Take a deep breath and prepare for some serious Show & Tell; it's time to learn about xonsh extensions!
Xonsh comes with some default set of extensions. These can be viewed :py:mod:`here <xontrib>`.
Also checkout the list of Awesome Contributions from the community.
Xontributions, or xontribs
, are a set of tools and conventions for
extending the functionality of xonsh beyond what is provided by default. This
allows 3rd party developers and users to improve their xonsh experience without
having to go through the xonsh development and release cycle.
Many tools and libraries have extension capabilities. Here are some that we took inspiration from for xonsh:
- Sphinx: Extensions are just Python modules, bundles some extensions with the main package, interface is a list of string names.
- IPython: Extensions are just Python modules with some special functions to load/unload.
- Oh My Zsh: Centralized registry, autoloading, and for a shell.
- ESLint: Ability to use language package manager to install/remove extensions.
Xontribs are modules with some special functions written
in either xonsh (*.xsh
) or Python (*.py
).
Here is a template:
from xonsh.built_ins import XonshSession
def _load_xontrib_(xsh: XonshSession, **kwargs) -> dict:
"""
this function will be called when loading/reloading the xontrib.
Args:
xsh: the current xonsh session instance, serves as the interface to manipulate the session.
This allows you to register new aliases, history backends, event listeners ...
**kwargs: it is empty as of now. Kept for future proofing.
Returns:
dict: this will get loaded into the current execution context
"""
def _unload_xontrib_(xsh: XonshSession, **kwargs) -> dict:
"""If you want your extension to be unloadable, put that logic here"""
This _load_xontrib_() function is called after your extension is imported, and the currently active :py:class:`xonsh.built_ins.XonshSession` instance is passed as the argument.
Note
Xontribs without _load_xontrib_
are still supported.
But when such xontrib is loaded, variables listed
in __all__
are placed in the current
execution context if defined.
Normally, these are stored and found in an
implicit namespace package
called xontrib
. However, xontribs may be placed in any package or directory
that is on the $PYTHONPATH
.
If a module is in the xontrib
namespace package, it can be referred to just
by its module name. If a module is in any other package, then it must be
referred to by its full package path, separated by .
like you would in an
import statement. Of course, a module in xontrib
may be referred to
with the full xontrib.myext
. But just calling it myext
is a lot shorter
and one of the main advantages of placing an extension in the xontrib
namespace package.
Here is a sample file system layout and what the xontrib names would be:
|- xontrib/ |- javert.xsh # "javert", because in xontrib |- your.py # "your", |- eyes/ |- __init__.py |- scream.xsh # "eyes.scream", because eyes is in xontrib |- mypkg/ |- __init__.py # a regular package with an init file |- other.py # not a xontrib |- show.py # "mypkg.show", full module name |- tell.xsh # "mypkg.tell", full module name |- subpkg/ |- __init__.py |- done.py # "mypkg.subpkg.done", full module name
You can also use the xontrib template to easily create the layout for your xontrib package.
Xontribs may be loaded in a few different ways: from the config file
(e.g. ~/.config/xonsh/rc.xsh
), dynamically at runtime with
the xontrib
command, or its Python API.
Extensions are loaded via the xontrib load
command.
This command may be run from anywhere in a xonshrc file or at any point
after xonsh has started up.
xontrib load myext mpl mypkg.show
The same can be done in Python as well
from xonsh.xontribs import xontribs_load
xontribs_load(['myext', 'mpl', 'mypkg.show'])
A xontrib can be unloaded from the current session using xontrib unload
xontrib unload myext mpl mypkg.show
Xontribs can use setuptools entrypoints to mark themselves available for autoloading using the below format.
[options.entry_points]
xonsh.xontribs =
xontrib_name = path.to.the.module
Here the module should contain _load_xontrib_
function as described above.
Note
Please make sure that importing the xontrib module and calling _load_xontrib_
is fast enough.
Otherwise it will affect the shell's startup time.
Any other imports or heavy computations should be done in lazy manner whenever possible.
In addition to loading extensions, the xontrib
command also allows you to
list the installed xontribs. This command will report if they are loaded
in the current session. To display this
information, pass the list
action to the xontrib
command:
>>> xontrib list
mpl not-loaded
myext not-loaded
For programmatic access, you may also have this command print a JSON formatted string:
>>> xontrib list --json mpl
{"mpl": {"loaded": false, "installed": true}}
Writing a xontrib is as easy as writing a xonsh or Python file and sticking
it in a directory named xontrib/
. However, please do not place an
__init__.py
in the xontrib/
directory. It is an
implicit namespace package and should not have one. See
PEP 420 for more details.
Warning
Do not place an __init__.py
in the xontrib/
directory!
If you plan on using *.xsh
files in you xontrib, then you'll
have to add some hooks to distutils, setuptools, pip, etc. to install these
files. Try adding entries like the following entries to your setup()
call
in your setup.py
:
try:
from setuptools import setup
except ImportError:
from distutils.core import setup
setup(...,
packages=[..., 'xontrib'],
package_dir={..., 'xontrib': 'xontrib'},
package_data={..., 'xontrib': ['*.xsh']},
...)
Something similar can be done for any non-xontrib package or sub-package
that needs to distribute *.xsh
files.
We request that you register your xontrib with us. We think that will make your contribution more discoverable.
To register a xontrib, create a PullRequest
at
Awesome-xontribs
repository. Also, if you use Github to host your code,
please add xonsh and xontrib
to the topics.
All of this let's users know that your xontrib is out there, ready to be used. Of course, you're under no obligation to register your xontrib. Users will still be able to load your xontrib, as long as they have it installed.
Go forth!