Counting the number of function calls

Question

So, I have a code snippet to count the number of function calls, and while browsing for potential optimal solutions, I came across a similar question posted here a few years ago:

is there a way to track the number of times a function is called?

One of the solutions listed in the thread above matched mine, but there was a subtle difference. When I posted my solution and asked about the potential pitfalls in my code, my comment was deleted even though mine was a solution to the question. So, I am hoping this one isn't closed as a duplicate, because frankly I don't know where to turn to.

Here was my solution:

def counter(func):
    counter.count=0
    def wrap(*args,**kwargs):
        counter.count += 1
        print "Number of times {} has been called so far 
            {}".format(func.__name__,counter.count)
        func(*args,**kwargs)
    return wrap

@counter
def temp(name):
    print "Calling {}".format(name)

My counter is defined as an attribute to the decorator 'counter', instead of the wrapper function 'wrap'. The code works as currently defined. But, is there a scenario where it may fail? Am I overlooking something here?

Answer 1

If you use this decorator on two separate functions, they'll share the same call count. That's not what you want. Also, every time this decorator is applied to a new function, it will reset the shared call count.

Aside from that, you've also forgotten to pass through the return value of func in wrap , and you can't stick an unescaped line break in the middle of a non-triple-quoted string literal like that.

Answer 2

With slight modification to your code you can make your counter decorator independent:

def counter(func, counter_dict={}):
    counter_dict[func]=0
    def wrap(*args,**kwargs):
        counter_dict[func] += 1
        print("Number of times {} has been called so far {}".format(func.__name__, counter_dict[func]))
        return func(*args,**kwargs)
    return wrap

@counter
def temp1(name):
    print("Calling temp1 {}".format(name))

@counter
def temp2(name):
    print("Calling temp2 {}".format(name))


temp1('1')
temp1('2')
temp2('3')

Prints:

Number of times temp1 has been called so far 1
Calling temp1 1
Number of times temp1 has been called so far 2
Calling temp1 2
Number of times temp2 has been called so far 1
Calling temp2 3