When a Broker() is running with install_watcher=True, arrange for only
one watcher thread to exist for each target thread, and to reset the
mapping of watchers to targets after process fork.
This is probably the last change I want to make to the watcher feature
before deciding to rip it out, it may be more trouble than it is worth.
Full output of failed test
```
ERROR: test_okay (__main__.FakeSshTest)
----------------------------------------------------------------------
Traceback (most recent call last):
File "tests/ssh_test.py", line 16, in test_okay
ssh_path=testlib.data_path('fakessh.py'),
File "/home/alex/src/mitogen/mitogen/master.py", line 650, in ssh
return self.connect('ssh', **kwargs)
File "/home/alex/src/mitogen/mitogen/parent.py", line 463, in connect
return self._connect(context_id, klass, name=name, **kwargs)
File "/home/alex/src/mitogen/mitogen/parent.py", line 449, in _connect
stream.connect()
File "/home/alex/src/mitogen/mitogen/ssh.py", line 104, in connect
super(Stream, self).connect()
File "/home/alex/src/mitogen/mitogen/parent.py", line 395, in connect
self._connect_bootstrap()
File "/home/alex/src/mitogen/mitogen/ssh.py", line 116, in
_connect_bootstrap
time.time() + 10.0):
File "/home/alex/src/mitogen/mitogen/parent.py", line 207, in
iter_read
(''.join(bits)[-300:],)
mitogen.core.StreamError: EOF on stream; last 300 bytes received:
'Usage: fakessh.py [options]\n\nfakessh.py: error: no such option: -o\n'
```
This eliminates the possibility of the filesystem and setup.py
diverging, as had happened with ansible_mitogen/connection/ vs
ansible_mitogen/connection.py
SSH command size: 439 (+4 bytes)
Preamble size: 8941 (no change)
This _increases_ the size of the first stage, but
- Eliminates one of the two remaining uses of `sys`
- Reads the preamble as a byte-string, no call `.encode()`
is needed on Python 3 before calling `_()`
SSH command size: 435 (-4 bytes)
Preamble size: 8962 (no change)
os.execl is the same as os.execv, but it take a variable number of
arguments instead of a single sequence.
SSH command size: 448 (-5 bytes)
Preamble size: 8941 (no change)
NB: The 'zip' alias was absent in Python 3.x, until Python 3.4. This
should change be reverted if Python 3.0, 3.2, or 3.3 support is
required.
This actually addresses multiple problems:
* Single-file programs were broken, since the fix introduced in
6931cc10c4 caused builtin_find_module()
to start indicating __main__ can always be loaded locally. That's
broken, and there might be more cases where the same problem will crop
up.
Since it was indicated __main__ could be loaded locally, the built-in
import machinery was allowed to attempt that (since we remove __main__
from sys.modules during bootstrap), which caused a safety check to
fire in the bowels of Python:
"Cannot re-init internal module %.200s"
* The check for presence of the whitelist was totally broken, since the
whitelist is never an empty list. Therefore 'self' was being returned
for every module, including extension modules like 'termios'.
I have hand-verified this does not break the fix for issue #113. I
looked at writing a test for that, but it requires a Docker container
(or similar) with an ancient version of Ansible installed. Will open a
separate ticket tracking this.
David Wilson