 out of 1,516 standard modules follow this
pattern, but in each case, none actually attempt to access __file__,
they just call dirname on it. Therefore do not write the contents of
file, simply set it to the path as it would exist, within a real
temporary directory.
Finally move temporary directory creation out of runner and into target.
Now a single directory exists for the duration of a run, and is emptied
by runner.py as necessary after each task invocation.
This could be further extended to stop rewriting non-new-style modules
in a with_items loop, but that's another step.
Finally the last bullet point in the documentation almost isn't a lie
again.
The module name comes from YAML via Jinja2.. it's always Unicode. Mixing
it into a temporary directory name produces a Unicode tempdir name,
which ends up in sys.argv via TemporaryArgv.
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.
* Use identical logic to select when stdout/stderr are merged, so
'stdout', 'stdout_lines', 'stderr', 'stderr_lines' contain the same
output before/after the extension.
* When stdout/stderr are merged, synthesize carriage returns just like
the TTY layer.
* Mimic the SSH connection multiplexing message on stderr. Not really
for user code, but so compare_output_test.sh needs fewer fixups.
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