Dynamically catch exceptions in callback function

October 15, 2022

I’m writing a basic logging utility, and I want it to use a callback function, and then check for a list of exceptions that might have occurred.

I think the code will explain for itself.
I know the following example is not valid code, it is included for clarification.

    def Except(self, func, exceptions, *args, **kwargs):
        """Used for logging exceptions"""
        try:
            func(*args, **kwargs)
        for exception in exceptions: # Obviously this doesn't work.
            except exception as e:
                self.log(f"{e}", "error", 4)

However, I am surprised unpacking doesn’t work.

    def Except(self, func, exceptions, *args, **kwargs):
        """Used for logging exceptions"""
        try:
            func(*args, **kwargs)
        except (*exceptions) as e:
            self.log(f"{e}", "error", 4)

Is there any way to dynamically catch exceptions with a callback function like this? I can’t seem to find anything in the docs about it.

>Solution :

You can create a custom Except class like this,

def Except(func, exceptions, *args, **kwargs):
    try:
        func(*args, **kwargs)
    except exceptions as e:
        print(f"{e}", "error")

def foo():
    l = [1]
    return l[1]
    
# Exception as tuple
exceptions = (TypeError, KeyError, IndexError)

Except(foo, exceptions)

Outputs: