Ansible has no blocking services running, or really any service that
would have an outsized benefit from multiple IO waiters. Probably we
only need 1, but let's start with 2 just in case.
The previous method of spinning up a transient thread to import the
service pool in a child context could deadlock with use of the importer
on the main thread. Therefore wake the main thread to handle import for
us, and use a regular Receiver to buffer messages to the stub, which is
inherited rather than replaced by the real service pool.
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.
Split Stream into many, many classes
* mitogen.parent.Connection: Handles connection setup logic only.
* Maintain references to stdout and stderr streams.
* Manages TimerList timer to cancel connection attempt after
deadline
* Blocking setup code replaced by async equivalents running on the
broker
* mitogen.parent.Options: Tracks connection-specific options. This
keeps the connection class small, but more importantly, it is
generic to the future desire to build and execute command lines
without starting a full connection.
* mitogen.core.Protocol: Handles program behaviour relating to events
on a stream. Protocol performs no IO of its own, instead deferring
it to Stream and Side. This makes testing much easier, and means
libssh can reimplement Stream and Side to reuse MitogenProtocol
* mitogen.core.MitogenProtocol: Guts of the old Mitogen stream
implementtion
* mitogen.core.BufferedWriter: Guts of the old Mitogen buffered
transmit implementation, made generic
* mitogen.core.DelineatedProtocol: Guts of the old IoLogger, knows how
to split up input and pass it on to a
on_line_received()/on_partial_line_received() callback.
* mitogen.parent.BootstrapProtocol: Asynchronous equivalent of the old
blocking connect code. Waits for various prompts (MITO001 etc) and
writes the bootstrap using a BufferedWriter. On success, switches
the stream to MitogenProtocol.
* mitogen.core.Message: move encoding parts of MitogenProtocol out to
Message (where it belongs) and write a bunch of new tests for
pickling.
* The bizarre Stream.construct() is gone now, Option.__init__ is its
own constructor. Should fix many LGTM errors.
* Update all connection methods: Every connection method is updated to
use async logic, defining protocols as required to handle interactive
prompts like in SSH or su. Add new real integration tests for at least
doas and su.
* Eliminate manual fd management: File descriptors are trapped in file
objects at their point of origin, and Side is updated to use file
objects rather than raw descriptors. This eliminates a whole class of
bugs where unrelated FDs could be closed by the wrong component. Now
an FD's open/closed status is fused to it everywhere in the library.
* Halve file descriptor usage: now FD open/close state is tracked by
its file object, we don't need to duplicate FDs everywhere so that
receive/transmit side can be closed independently. Instead both sides
back on to the same file object. Closes#26, Closes#470.
* Remove most uses of dup/dup2: Closes#256. File descriptors are
trapped in a common file object and shared among classes. The
remaining few uses for dup/dup2 are as close to minimal as possible.
* Introduce mitogen.parent.Process: uniform interface for subprocesses
created either via mitogen.fork or the subprocess module. Remove all
the crap where we steal a pid from subprocess guts. Now we use
subprocess to manage its processes as it should be. Closes#169 by
using the new Timers facility to poll for a slow-to-exit subprocess.
* Fix su password race: Closes#363. DelineatedProtocol naturally
retries partially received lines, preventing the cause of the original
race.
* Delete old blocking IO utility functions
iter_read()/write_all()/discard_until().
Closes#26Closes#147Closes#169Closes#256Closes#363Closes#419Closes#470
There has always been a race in PushFileService since given a parent
asked to forward modules to two children via some intermediary:
interm = router.local()
c1 = router.local(via=interm)
c2 = router.local(via=interm)
service.propagate_to(c1, 'foo/bar.py')
service.propagate_to(c2, 'foo/bar.py')
Two calls will be emitted to 'interm':
PushFileService.store_and_forward(c1, 'foo/bar.py', [blob])
PushFileService.store(c2, 'foo/bar.py')
Which will be processed in-order up to the point where service pool
threads in 'interm' are woken to process the message.
While it is guaranteed store_and_forward() will be processed first, no
guarantee existed that its assigned pool thread would wake and take
_lock first, thus it was possible for forward() to win the race, and for
a request to arrive to forward a file that had not been placed in local
cache yet.
Here we get rid of SerializedInvoker entirely, as it is partially to
blame for hiding the race: SerializedInvoker can only ensure no two
messages are processed simultaneously, it cannot ensure the messages are
processed in their intended order.
Instead, teach forward() that it may be called before
store_and_forward(), and if that is the case, to place the forward
request on to _waiters alongside any local threads blocked in get().
[costapp]
ERROR! [pid 25135] 21:10:56.284733 E mitogen.ctx.ssh.35.200.203.48: mitogen: While calling no-reply method PushFileService.forward
Traceback (most recent call last):
File "master:/home/dmw/src/mitogen/mitogen/service.py", line 260, in _invoke
ret = method(**kwargs)
File "master:/home/dmw/src/mitogen/mitogen/service.py", line 718, in forward
self._forward(path, context)
File "master:/home/dmw/src/mitogen/mitogen/service.py", line 633, in _forward
stream = self.router.stream_by_id(context.context_id)
AttributeError: 'unicode' object has no attribute 'context_id'
^C [ERROR]: User interrupted execution
Minify-safe files are marked with a magical "# !mitogen: minify_safe"
comment anywhere in the file, which activates the minifier. The result
is naturally cached by ModuleResponder, therefore lru_cache is gone too.
Given:
import os, mitogen
@mitogen.main()
def main(router):
c = router.ssh(hostname='k3')
c.call(os.getpid)
router.sudo(via=c)
SSH footprint drops from 56.2 KiB to 42.75 KiB (-23.9%)
Ansible "shell: hostname" drops 149.26 KiB to 117.42 KiB (-21.3%)
Ansible modules were being resent continuously - but only the main
script module, and any custom modutils if any were present.
Wire footprint drops by ~1/3rd for a 500 task run of 'shell: hostname':
-rw-r--r-- 1 root root 584K Jan 31 22:06 500mito-before2
-rw-r--r-- 1 root root 434K Jan 31 22:04 500mito-filesbugonly
Alex Willmer