Use Line_profiler Without Magic

I found this excellent blog post, from Lothiraldan, on how to unmagickify line_profiler.

Adding a @profile decorator is all that’s needed, if you invoke the python code through kernprof. kernprof injects the necessary dependencies.

But I’ve always felt it was icky because it severely restricts the supported and documented use cases. How do I profile flask? Or pudb?

As it turns out, it’s just requires a little bit of boilerplate to replicate kernprof.

import line_profiler
profile = line_profiler.LineProfiler()

import atexit
atexit.register(profile.print_stats)

That’s literally all I use kernprof for:

• it magically imports @profile decorator but I can just mundanely import a decorator.
• it registers a “finally” to print the profiling output. Not rocket science.

Voila! Now it’s the long game of waiting for another situation to arise, for which this is the exact magic bullet. Insert reference to XKCD.