machinectl does not support any sensible form of pipe to the child
process, so it is necessary to bypass it when talking to a systemd
container (see systemd/systemd#8850).
This can also form the basis for issue #223, where the post-fork
namespace switching dance required to connect to the Pythonless
container will be the same.
mitogen/master.py:
Annotate forwarded log entries with their original source, logger
name, and message.
ansible:
mark stderr in red with -vvv
Tempting to make this appaer 100% of the time, but some crappy
bashrcs may cause lots of junk to be printed.
This change blocks off 2 common scenarios where a race condition is
upgraded to a hang, when the library could internally do better.
* Since we don't know whether the receiver of a `reply_to` is expecting
a raw or pickled message, and since in the case of a raw reply, there
is no way to signal "dead" to the receiver, override the reply_to
field to explicitly mark a message as dead using a special handle.
This replaces the serialized _DEAD sentinel value with a slightly
neater interface, in the form of the reserved IS_DEAD handle, and
enables an important subsequent change: when a context cannot route a
message, it can send a generic 'dead' reply back towards the message
source, ensuring any sleeping thread is woken with ChannelError.
The use of this field could potentially be extended later on if
additional flags are needed, but for now this seems to suffice.
* Teach Router._invoke() to reply with a dead message when it receives a
message for an invalid local handle.
* Teach Router._async_route() to reply with a dead message when it
receives an unroutable message.
Presently there is still no mechanism to add :attr:`tty_stream` to the
multiplexer after connection is successful, but for now it's not
expected that anything will be logged to it anyway.
Closes#148.
Now Connection.close() *must* be called in the worker, to ensure the
reference count for a context drops correctly.
Remove 'discriminator' for now, I'm not using it for testing any more
and it complicated this code.
This code is a car crash, it needs rewritten again. Ideally some/most of
this behaviour could live on services.DeduplicatingService somehow, but
I couldn't come up with a sensible design.
Lots of "invalid handle: ..., 102" messages started appearing during
exit recently because ordering changed slightly, and local handles were
sent _DEAD even though the broker loop was still progressing through
shutdown.
The "shutdown" event is too early to close handles: it is the start of
the grace period where streams and downstream contexts can finish up any
work and deliver buffered data, including FORWARD_LOG messages that
haven't arrived yet.
So instead,
- move the _DEAD logic to the "exit" event,
- get rid of Context.on_shutdown() entirely, it's been unused for over
a month,
- get rid of the "crash" event, since it always fires prior to "exit",
and its only use was to send _DEAD to local handles, which now happens
during exit anyway.
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.
David Wilson