关于python:decorator打印函数调用详细信息-参数名称和有效值

Decorator to print function call details - parameters names and effective values

我想创建一个函数，作为另一个函数的修饰器，它将打印该函数调用的详细信息-参数名称和有效值。我目前的实现就是这样。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

def describeFuncCall(func):
'''Decorator to print function call details - parameters names and effective values'''
def wrapper(*func_args, **func_kwargs):
print 'func_code.co_varnames =', func.func_code.co_varnames
print 'func_code.co_argcount =', func.func_code.co_argcount
print 'func_args =', func_args
print 'func_kwargs =', func_kwargs
params = []
for argNo in range(func.func_code.co_argcount):
argName = func.func_code.co_varnames[argNo]
argValue = func_args[argNo] if argNo < len(func_args) else func.func_defaults[argNo - func.func_code.co_argcount]
params.append((argName, argValue))
for argName, argValue in func_kwargs.items():
params.append((argName, argValue))
params = [ argName + ' = ' + repr(argValue) for argName, argValue in params]
print(func.__name__ + ' ( ' + ', '.join(params) + ' )')
return func(*func_args, **func_kwargs)
return wrapper

@describeFuncCall
def test(a, b = 4, c = 'blah-blah', *args, **kwargs):
pass

test(1)
#test(1, 3)
#test(1, d = 5)
test(1, 2, 3, 4, 5, d = 6, g = 12.9)

有点效果，但有一些缺陷：

打电话

test(1, 2, 3, 4, 5, d = 6, g = 12.9)

资讯科技印刷

test ( a = 1, b = 2, c = 3, d = 6, g = 12.9 )。

预期结果是

test ( a = 1, b = 2, c = 3, args = [4, 5], kwargs = {'d': 6, 'g': 12.9} )

我被困在这里了。你能帮我找到正确的解决办法吗？

相关讨论

对不起，有点乱。我修改了http://wiki.python.org/moin/pythondecoratorlibrary easy dump的函数参数中的一些代码。

1
2
3
4
5
6
7
8
9
10
11
12
13

def dump_args(func):
"This decorator dumps out the arguments passed to a function before calling it"
argnames = func.func_code.co_varnames[:func.func_code.co_argcount]
fname = func.func_name
def echo_func(*args,**kwargs):
print fname,"(", ', '.join(
'%s=%r' % entry
for entry in zip(argnames,args[:len(argnames)])+[("args",list(args[len(argnames):]))]+[("kwargs",kwargs)]) +")"
return echo_func

@dump_args
def test(a, b = 4, c = 'blah-blah', *args, **kwargs):
pass

试验(1，2，3，4，5，d=6，g=12.9)

输出：

测试(a=1，b=2，c=3，args=[4，5]，kwargs='d'：6，'g'：12.9)

相关讨论

这是python 3.6的更新版本+

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

import inspect

def dump_args(func):
"""Decorator to print function call details - parameters names and effective values.
"""
def wrapper(*args, **kwargs):
func_args = inspect.signature(func).bind(*args, **kwargs).arguments
func_args_str = ', '.join('{} = {!r}'.format(*item) for item in func_args.items())
print(f'{func.__module__}.{func.__qualname__} ( {func_args_str} )')
return func(*args, **kwargs)
return wrapper

@dump_args
def test(a, b=4, c='blah-blah', *args, **kwargs):
pass

test(1)
test(1, 3)
test(1, d=5)
test(1, 2, 3, 4, 5, d=6, g=12.9)

旧版本

使用默认值的工作版本：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

def dumpArgs(func):
'''Decorator to print function call details - parameters names and effective values'''
def wrapper(*func_args, **func_kwargs):
arg_names = func.func_code.co_varnames[:func.func_code.co_argcount]
args = func_args[:len(arg_names)]
defaults = func.func_defaults or ()
args = args + defaults[len(defaults) - (func.func_code.co_argcount - len(args)):]
params = zip(arg_names, args)
args = func_args[len(arg_names):]
if args: params.append(('args', args))
if func_kwargs: params.append(('kwargs', func_kwargs))
print func.func_name + ' (' + ', '.join('%s = %r' % p for p in params) + ' )'
return func(*func_args, **func_kwargs)
return wrapper

