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"""The debug module contains utilities and functions for better
debugging Eventlet-powered applications."""
from __future__ import print_function
import os
import sys
import linecache
import re
import inspect
__all__ = ['spew', 'unspew', 'format_hub_listeners', 'format_hub_timers',
'hub_listener_stacks', 'hub_exceptions', 'tpool_exceptions',
'hub_prevent_multiple_readers', 'hub_timer_stacks',
'hub_blocking_detection']
_token_splitter = re.compile('\W+')
class Spew(object):
def __init__(self, trace_names=None, show_values=True):
self.trace_names = trace_names
self.show_values = show_values
def __call__(self, frame, event, arg):
if event == 'line':
lineno = frame.f_lineno
if '__file__' in frame.f_globals:
filename = frame.f_globals['__file__']
if (filename.endswith('.pyc') or
filename.endswith('.pyo')):
filename = filename[:-1]
name = frame.f_globals['__name__']
line = linecache.getline(filename, lineno)
else:
name = '[unknown]'
try:
src = inspect.getsourcelines(frame)
line = src[lineno]
except IOError:
line = 'Unknown code named [%s]. VM instruction #%d' % (
frame.f_code.co_name, frame.f_lasti)
if self.trace_names is None or name in self.trace_names:
print('%s:%s: %s' % (name, lineno, line.rstrip()))
if not self.show_values:
return self
details = []
tokens = _token_splitter.split(line)
for tok in tokens:
if tok in frame.f_globals:
details.append('%s=%r' % (tok, frame.f_globals[tok]))
if tok in frame.f_locals:
details.append('%s=%r' % (tok, frame.f_locals[tok]))
if details:
print("\t%s" % ' '.join(details))
return self
def spew(trace_names=None, show_values=False):
"""Install a trace hook which writes incredibly detailed logs
about what code is being executed to stdout.
"""
sys.settrace(Spew(trace_names, show_values))
def unspew():
"""Remove the trace hook installed by spew.
"""
sys.settrace(None)
def format_hub_listeners():
""" Returns a formatted string of the current listeners on the current
hub. This can be useful in determining what's going on in the event system,
especially when used in conjunction with :func:`hub_listener_stacks`.
"""
from eventlet import hubs
hub = hubs.get_hub()
result = ['READERS:']
for l in hub.get_readers():
result.append(repr(l))
result.append('WRITERS:')
for l in hub.get_writers():
result.append(repr(l))
return os.linesep.join(result)
def format_hub_timers():
""" Returns a formatted string of the current timers on the current
hub. This can be useful in determining what's going on in the event system,
especially when used in conjunction with :func:`hub_timer_stacks`.
"""
from eventlet import hubs
hub = hubs.get_hub()
result = ['TIMERS:']
for l in hub.timers:
result.append(repr(l))
return os.linesep.join(result)
def hub_listener_stacks(state=False):
"""Toggles whether or not the hub records the stack when clients register
listeners on file descriptors. This can be useful when trying to figure
out what the hub is up to at any given moment. To inspect the stacks
of the current listeners, call :func:`format_hub_listeners` at critical
junctures in the application logic.
"""
from eventlet import hubs
hubs.get_hub().set_debug_listeners(state)
def hub_timer_stacks(state=False):
"""Toggles whether or not the hub records the stack when timers are set.
To inspect the stacks of the current timers, call :func:`format_hub_timers`
at critical junctures in the application logic.
"""
from eventlet.hubs import timer
timer._g_debug = state
def hub_prevent_multiple_readers(state=True):
"""Toggle prevention of multiple greenlets reading from a socket
When multiple greenlets read from the same socket it is often hard
to predict which greenlet will receive what data. To achieve
resource sharing consider using ``eventlet.pools.Pool`` instead.
But if you really know what you are doing you can change the state
to ``False`` to stop the hub from protecting against this mistake.
"""
from eventlet.hubs import hub
hub.g_prevent_multiple_readers = state
def hub_exceptions(state=True):
"""Toggles whether the hub prints exceptions that are raised from its
timers. This can be useful to see how greenthreads are terminating.
"""
from eventlet import hubs
hubs.get_hub().set_timer_exceptions(state)
from eventlet import greenpool
greenpool.DEBUG = state
def tpool_exceptions(state=False):
"""Toggles whether tpool itself prints exceptions that are raised from
functions that are executed in it, in addition to raising them like
it normally does."""
from eventlet import tpool
tpool.QUIET = not state
def hub_blocking_detection(state=False, resolution=1):
"""Toggles whether Eventlet makes an effort to detect blocking
behavior in an application.
It does this by telling the kernel to raise a SIGALARM after a
short timeout, and clearing the timeout every time the hub
greenlet is resumed. Therefore, any code that runs for a long
time without yielding to the hub will get interrupted by the
blocking detector (don't use it in production!).
The *resolution* argument governs how long the SIGALARM timeout
waits in seconds. The implementation uses :func:`signal.setitimer`
and can be specified as a floating-point value.
The shorter the resolution, the greater the chance of false
positives.
"""
from eventlet import hubs
assert resolution > 0
hubs.get_hub().debug_blocking = state
hubs.get_hub().debug_blocking_resolution = resolution
if not state:
hubs.get_hub().block_detect_post()