Packages may provide commands to be run at the console (console scripts),
such as the
pip command. These commands are defined for a package
as a specific kind of entry point in the
First consider an example without entry points. Imagine a package defined thus:
timmins/ timmins/__init__.py timmins/__main__.py setup.cfg # or setup.py #other necessary files
def hello_world(): print("Hello world")
__main__.py providing a hook:
from . import hello_world if __name__ == '__main__': hello_world()
After installing the package, the function may be invoked through the runpy module:
python -m timmins
Adding a console script entry point allows the package to define a
user-friendly name for installers of the package to execute. Installers
like pip will create wrapper scripts to execute a function. In the
above example, to create a command
hello-world that invokes
timmins.hello_world, add a console script entry point to
[options.entry_points] console_scripts = hello-world = timmins:hello_world
After installing the package, a user may invoke that function by simply calling
hello-world on the command line.
The syntax for entry points is specified as follows:
<name> = [<package>.[<subpackage>.]]<module>[:<object>.<object>]
name is the name for the script you want to create, the left hand
: is the module that contains your function and the right hand
side is the object you want to invoke (e.g. a function).
In addition to
console_scripts, Setuptools supports
will launch a GUI application without running in a terminal window.
Console scripts are one use of the more general concept of entry points. Entry points more generally allow a packager to advertise behavior for discovery by other libraries and applications. This feature enables “plug-in”-like functionality, where one library solicits entry points and any number of other libraries provide those entry points.
A good example of this plug-in behavior can be seen in
where pytest is a test framework that allows other libraries to extend
or modify its functionality through the
pytest11 entry point.
The console scripts work similarly, where libraries advertise their commands
and tools like
pip create wrapper scripts that invoke those commands.
For example, to find the console script entry points from the example above:
>>> from importlib import metadata >>> eps = metadata.entry_points()['console_scripts']
eps is now a list of
EntryPoint objects, one of which corresponds
hello-world = timmins:hello_world defined above. Each
value. It also supplies a
method to import and load that entry point (module or object).
[options.entry_points] my.plugins = hello-world = timmins:hello_world
Then, a different project wishing to load ‘my.plugins’ plugins could run the following routine to load (and invoke) such plugins:
>>> from importlib import metadata >>> eps = metadata.entry_points()['my.plugins'] >>> for ep in eps: ... plugin = ep.load() ... plugin()
The project soliciting the entry points needs not to have any dependency or prior knowledge about the libraries implementing the entry points, and downstream users are able to compose functionality by pulling together libraries implementing the entry points.
Some entry points may require additional dependencies to properly function.
For such an entry point, declare in square brakets any number of dependency
extras following the entry point definition. Such entry points will only
be viable if their extras were declared and installed. See the
guide on dependencies management for
more information on defining extra requirements. Consider from the
[options.entry_points] console_scripts = hello-world = timmins:hello_world [pretty-printer]
In this case, the
hello-world script is only viable if the
extra is indicated, and so a plugin host might exclude that entry point
(i.e. not install a console script) if the relevant extra dependencies are not