@dumpArgs
def test(a, b = 4, c = 'blah-blah', *args, **kwargs):
pass

test(1)
test(1, 3)
test(1, d = 5)
test(1, 2, 3, 4, 5, d = 6, g = 12.9)

结果：

1
2
3
4

>>> test ( a = 1, b = 4, c = 'blah-blah' )
test ( a = 1, b = 3, c = 'blah-blah' )
test ( a = 1, b = 4, c = 'blah-blah', kwargs = {'d': 5} )
test ( a = 1, b = 2, c = 3, args = (4, 5), kwargs = {'d': 6, 'g': 12.9} )

相关讨论

下面是我在python 3中解决它的方法，基于aliteralmind的答案，如果我可以这么说的话，可以更清晰地放置(pep8)。清理工作的大部分灵感来自罗伯特·金(Robert King)目前接受的答案。

代码：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

import logging

def log_function_entry_and_exit(decorated_function):
"""
Function decorator logging entry + exit and parameters of functions.

Entry and exit as logging.info, parameters as logging.DEBUG.
"""
from functools import wraps

@wraps(decorated_function)
def wrapper(*dec_fn_args, **dec_fn_kwargs):
# Log function entry
func_name = decorated_function.__name__
log = logging.getLogger(func_name)
log.info('Entering {}()...'.format(func_name))

# get function params (args and kwargs)
arg_names = decorated_function.__code__.co_varnames
params = dict(
args=dict(zip(arg_names, dec_fn_args)),
kwargs=dec_fn_kwargs)

log.debug(
"\t" + ', '.join([
'{}={}'.format(str(k), repr(v)) for k, v in params.items()]))
# Execute wrapped (decorated) function:
out = decorated_function(*dec_fn_args, **dec_fn_kwargs)
log.info('Done running {}()!'.format(func_name))

return out
return wrapper

@log_function_entry_and_exit
def func1(a, b, c):
print("
\ty'elo2!
")
@log_function_entry_and_exit
def a(x, y, z):
print("
\ty'elo!
")

LOG_FORMAT = '[{}] !%(levelname)s! %(funcName)s: %(message)s'.format(
_get_current_time_string(just_time_string=True))
logging.basicConfig(format=LOG_FORMAT, level=logging.DEBUG)

a(x=1, y="b", z={'c': 2})
func1(2, b="y", c={'z': 4})
func1(2,"y", {'z': 4})

输出：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

In [6]: a(x=1, y="b", z={'c': 2})
...: func1(2, b="y", c={'z': 4})
...: func1(2,"y", {'z': 4})
...:
[2016.09.22 - 17:31:48] !INFO! wrapper: Entering a()...
[2016.09.22 - 17:31:48] !DEBUG! wrapper: kwargs={'x': 1, 'z': {'c': 2}, 'y': 'b'}, args={}

y'elo!

[2016.09.22 - 17:31:48] !INFO! wrapper: Done running a()!
[2016.09.22 - 17:31:48] !INFO! wrapper: Entering func1()...
[2016.09.22 - 17:31:48] !DEBUG! wrapper: kwargs={'c': {'z': 4}, 'b': 'y'}, args={'a': 2}

y'elo2!

[2016.09.22 - 17:31:48] !INFO! wrapper: Done running func1()!
[2016.09.22 - 17:31:48] !INFO! wrapper: Entering func1()...
[2016.09.22 - 17:31:48] !DEBUG! wrapper: kwargs={}, args={'c': {'z': 4}, 'a': 2, 'b': 'y'}

y'elo2!

[2016.09.22 - 17:31:48] !INFO! wrapper: Done running func1()!

