python - A decorator that profiles a method call and logs the profiling result

Question

I want to create a decorator that profiles a method and logs the result. How can this be done?

Answer 1

If you want proper profiling instead of timing, you can use an undocumented feature of cProfile (from this question):

import cProfile

def profileit(func):
    def wrapper(*args, **kwargs):
        datafn = func.__name__ + ".profile" # Name the data file sensibly
        prof = cProfile.Profile()
        retval = prof.runcall(func, *args, **kwargs)
        prof.dump_stats(datafn)
        return retval

    return wrapper

@profileit
def function_you_want_to_profile(...)
    ...

If you want more control over the file name then you will need another layer of indirection:

import cProfile

def profileit(name):
    def inner(func):
        def wrapper(*args, **kwargs):
            prof = cProfile.Profile()
            retval = prof.runcall(func, *args, **kwargs)
            # Note use of name from outer scope
            prof.dump_stats(name)
            return retval
        return wrapper
    return inner

@profileit("profile_for_func1_001")
def func1(...)
    ...

It looks complicated, but if you follow it step by step (and note the difference in invoking the profiler) it should become clear.