如何在python中用相同的包装器包装许多函数

Question

I am new in Python and I did not find a clear method yet.

I have several functions (possibly hundreds) that I want to wrap in the same code over and over.

try:
    OneOfTheOneHundredFunctions()

except MY_ERROR as error:
    print('Error: I caught an error')

Do I have to specify the wrapper for each of the OneOfTheOneHundredFunctions() ? In C++, I would do that with a macro , is there something similar in python?

Answer 1

You can reference functions by their name, so you can collect them in some iterable

for index, fn in enumerate((  
    function1,
    function2,
    function3,
)):
    try:
        fn()
    except Exception as ex:
        print(f"ERROR: function {index} raised {repr(ex)}")

enumerate is just convenient here to get the index of the function in a tuple, but you can put the names into any iterable, like a dict and also name the functions (with some comment?)

functions_dict = {"check A": fn1, "check B": fn2, ...}
for comment, function in functions_dict.items():
    ...

Answer 2

You could essentially create a function with the wrapper, and pass in a pointer to the other functions you want. Inside the wrapper you would call the function that's pointed to.

def catch_error(my_function):
    try:
        my_function()
    except MY_ERROR as error:
        print('Error: I caught an error')

list_of_functions = [OneOfTheHundredFunctions, TwoOfTheHundredFunctions, ...]
for function in list_of_functions:
    catch_error(function)


# Calling functions out of order
catch_error(TwoOfTheHundredFunctions)
# Some more logic
catch_error(OneOfTheHundredFunctions)

Answer 3

Functions and Exceptions are first-class members in Python, so you can simply pass them into another function that does the try/except block:

def try_to_run(function, error_to_catch, *args, **kwargs):
    try:
        return function(*args, **kwargs)
    except error_to_catch:
        print('Error: I caught an error')

def OneOfTheOneHundredFunctions():
    pass

MY_ERROR = ValueError

result = try_to_run(
    function=OneOfTheOneHundredFunctions, 
    error_to_catch=MY_ERROR,
)

Note that any additional arguments/keyword arguments passed to try_to_run are passed in to the actual function you're wrapping around the try/except (that's what the *args and **kwargs are for).

Answer 4

If you have functions in separate file, or I think you may separate it. Then you can use this to get list of function from that module/file:
How to list all functions in a Python module? another answer same but I think some description.

 from inspect import getmembers, isfunction from my_project import my_module list_of_functions = getmembers(my_module, isfunction)

And now you can follow OPs ideas.

Like @nanotek said :

def catch_error(my_function):
    try:
        my_function()
    except MY_ERROR as error:
        print('Error: I caught an error')

for function in list_of_functions:
    catch_error(function)