How can I test to see whether gevent monkey patching is active? - gevent

Question

Is there any "official" way my library can test to see whether gevent monkey patching has been activated?

Answer 1

I don't know about an official way, but here's a way.
Notice os.fork changes when it gets monkey patched:
>>> import os
>>> os.fork
<built-in function fork>
>>> import gevent.monkey; gevent.monkey.patch_all()
>>> os.fork
<function fork at 0x100535140>
And notice what gevent.fork is:
>>> import gevent
>>> gevent.fork
<function fork at 0x100535140>
So, when monkey patching all (or just os):
>>> is_monkeypatched = gevent.fork == os.fork

Answer 2

See the docs.
from gevent import monkey
monkey.is_module_patched('socket')

Answer 3

The short answer is "no" (and, obviously, one would expect to see an API provided in the docs if there were).
The longer answer is "mostly", using monkey.saved. Checking the source you can see that effectively all the usual patching updates this dictionary with references to the original items, so they can be retrieved using monkey.get_original(). This isn't official if you believe officialness requires documentation, but it doesn't seem to be meant as an internal API despite it not being exported in monkey.__all__.
If by your question you mean simply "has any monkey-patching occurred?" then you could just test if monkey.saved: ....
If you mean "has module XXX been monkey-patched?" then you could test for the appropriate name, e.g. if "threading" in monkey.saved: ...
For reference, after doing a monkey.patch_all() here's what you'd see in there. (Note that patch_all() doesn't actually patch everything. It leaves out subprocess, sys, and Event by default, so I included them below.)
>>> import os, gevent
>>> os.name, gevent.__version__
('posix', '1.0.1')
>>> from gevent import monkey
>>> monkey.patch_all(subprocess=True, sys=True, Event=True)
>>> monkey.saved.keys()
['socket', 'thread', 'ssl', 'gevent.socket', 'subprocess', 'sys', 'threading', 'time', 'os', 'select']