注意：输出中的wrapper字符串表示使logging.X()消息调用的任何对象的函数名。

使用实例：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

In [1]: from meh import execute_os_command

In [2]: from meh import LOG_FORMAT

In [3]: import logging

In [4]: logging.basicConfig(format=LOG_FORMAT, level=logging.INFO)
...:
...: logging.info("Entered script...
")
...:
...: result = execute_os_command(cmd=["echo","trololol"])
...: print("
{}
".format(result))
...: execute_os_command(cmd=["echo","trololol"], dry_run=True)
...:
...: logging.info("Exiting script...
")
...:
[2016.09.22 - 17:42:19] !INFO! <module>: Entered script...

[2016.09.22 - 17:42:19] !INFO! wrapper: Entering execute_os_command()...
[2016.09.22 - 17:42:19] !INFO! execute_os_command: Executing:
[2016.09.22 - 17:42:19] !INFO! execute_os_command: echo trololol
[2016.09.22 - 17:42:19] !INFO! execute_os_command: Waiting for above command to finish execution...
[2016.09.22 - 17:42:19] !INFO! wrapper: Done running execute_os_command()!

{'stderr': '', 'stdout': 'trololol
', 'command': ['echo', 'trololol'], 'returncode': 0, 'stdin': None, 'timedout': False}

[2016.09.22 - 17:42:19] !INFO! wrapper: Entering execute_os_command()...
[2016.09.22 - 17:42:19] !INFO! execute_os_command: Would have executed:
[2016.09.22 - 17:42:19] !INFO! execute_os_command: echo trololol
[2016.09.22 - 17:42:19] !INFO! execute_os_command: Exiting execute_os_command()...
[2016.09.22 - 17:42:19] !INFO! wrapper: Done running execute_os_command()!
[2016.09.22 - 17:42:19] !INFO! <module>: Exiting script...

In [5]:

当我得到被称为"时间和能量"的神奇资源时，我很想和LOG_FORMAT一起玩，并弄清楚如何用say filename和linenumber of function invocation=替换wrapper子字符串。

@Warvariuc的答案，升级到python 3：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

def dumpArgs(func):
'''Decorator to print function call details - parameters names and effective values'''
def wrapper(*func_args, **func_kwargs):
arg_names = func.__code__.co_varnames[:func.__code__.co_argcount]
args = func_args[:len(arg_names)]
defaults = func.__defaults__ or ()
args = args + defaults[len(defaults) - (func.__code__.co_argcount - len(args)):]
params = list(zip(arg_names, args))
args = func_args[len(arg_names):]
if args: params.append(('args', args))
if func_kwargs: params.append(('kwargs', func_kwargs))
print(func.__name__ + ' (' + ', '.join('%s = %r' % p for p in params) + ' )')
return func(*func_args, **func_kwargs)
return wrapper

@dumpArgs
def test(a, b = 4, c = 'blah-blah', *args, **kwargs):
pass

test(1)
test(1, 3)
test(1, d = 5)
test(1, 2, 3, 4, 5, d = 6, g = 12.9)

相关讨论

这是一个有点老的帖子，但想增加我的一点。Warvariuc给出的解决方案并不适用于所有情况。如果一个方法具有默认值，并且我们在调用时发送命名参数，那么它不会给出正确的输出。例如，我们得到两个b值。

1 2	test(1, b = 5) test (a = 1, b = 4, c = 'blah-blah', kwargs = {'b': 5} )

添加我修改的代码。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

def print_args(func):
"""
Function to print all args of decorated function
"""
def wrapper(*func_args, **func_kwargs):
arg_names = func.func_code.co_varnames[:func.func_code.co_argcount]
args = func_args[:len(arg_names)]
defaults = func.func_defaults or ()
args = args + defaults[len(defaults) - (func.func_code.co_argcount - len(args)):]
params = zip(arg_names, args)
new_arg_list = [list(i) for i in params]
for key in func_kwargs:
for param in new_arg_list:
if key == param[0]:
param[1] = func_kwargs[key]
new_arg_list = [tuple(i) for i in new_arg_list]
print func.func_name + ' (' + ', '.join('%s = %r' % p for p in new_arg_list) + ' )'
return func(*func_args, **func_kwargs)
return wrapper

@print_args
def test_params(a=7,b=5):
pass

test_params(a=3)

产量

1	test_params (a = 3, b = 5 )