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python中利用tracekback跟踪栈以及打印异常信息

作者:  发布日期:2015-04-28 22:48:29
Tag标签:信息  
  • ?##sys.exc_info()
    返回 (type, value, traceback). type为异常类型, value为异常的参数(通常为异常错误的信息), traceback为跟踪回溯的对象.

        exc_type, exc_value, exc_traceback = sys.exc_info()
        print "*** print sys.exc_info:"
        print 'exc_type is: %s, exc_value is: %s, exc_traceback is: %s' % (exc_type, exc_value, exc_traceback)

    输出:

    *** print sys.exc_info:
    exc_type is: <type 'exceptions.IndexError'>, exc_value is: tuple index out of range, exc_traceback is: <traceback object at 0x7fee3b00eb48>

    traceback.print_tb(traceback[, limit[, file]])

    打印栈的跟踪信息. 如果省略limit, 将打印所有跟踪入口信息. file默认为std.err.

        print "*** print_tb:"
        traceback.print_tb(exc_traceback, limit=1, file=sys.stdout)

    输出:

    *** print_tb:
      File "t.py", line 13, in <module>
        mock()

    traceback.print_exception(type, value, traceback[, limit[, file]])

    打印异常信息. (type, value, traceback)为sys.exc_info()返回的元组.和print_tb不同的是:
    - 如果traceback不为空, 打印栈头信息(即最近被调用的信息).
    - 在栈的信息后打印异常类型和常的参数.
    - 如果是语法错误, 会打印对应的代码行数, 用”^”指明语法错误的位置.

        print "*** print_exception:"
        traceback.print_exception(exc_type, exc_value, exc_traceback, limit=2, file=sys.stdout)

    输出:

    *** print_exception:
    Traceback (most recent call last):
      File "t.py", line 13, in <module>
        mock()
      File "t.py", line 4, in mock
        lumberjack()
    IndexError: tuple index out of range

    traceback.print_exc([limit[, file]])

    print_exception(sys.exc_type, sys.exc_value, sys.exc_traceback, limit, file)的简写.

        print "*** print_exc:"
        traceback.print_exc()

    输出:

    *** print_exc:
    Traceback (most recent call last):
      File "t.py", line 13, in <module>
        mock()
      File "t.py", line 4, in mock
        lumberjack()
      File "t.py", line 7, in lumberjack
        bright_side_of_death()
      File "t.py", line 10, in bright_side_of_death
        return tuple()[1]
    IndexError: tuple index out of range

    traceback.format_exc([limit])

    类似于print_exc(limit), 但是返回字符串而不是输出到file.

        print "*** format_exc, first and last line:"
        formatted_lines = traceback.format_exc().splitlines()
        print formatted_lines[0]
        print formatted_lines[-1]

    输出:

    *** format_exc, first and last line:
    Traceback (most recent call last):
    IndexError: tuple index out of range

    traceback.format_exception(type, value, tb[, limit])

    格式化栈信息和异常信息. 返回一个列表, 包括代码文件和代码行, 以及异常信息.

        print "*** format_exception:"
        print repr(traceback.format_exception(exc_type, exc_value, exc_traceback))

    输出:

    ['Traceback (most recent call last):\n', '  File "t.py", line 13, in <module>\n    mock()\n', '  File "t.py", line 10, in mock\n    lumberjack()\n', '  File "t.py", line 4, in lumberjack\n    bright_side_of_death()\n', '  File "t.py", line 7, in bright_side_of_death\n    return tuple()[0]\n', 'IndexError: tuple index out of range\n']

    traceback.extract_tb(traceback[, limit])

    返回一个跟踪对象(traceback)的元组列表. 元组内容为(filename, line number, function name, text).

        print "*** extract_tb:"
        print repr(traceback.extract_tb(exc_traceback))

    输出:

    [('t.py', 13, '<module>', 'mock()'), ('t.py', 4, 'mock', 'lumberjack()'), ('t.py', 7, 'lumberjack', 'bright_side_of_death()'), ('t.py', 10, 'bright_side_of_death', 'return tuple()[1]')]

    traceback.extract_stack([f[, limit]])

    返回当前栈帧的原始跟踪(traceback)对象的信息, 格式和extract_tb一样, 元组内容为(filename, line number, function name, text).

        print "*** extract_stack:"
        print traceback.extract_stack()

    输出:

    *** extract_stack:
    [('t.py', 47, '<module>', 'print traceback.extract_stack()')]

    traceback.format_list(list)

    按照list对应的项, 返回一个元组列表, 形式为同extract_tb()或者extract_stack()返回的一样. 元组内容为(filename, line number, function name, text)
    将extract_tb()或者extract_stack()返回的list进行格式化.

    print traceback.format_list([('spam.py', 3, '<module>', 'spam.eggs()'), ('eggs.py', 42, 'eggs', 'return "bacon"')])

    输出:

