__all__ = 'coroutine', 'iscoroutinefunction', 'iscoroutine'
import collections.abc
import functools
import inspect
import os
import sys
import traceback
import types
from . import base_futures
from . import constants
from . import format_helpers
from .log import logger
def _is_debug_mode():
# If you set _DEBUG to true, @coroutine will wrap the resulting
# generator objects in a CoroWrapper instance (defined below). That
# instance will log a message when the generator is never iterated
# over, which may happen when you forget to use "await" or "yield from"
# with a coroutine call.
# Note that the value of the _DEBUG flag is taken
# when the decorator is used, so to be of any use it must be set
# before you define your coroutines. A downside of using this feature
# is that tracebacks show entries for the CoroWrapper.__next__ method
# when _DEBUG is true.
return sys.flags.dev_mode or (not sys.flags.ignore_environment and
bool(os.environ.get('PYTHONASYNCIODEBUG')))
_DEBUG = _is_debug_mode()
class CoroWrapper:
# Wrapper for coroutine object in _DEBUG mode.
def __init__(self, gen, func=None):
assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
self.gen = gen
self.func = func # Used to unwrap @coroutine decorator
self._source_traceback = format_helpers.extract_stack(sys._getframe(1))
self.__name__ = getattr(gen, '__name__', None)
self.__qualname__ = getattr(gen, '__qualname__', None)
def __repr__(self):
coro_repr = _format_coroutine(self)
if self._source_traceback:
frame = self._source_traceback[-1]
coro_repr += f', created at {frame[0]}:{frame[1]}'
return f'<{self.__class__.__name__} {coro_repr}>'
def __iter__(self):
return self
def __next__(self):
return self.gen.send(None)
def send(self, value):
return self.gen.send(value)
def throw(self, type, value=None, traceback=None):
return self.gen.throw(type, value, traceback)
def close(self):
return self.gen.close()
@property
def gi_frame(self):
return self.gen.gi_frame
@property
def gi_running(self):
return self.gen.gi_running
@property
def gi_code(self):
return self.gen.gi_code
def __await__(self):
return self
@property
def gi_yieldfrom(self):
return self.gen.gi_yieldfrom
def __del__(self):
# Be careful accessing self.gen.frame -- self.gen might not exist.
gen = getattr(self, 'gen', None)
frame = getattr(gen, 'gi_frame', None)
if frame is not None and frame.f_lasti == -1:
msg = f'{self!r} was never yielded from'
tb = getattr(self, '_source_traceback', ())
if tb:
tb = ''.join(traceback.format_list(tb))
msg += (f'\nCoroutine object created at '
f'(most recent call last, truncated to '
f'{constants.DEBUG_STACK_DEPTH} last lines):\n')
msg += tb.rstrip()
logger.error(msg)
[docs]def coroutine(func):
"""Decorator to mark coroutines.
If the coroutine is not yielded from before it is destroyed,
an error message is logged.
"""
if inspect.iscoroutinefunction(func):
# In Python 3.5 that's all we need to do for coroutines
# defined with "async def".
return func
if inspect.isgeneratorfunction(func):
coro = func
else:
@functools.wraps(func)
def coro(*args, **kw):
res = func(*args, **kw)
if (base_futures.isfuture(res) or inspect.isgenerator(res) or
isinstance(res, CoroWrapper)):
res = yield from res
else:
# If 'res' is an awaitable, run it.
try:
await_meth = res.__await__
except AttributeError:
pass
else:
if isinstance(res, collections.abc.Awaitable):
res = yield from await_meth()
return res
coro = types.coroutine(coro)
if not _DEBUG:
wrapper = coro
else:
@functools.wraps(func)
def wrapper(*args, **kwds):
w = CoroWrapper(coro(*args, **kwds), func=func)
if w._source_traceback:
del w._source_traceback[-1]
# Python < 3.5 does not implement __qualname__
# on generator objects, so we set it manually.
# We use getattr as some callables (such as
# functools.partial may lack __qualname__).
w.__name__ = getattr(func, '__name__', None)
w.__qualname__ = getattr(func, '__qualname__', None)
return w
wrapper._is_coroutine = _is_coroutine # For iscoroutinefunction().
return wrapper
# A marker for iscoroutinefunction.
_is_coroutine = object()
def iscoroutinefunction(func):
"""Return True if func is a decorated coroutine function."""
return (inspect.iscoroutinefunction(func) or
getattr(func, '_is_coroutine', None) is _is_coroutine)
# Prioritize native coroutine check to speed-up
# asyncio.iscoroutine.
_COROUTINE_TYPES = (types.CoroutineType, types.GeneratorType,
collections.abc.Coroutine, CoroWrapper)
_iscoroutine_typecache = set()
def iscoroutine(obj):
"""Return True if obj is a coroutine object."""
if type(obj) in _iscoroutine_typecache:
return True
if isinstance(obj, _COROUTINE_TYPES):
# Just in case we don't want to cache more than 100
# positive types. That shouldn't ever happen, unless
# someone stressing the system on purpose.
if len(_iscoroutine_typecache) < 100:
_iscoroutine_typecache.add(type(obj))
return True
else:
return False
def _format_coroutine(coro):
assert iscoroutine(coro)
is_corowrapper = isinstance(coro, CoroWrapper)
def get_name(coro):
# Coroutines compiled with Cython sometimes don't have
# proper __qualname__ or __name__. While that is a bug
# in Cython, asyncio shouldn't crash with an AttributeError
# in its __repr__ functions.
if is_corowrapper:
return format_helpers._format_callback(coro.func, (), {})
if hasattr(coro, '__qualname__') and coro.__qualname__:
coro_name = coro.__qualname__
elif hasattr(coro, '__name__') and coro.__name__:
coro_name = coro.__name__
else:
# Stop masking Cython bugs, expose them in a friendly way.
coro_name = f'<{type(coro).__name__} without __name__>'
return f'{coro_name}()'
def is_running(coro):
try:
return coro.cr_running
except AttributeError:
try:
return coro.gi_running
except AttributeError:
return False
coro_code = None
if hasattr(coro, 'cr_code') and coro.cr_code:
coro_code = coro.cr_code
elif hasattr(coro, 'gi_code') and coro.gi_code:
coro_code = coro.gi_code
coro_name = get_name(coro)
if not coro_code:
# Built-in types might not have __qualname__ or __name__.
if is_running(coro):
return f'{coro_name} running'
else:
return coro_name
coro_frame = None
if hasattr(coro, 'gi_frame') and coro.gi_frame:
coro_frame = coro.gi_frame
elif hasattr(coro, 'cr_frame') and coro.cr_frame:
coro_frame = coro.cr_frame
# If Cython's coroutine has a fake code object without proper
# co_filename -- expose that.
filename = coro_code.co_filename or '<empty co_filename>'
lineno = 0
if (is_corowrapper and
coro.func is not None and
not inspect.isgeneratorfunction(coro.func)):
source = format_helpers._get_function_source(coro.func)
if source is not None:
filename, lineno = source
if coro_frame is None:
coro_repr = f'{coro_name} done, defined at {filename}:{lineno}'
else:
coro_repr = f'{coro_name} running, defined at {filename}:{lineno}'
elif coro_frame is not None:
lineno = coro_frame.f_lineno
coro_repr = f'{coro_name} running at {filename}:{lineno}'
else:
lineno = coro_code.co_firstlineno
coro_repr = f'{coro_name} done, defined at {filename}:{lineno}'
return coro_repr