cProfile command-line should accept "-m module_name" as an alternative to script path

[pitrou]

BPO	21862
Nosy	@birkenfeld, @amauryfa, @ncoghlan, @pitrou, @berkerpeksag, @CuriousLearner
PRs	bpo-21862: Add -m option to cProfile for profiling modules #4297
Files	cProfile-add-new-option-module.patch: patch 21862.patch cProfile_module_option.patch: patch cProfile_module_option_2.patch: patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2017-11-08.10:51:30.237>
created_at = <Date 2014-06-24.20:06:54.143>
labels = ['3.7', 'easy', 'type-feature', 'library']
title = 'cProfile command-line should accept "-m module_name" as an alternative to script path'
updated_at = <Date 2017-11-08.11:21:16.579>
user = 'https://github.com/pitrou'

bugs.python.org fields:

activity = <Date 2017-11-08.11:21:16.579>
actor = 'CuriousLearner'
assignee = 'none'
closed = True
closed_date = <Date 2017-11-08.10:51:30.237>
closer = 'pitrou'
components = ['Library (Lib)']
creation = <Date 2014-06-24.20:06:54.143>
creator = 'pitrou'
dependencies = []
files = ['35775', '36094', '37749', '37885']
hgrepos = []
issue_num = 21862
keywords = ['patch', 'easy']
message_count = 20.0
messages = ['221488', '221502', '221546', '224008', '232932', '234195', '234560', '234614', '234863', '238195', '305666', '305667', '305668', '305714', '305720', '305741', '305742', '305819', '305820', '305822']
nosy_count = 9.0
nosy_names = ['georg.brandl', 'amaury.forgeotdarc', 'ncoghlan', 'pitrou', 'gennad', 'berker.peksag', 'rock', 'oquanox', 'CuriousLearner']
pr_nums = ['4297']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue21862'
versions = ['Python 3.7']

[pitrou]

As the title says. You should be able to type:

$ python -m cProfile -m my.module.name

to profile execution of my.module.name.

[Rock]

I tweaked the Lib/cProfile.py a little bit to get the feature done, please review the patch attached.

[pitrou]

That's not how -m should work. It should use the runpy facilities (see the runpy module). Otherwise it probably won't work properly with qualified module names ("-m pkg.subpkg.mod").

[gennad]

I added runpy import mechanism

[amauryfa]

The patch does not seem to allow parameters after the -m option.
I'm sure this restriction can be lifted.

[oquanox]

Now allows parameters after the -m option.

[amauryfa]

This change will cause the module to be imported twice:
progname = runpy.run_module(args[0])['__file__']
... and then the runctx() call.

What about something like:
code = "runpy.run_module(modname, run_name='__main__')"
globs = { 'runpy': runpy, 'modname': args[0] }

[ncoghlan]

I haven't looked into the details of how cProfile handles command line arguments, but potentially relevant is issue bpo-19982, which proposes adding a "target" parameter that lets runpy run in the context of an existing module object, rather than always creating its own.

However, if this can be implemented without that, go ahead - it can always be refactored later.

[oquanox]

Updated the patch and added docs and tests.

[oquanox]

Could someone please review the patch. Thanks.

[CuriousLearner]

Hey, seems like this bug is not updated for a while. Can I work on this?