    ['  File "spam.py", line 3, in <module>\n    spam.eggs()\n', '  File "eggs.py", line 42, in eggs\n    return "bacon"\n']
    

    traceback.format_tb(tb[, limit])

    format_list(extract_tb(tb, limit))的简写.

    traceback.format_stack([f[, limit]])

    format_list(extract_stack(f, limit))的简写

    traceback.tb_lineno(tb)

    返回traceback对象设置的行数

    实例

    import sys, traceback
    
    def mock():
        lumberjack()
    
    def lumberjack():
        bright_side_of_death()
    
    def bright_side_of_death():
        return tuple()[1]
    
    try:
        mock()
    except IndexError:
        exc_type, exc_value, exc_traceback = sys.exc_info()
        print "*** print sys.exc_info:"
        print 'exc_type is: %s, exc_value is: %s, exc_traceback is: %s' % (exc_type, exc_value, exc_traceback)
        print "-" *  100
    
        print "*** print_tb:"
        traceback.print_tb(exc_traceback, limit=1, file=sys.stdout)
        print "-" *  100
    
        print "*** print_exception:"
        traceback.print_exception(exc_type, exc_value, exc_traceback, limit=2, file=sys.stdout)
        print "-" *  100
    
        print "*** print_exc:"
        traceback.print_exc()
        print "-" *  100
    
        print "*** format_exc, first and last line:"
        formatted_lines = traceback.format_exc().splitlines()
        print formatted_lines[0]
        print formatted_lines[-1]
        print "-" *  100
    
        print "*** format_exception:"
        print repr(traceback.format_exception(exc_type, exc_value, exc_traceback))
        print "-" *  100
    
        print "*** extract_tb:"
        print repr(traceback.extract_tb(exc_traceback))
        print "-" *  100
    
        print "*** extract_stack:"
        print traceback.extract_stack()
        print "-" *  100
    
        print "*** format_tb:"
        print repr(traceback.format_tb(exc_traceback))
        print "-" *  100
    
        print "*** tb_lineno:", exc_traceback.tb_lineno
    
        print traceback.format_list([('spam.py', 3, '<module>', 'spam.eggs()'), ('eggs.py', 42, 'eggs', 'return "bacon"')])

    输出:

    *** print sys.exc_info:
    exc_type is: <type 'exceptions.IndexError'>, exc_value is: tuple index out of range, exc_traceback is: <traceback object at 0x7f7d659bab48>
    ----------------------------------------------------------------------------------------------------
    *** print_tb:
      File "t.py", line 13, in <module>
        mock()
    ----------------------------------------------------------------------------------------------------
    *** print_exception:
    Traceback (most recent call last):
      File "t.py", line 13, in <module>
        mock()
      File "t.py", line 4, in mock
        lumberjack()
    IndexError: tuple index out of range
    ----------------------------------------------------------------------------------------------------
    *** print_exc:
    Traceback (most recent call last):
      File "t.py", line 13, in <module>
        mock()
      File "t.py", line 4, in mock
        lumberjack()
      File "t.py", line 7, in lumberjack
        bright_side_of_death()
      File "t.py", line 10, in bright_side_of_death
        return tuple()[1]
    IndexError: tuple index out of range
    ----------------------------------------------------------------------------------------------------
    *** format_exc, first and last line:
    Traceback (most recent call last):
    IndexError: tuple index out of range
    ----------------------------------------------------------------------------------------------------
    *** format_exception:
    ['Traceback (most recent call last):\n', '  File "t.py", line 13, in <module>\n    mock()\n', '  File "t.py", line 4, in mock\n    lumberjack()\n', '  File "t.py", line 7, in lumberjack\n    bright_side_of_death()\n', '  File "t.py", line 10, in bright_side_of_death\n    return tuple()[1]\n', 'IndexError: tuple index out of range\n']
    ----------------------------------------------------------------------------------------------------
    *** extract_tb:
    [('t.py', 13, '<module>', 'mock()'), ('t.py', 4, 'mock', 'lumberjack()'), ('t.py', 7, 'lumberjack', 'bright_side_of_death()'), ('t.py', 10, 'bright_side_of_death', 'return tuple()[1]')]
    ----------------------------------------------------------------------------------------------------
    *** extract_stack:
    [('t.py', 47, '<module>', 'print traceback.extract_stack()')]
    ----------------------------------------------------------------------------------------------------
    *** format_tb:
    ['  File "t.py", line 13, in <module>\n    mock()\n', '  File "t.py", line 4, in mock\n    lumberjack()\n', '  File "t.py", line 7, in lumberjack\n    bright_side_of_death()\n', '  File "t.py", line 10, in bright_side_of_death\n    return tuple()[1]\n']
    ----------------------------------------------------------------------------------------------------
    *** tb_lineno: 13
    ['  File "spam.py", line 3, in <module>\n    spam.eggs()\n', '  File "eggs.py", line 42, in eggs\n    return "bacon"\n']
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