How to use Profiler with Click CLI in Python

Question

I have code base for which I am using Click package to manage the CLI. Is there a way to profile the code for optimization using cProfiler?

import cProfile
import click
import io

def profile(fnc):

"""A decorator that uses cProfile to profile a function"""

def inner(*args, **kwargs):

    pr = cProfile.Profile()
    pr.enable()
    retval = fnc(*args, **kwargs)
    pr.disable()
    s = io.StringIO()
    sortby = 'cumulative'
    ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
    ps.print_stats()
    print(s.getvalue())
    return retval

return inner

@click.group()
def cli1():
    pass

@profile
@cli1.command()
@click.option('--zoom', '-z', type=int, default=1)
def fixed(zoom):
   # Function goes here

cli = click.CommandCollection(sources=[cli1, default])

if __name__ == '__main__':
    cli()

I need to profile the fixed function in the Python code.

What is the point of measuring the performance of a command line processor? — Stephen Rauch
– Stephen Rauch ♦, Commented Apr 28, 2019 at 1:44
I don't want to measure the performance of CLI processor. I wish to check the performance of the individual functions within. — naseefo
– naseefo, Commented Apr 29, 2019 at 6:29

erb · Accepted Answer · 2020-03-01 12:08:01Z

10

I needed to do the same, and with some help from your code I came up with this:

import click

@click.group()
@click.option("--profile", is_flag=True)
def main(profile: bool) -> None:
    if profile:
        import cProfile
        import pstats
        import io
        import atexit

        print("Profiling...")
        pr = cProfile.Profile()
        pr.enable()

        def exit():
            pr.disable()
            print("Profiling completed")
            s = io.StringIO()
            pstats.Stats(pr, stream=s).sort_stats("cumulative").print_stats()
            print(s.getvalue())

        atexit.register(exit)

My main function is your cli1 function.

Then you can simply pass the --profile flag to your CLI and it'll profile whatever subcommand of the group you want.

answered Mar 1, 2020 at 12:08

erb

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1 Comment

Newtopian Over a year ago

hooo what an elegant way to integrate this with click ! thanks

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