def patch_module(target_module, source_module, items=None,
_warnings=None,
_notify_did_subscribers=True):
"""
patch_module(target_module, source_module, items=None)
Replace attributes in *target_module* with the attributes of the
same name in *source_module*.
The *source_module* can provide some attributes to customize the process:
* ``__implements__`` is a list of attribute names to copy; if not present,
the *items* keyword argument is mandatory.
* ``_gevent_will_monkey_patch(target_module, items, warn, **kwargs)``
* ``_gevent_did_monkey_patch(target_module, items, warn, **kwargs)``
These two functions in the *source_module* are called *if* they exist,
before and after copying attributes, respectively. The "will" function
may modify *items*. The value of *warn* is a function that should be called
with a single string argument to issue a warning to the user. If the "will"
function raises :exc:`gevent.events.DoNotPatch`, no patching will be done. These functions
are called before any event subscribers or plugins.
:keyword list items: A list of attribute names to replace. If
not given, this will be taken from the *source_module* ``__implements__``
attribute.
:return: A true value if patching was done, a false value if patching was canceled.
.. versionadded:: 1.3b1
"""
from gevent import events
if items is None:
items = getattr(source_module, '__implements__', None)
if items is None:
raise AttributeError('%r does not have __implements__' % source_module)
try:
__call_module_hook(source_module, 'will', target_module, items, _warnings)
_notify_patch(
events.GeventWillPatchModuleEvent(target_module.__name__, source_module,
target_module, items),
_warnings)
except events.DoNotPatch:
return False
for attr in items:
patch_item(target_module, attr, getattr(source_module, attr))
__call_module_hook(source_module, 'did', target_module, items, _warnings)
if _notify_did_subscribers:
# We allow turning off the broadcast of the 'did' event for the benefit
# of our internal functions which need to do additional work (besides copying
# attributes) before their patch can be considered complete.
_notify_patch(
events.GeventDidPatchModuleEvent(target_module.__name__, source_module,
target_module)
)
return True
def patch_sys(stdin=True, stdout=True, stderr=True):
"""
Patch sys.std[in,out,err] to use a cooperative IO via a
threadpool.
This is relatively dangerous and can have unintended consequences
such as hanging the process or `misinterpreting control keys`_
when :func:`input` and :func:`raw_input` are used. :func:`patch_all`
does *not* call this function by default.
This method does nothing on Python 3. The Python 3 interpreter
wants to flush the TextIOWrapper objects that make up
stderr/stdout at shutdown time, but using a threadpool at that
time leads to a hang.
.. _`misinterpreting control keys`: https://github.com/gevent/gevent/issues/274
"""
# test__issue6.py demonstrates the hang if these lines are removed;
# strangely enough that test passes even without monkey-patching sys
if PY3:
items = None
else:
items = set([('stdin' if stdin else None),
('stdout' if stdout else None),
('stderr' if stderr else None)])
items.discard(None)
items = list(items)
if not items:
return
from gevent import events
_notify_patch(events.GeventWillPatchModuleEvent('sys', None, sys,
items))
for item in items:
_patch_sys_std(item)
_notify_patch(events.GeventDidPatchModuleEvent('sys', None, sys))
