问题
I want to make a function that being a decorator to another function will print that function call details - parameters names and effective values. My current implementation is this.
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)
Kinda works, but with some bugs:
For call
test(1, 2, 3, 4, 5, d = 6, g = 12.9)
it prints
test ( a = 1, b = 2, c = 3, d = 6, g = 12.9 )
.
The expected result is
test ( a = 1, b = 2, c = 3, args = [4, 5], kwargs = {'d': 6, 'g': 12.9} )
I got stuck here. Can you help me to find the right solution?
回答1:
Sorry its a bit messy. I modified some code from http://wiki.python.org/moin/PythonDecoratorLibrary#Easy_Dump_of_Function_Arguments
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
test(1, 2, 3, 4, 5, d = 6, g = 12.9)
output:
test ( a=1, b=2, c=3, args=[4, 5], kwargs={'d': 6, 'g': 12.9})
回答2:
Here is the updated version for Python 3.6+
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)
Old version
Working version with default values:
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)
Result:
>>> 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} )
回答3:
Here's how I solved it in Python 3, based on aliteralmind's answer, put more cleanly (PEP8) if I may say so. Majority of the inspiration for the cleanup came from the (currently) accepted answer by Robert King.
Code:
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("\n\ty'elo2!\n")
@log_function_entry_and_exit
def a(x, y, z):
print("\n\ty'elo!\n")
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})
Output:
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()!
Note: The wrapper
string in the output represents the function name of whatever makes the logging.X()
message call.
Example in use:
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...\n")
...:
...: result = execute_os_command(cmd=["echo", "trololol"])
...: print("\n{}\n".format(result))
...: execute_os_command(cmd=["echo", "trololol"], dry_run=True)
...:
...: logging.info("Exiting script...\n")
...:
[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\n', '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]:
When I get the magical resources known as "time and energy", I'm interested in playing around with LOG_FORMAT
, and figure out how I can replace the wrapper
substring with say filename and linenumber of function invocation =)
回答4:
@warvariuc's answer, upgraded to Python 3:
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)
回答5:
Its a bit old post but wanted to add my bit. Solution given by warvariuc does not work in all cases. If a method have default values as well as we send named arguments while calling, it does not give proper output. e.g. we get two values of b.
test(1, b = 5)
test (a = 1, b = 4, c = 'blah-blah', kwargs = {'b': 5} )
Adding my modified code.
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)
Output
test_params (a = 3, b = 5 )
来源:https://stackoverflow.com/questions/6200270/decorator-to-print-function-call-details-parameters-names-and-effective-values