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# distbuild/crashpoint.py -- user-controlled crashing
#
# Copyright (C) 2012, 2014 Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA..
'''Crash the application.
For crash testing, it's useful to easily induce crashes, to see how the
rest of the system manages. This module implements user-controllable
crashes. The code will be sprinkled with calls to the ``crash_point``
function, which crashes the process if call matches a set of user-defined
criteria.
The criteria consist of:
* a filename
* a function name
* a maximum call count
The criterion is fullfilled if ``crash_point`` is called from the named
function defined in the named file more than the given number of times.
Filename matching is using substrings (a filename pattern ``foo.py``
matches an actual source file path of
``/usr/lib/python2.7/site-packages/distbuild/foo.py``), but function
names must match exactly. It is not possible to match on class names
(since that information is not available from a traceback).
'''
import logging
import os
import sys
import traceback
detailed_logging = False
def debug(msg): # pragma: no cover
if detailed_logging:
logging.debug(msg)
class CrashCondition(object):
def __init__(self, filename, funcname, max_calls):
self.filename = filename
self.funcname = funcname
self.max_calls = max_calls
self.called = 0
def matches(self, filename, funcname):
if self.filename not in filename:
debug(
'crashpoint: filename mismatch: %s not in %s' %
(repr(self.filename), repr(filename)))
return False
if self.funcname != funcname:
debug(
'crashpoint: funcname mismatch: %s != %s' %
(self.funcname, funcname))
return False
debug('crashpoint: matches: %s %s' % (filename, funcname))
return True
def triggered(self, filename, funcname):
if self.matches(filename, funcname):
self.called += 1
return self.called >= self.max_calls
else:
return False
crash_conditions = []
def add_crash_condition(filename, funcname, max_calls):
crash_conditions.append(CrashCondition(filename, funcname, max_calls))
def add_crash_conditions(strings):
for s in strings:
words = s.split(':')
if len(words) != 3: # pragma: no cover
logging.error('Ignoring malformed crash condition: %s' % repr(s))
else:
add_crash_condition(words[0], words[1], int(words[2]))
def clear_crash_conditions():
del crash_conditions[:]
def crash_point(frame=None):
if frame is None:
frames = traceback.extract_stack(limit=2)
frame = frames[0]
filename, lineno, funcname, text = frame
for condition in crash_conditions:
if condition.triggered(filename, funcname):
logging.critical(
'Crash triggered from %s:%s:%s' % (filename, lineno, funcname))
sys.exit(255)
else:
debug(
'Crash not triggered by %s:%s:%s' %
(filename, lineno, funcname))
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