To ensure a test process can successfully recreate an Ansible
MuxProcess, reset fork-inherited globals during disconnection.
There is basically no good place for this. Per the comments on #91, it
would be far better if the context's identity was tied to its router,
rather than some global variable.
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
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%)
os._exit() subverted calm shutdown, meaning unix.Listener never had a
chance to cleanup its socket.
Move unix.Listener socket cleanup into its class so it is automatic
during shutdown, rather than cutpasted for each consumer.
Disable the watcher thread in the MuxProcess, it is useless.
Add .sock extension to /tmp/mitogen_unix_*, so we can write a test.
In some scenarios, Ansible's worker seems to exit early, resulting in
EPIPE during .recv() or .send(). Log an error and gracefully disconnect
in that case.
The connection multiplexer can expect to not be scheduled at least until
every $forks worker processes has attempted a connection, so the backlog
must be able to hold every worker.
* ansible: use unicode_literals everywhere since it only needs to be
compatible back to 2.6.
* compat/collections.py: delete this entirely and rip out the parts of
functools that require it.
* Introduce serializable Kwargs dict subclass that translates keys to
Unicode on instantiation.
* enable_debug_logging() must set _v/_vv globals.
* cStringIO does not exist in 3.x.
* Treat IOLogger and LogForwarder input as latin-1.
* Avoid ResourceWarnings in first stage by explicitly closing fps.
* Fix preamble_size.py syntax errors.
The Context and Router APIs for constructing children and making
function calls should be available in every parent context, as user code
wants to have access to the same API.
accept() (per interface) returns a non-blocking socket because the
listener socket is in non-blocking mode, therefore it is pure scheduling
luck that a connecting-in child has a chance to write anything for the
top-level processs to read during the subsequent .recv().
A higher forks setting in ansible.cfg was enough to cause our luck to
run out, causing the .recv() to crashi with EGAIN, and the multiplexer
to respond to the handler's crash by calling its disconnect method. This
is why some reports mentioned ECONNREFUSED -- the listener really was
gone, because its Stream class had crashed.
Meanwhile since the window where we're waiting for the remote process to
identify itself is tiny, simply flip off O_NONBLOCK for the duration of
the connection handshake. Stream.accept() (via Side.__init__) will
reenable O_NONBLOCK for the descriptors it duplicates, so we don't even
need to bother turning this back off.
A better solution entails splitting Stream up into a state machine and
doing the handshake with non-blocking IO, but that isn't going to be
available until asynchronous connect is implemented. Meanwhile in
reality this solution is probably 100% fine.
David Wilson