好吧,这是一种 缓慢的 方法。可以对其进行修改以监视局部变量的更改(仅按名称)。它是这样工作的:我们执行sys.settrace并在每个步骤中分析obj.attr的值。棘手的是,'line'
在执行行之前,我们会收到事件(执行了某些行)。因此,当我们注意到obj.attr发生了变化时,我们已经在下一行,并且无法获得前一行的帧(因为没有为每行复制帧,所以它们被修改了)。因此,在我保存traceback.format_stack
到的每个行事件中watcher.prev_st
,如果在下一次调用trace_command
值发生更改时,我们会将保存的堆栈跟踪打印到文件中。在每一行上保存回溯是相当昂贵的操作,因此您必须设置include
关键字指向您的项目目录列表(或只是项目的根目录),以免观察其他库的工作方式并浪费cpu。
import traceback
class Watcher(object):
def __init__(self, obj=None, attr=None, log_file='log.txt', include=[], enabled=False):
"""
Debugger that watches for changes in object attributes
obj - object to be watched
attr - string, name of attribute
log_file - string, where to write output
include - list of strings, debug files only in these directories.
Set it to path of your project otherwise it will take long time
to run on big libraries import and usage.
"""
self.log_file=log_file
with open(self.log_file, 'wb'): pass
self.prev_st = None
self.include = [incl.replace('\\','/') for incl in include]
if obj:
self.value = getattr(obj, attr)
self.obj = obj
self.attr = attr
self.enabled = enabled # Important, must be last line on __init__.
def __call__(self, *args, **kwargs):
kwargs['enabled'] = True
self.__init__(*args, **kwargs)
def check_condition(self):
tmp = getattr(self.obj, self.attr)
result = tmp != self.value
self.value = tmp
return result
def trace_command(self, frame, event, arg):
if event!='line' or not self.enabled:
return self.trace_command
if self.check_condition():
if self.prev_st:
with open(self.log_file, 'ab') as f:
print >>f, "Value of",self.obj,".",self.attr,"changed!"
print >>f,"###### Line:"
print >>f,''.join(self.prev_st)
if self.include:
fname = frame.f_code.co_filename.replace('\\','/')
to_include = False
for incl in self.include:
if fname.startswith(incl):
to_include = True
break
if not to_include:
return self.trace_command
self.prev_st = traceback.format_stack(frame)
return self.trace_command
import sys
watcher = Watcher()
sys.settrace(watcher.trace_command)
from watcher import watcher
import numpy as np
import urllib2
class X(object):
def __init__(self, foo):
self.foo = foo
class Y(object):
def __init__(self, x):
self.xoo = x
def boom(self):
self.xoo.foo = "xoo foo!"
def main():
x = X(50)
watcher(x, 'foo', log_file='log.txt', include =['C:/Users/j/PycharmProjects/hello'])
x.foo = 500
x.goo = 300
y = Y(x)
y.boom()
arr = np.arange(0,100,0.1)
arr = arr**2
for i in xrange(3):
print 'a'
x.foo = i
for i in xrange(1):
i = i+1
main()