easyprofile — Easy context-based profiling for Python
The easyprofile package provides facilities for setting Python's
sys.setprofile() locally within a context, together with a number of helpers
to automate profiling and logging.
Installation
Install as usual with pip:
pip install easyprofileUsage
Replacing sys.setprofile() locally
If you wish to install a profile function that you would otherwise pass to
sys.setprofile() within a local context, use the easyprofile.profile
context manager:
>>> import easyprofile
>>>
>>> # profile function of the sys.setprofile() form
>>> def myfunc(frame, event, arg):
... print('profile:', event)
...
>>> # a test function to be profiled
>>> def profile_this(n):
... # this inner function call will not show in the profile
... return sum(range(n))
...
>>> # replace the profile function locally
>>> with easyprofile.profile(myfunc):
... # only this call will be profiled
... profile_this(100_000_000)
...
profile: call
profile: return
4999999950000000Ignoring calls
If you wish to ignore some calls locally, you can use the easyprofile.ignore
context manager:
>>> with easyprofile.profile(myfunc):
... # this call will be profiled
... profile_this(100_000_000)
...
... with easyprofile.ignore:
... # this call will be ignored
... profile_this(100)
...
profile: call
profile: return
4999999950000000
4950The context manager works by temporarily setting sys.setprofile() to None,
and hence works with any profiler.
Note that easyprofile.ignore is not a callable!
Marking functions as ignored
Functions can be marked as always ignored using the @easyprofile.ignored
decorator:
>>> # this function is ignored by easyprofile
>>> @easyprofile.ignored
... def ignored_func():
... return 42
...
>>> with easyprofile.profile(myfunc):
... ignored_func()
...
42Note that unlike the easyprofile.ignore context manager, the decorator only
works with easyprofile.
Class-based profilers
To facilitate the creation of custom profilers, the easyprofile.BaseProfile
class provides a method-based interface to handling events. A method
with a name _<event> (i.e. underscore -- event name) is called whenever the
event <event> is encountered, with a signature of frame, arg.
>>> class MyProfile(easyprofile.BaseProfile):
... def __init__(self, arg, *, kwarg):
... print(f'MyProfile: init, {arg=}, {kwarg=}')
...
... def _attach(self, frame, arg):
... print('MyProfile: attached')
...
... def _detach(self, frame, arg):
... print('MyProfile: detached')
...
... def _call(self, frame, arg):
... print('MyProfile: function called')
...
... def _return(self, frame, arg):
... print('MyProfile: function returned')
...
... # profile C extension calls using the same methods
... _c_call = _call
... _c_return = _return
...The class-based profilers are easily invoked through their profile() class
method, which forwards its arguments to the constructor:
>>> # use the MyProfile class for local profiling
>>> with MyProfile.profile('hello', kwarg='world'):
... profile_this(100_000_000)
...
MyProfile: init, arg='hello', kwarg='world'
MyProfile: function called
MyProfile: function returned
4999999950000000
