21 KiB
Python layer
- Description
- Install
- Backends
- Additional tools
- Configuration
- Management of Python versions and virtual environments
- Key bindings
Description
This layer adds support for the Python language.
Features:
-
Support for the following backends:
- anaconda (default),
- Language Server Protocol (experimental),
- Auto-completion
- Code Navigation
- Documentation Lookup using anaconda-mode and pylookup
- Test Runners using nose.el or pytest
- Virtual Environment using pyvenv and pyenv
- semantic mode is enabled
- PEP8 compliant formatting via YAPF or black
- PEP8 checks with flake8 or pylint
- Suppression of unused import with autoflake
- Use the
%
key to jump between blocks with evil-matchit - Sort imports with isort
- Fix a missing import statement with importmagic
- Pip package manager with pippel
Install
Layer
To use this configuration layer, add it to your ~/.spacemacs
. You will need to
add python
to the existing dotspacemacs-configuration-layers
list in this
file.
Choosing a backend
To choose a default backend set the layer variable python-backend
:
(python :variables python-backend 'anaconda)
Backend can be chosen on a per project basis using directory local variables
(files named .dir-locals.el
at the root of a project), an example to use the
lsp
backend:
;;; Directory Local Variables
;;; For more information see (info "(emacs) Directory Variables")
((python-mode (python-backend . lsp)))
Note: you can easily add a directory local variable with SPC f v d
.
Backends
Anaconda
anaconda-mode
tries to install the dependencies itself but sometimes
it does not work and you may encounter the following message when
opening a python buffer:
Blocking call to accept-process-output with quit inhibited!!
To fix this, install the anaconda-mode
anaconda-deps by hand:
pip install --upgrade "jedi>=0.9.0" "json-rpc>=1.8.1" "service_factory>=0.1.5"
If you encounter problems with Jedi 1.0 consider downgrading to 0.9.0. See this issue for details.
Source: https://github.com/proofit404/anaconda-mode#issues
If you are facing errors such as “Unable to run anaconda-mode server”, try
setting your PYTHONPATH
as explained at
https://github.com/proofit404/anaconda-mode#pythonpath
Language Server Protocol
You just have to install python language server package:
pip install python-language-server
Additionally you can install the following other packages:
# for import sorting
pip install pyls-isort
# for mypy checking (python 3.4+ is needed)
pip install pyls-mypy
If you’ve installed the language server and related packages as development
dependencies in a pipenv environment, you’ll want to set the python-pipenv-activate
config variable to t
. This activates your pipenv before enabling the
lsp backend.
Additional tools
Syntax checking
Syntax checking uses flake8
package:
pip install flake8
Test runner
Both nose
and pytest
are supported. By default nose
is used.
To choose your test runner set the layer variable python-test-runner
to
either nose
or pytest
.
(setq-default dotspacemacs-configuration-layers
'((python :variables python-test-runner 'pytest)))
If you need both then you can set python-test-runner
to a list like this:
(setq-default dotspacemacs-configuration-layers
'((python :variables python-test-runner '(pytest nose))))
This means that pytest
is your primary test runner. To use the secondary test
runner you can call the test functions with a prefix argument e.g. SPC u SPC m
t t
to run one test with nose
.
To set project specific test runners you can set python-test-runner
in a
directory local variable in your project root. SPC f v d
in Spacemacs. See
the official documentation for more information.
The root of the project is detected with a .git
directory or a setup.cfg
file.
Buffer formatting
One of YAPF (the default) or black may be selected as the formatter, via
python-formatter
, as 'yapf
or 'black
respectively.
(setq-default dotspacemacs-configuration-layers '(
(python :variables python-formatter 'yapf)))
The key binding SPC m =
invokes the selected formatter on the current buffer
when in python mode.
Note that YAPF and black may also be invoked unconditionally via
yapfify-buffer
and blacken-buffer
, respectively, provided that they are
installed.
Automatic buffer formatting on save
To enable automatic buffer formatting on save set the variable
python-format-on-save
to t
. The formatter specified by python-formatter
will be used.
(setq-default dotspacemacs-configuration-layers '(
(python :variables python-format-on-save t)))
Automatic save of buffer when testing
By default a buffer is automatically saved before tests are executed upon it,
you can disable this feature by setting python-save-before-test
to nil
.
(setq-default dotspacemacs-configuration-layers '(
(python :variables python-save-before-test nil)))
autoflake
To be able to suppress unused imports easily, install autoflake:
pip install autoflake
pylookup
To use pylookup
on SPC m h H
, make sure you update the database first, using
SPC SPC pylookup-update
.
dap-mode debugger (only for lsp backend)
To use dap-mode
for debugging do:
pip install "ptvsd>=4.2"
Configuration
Fill column
If you want to customize the fill column value, use something like this inside
the user-init
function in your .spacemacs
:
(setq-default dotspacemacs-configuration-layers '(
(python :variables python-fill-column 99)))
Sort imports
If you want imports to be automatically sorted when you save a file (using
isort), set the python-sort-imports-on-save
variable in the python layer
config section:
(setq-default dotspacemacs-configuration-layers
'((python :variables python-sort-imports-on-save t)))
or as a directory-local variable (for per-project settings).
Importmagic
Install importmagic and epc for importmagic functionality.
pip install importmagic epc
Management of Python versions and virtual environments
Manage virtual environments with pyvenv
A virtual environment provides isolation of your Python package versions. For a
general overview see this site. Virtualenvwrapper which is also explained in the
previous link, is a program which manages your virtual environments in a central
location set by the WORKON_HOME
environment variable.
Spacemacs integration of virtual environments and virtualenvwrapper is provided by the pyvenv package. It provides the following key bindings:
Key binding | Description |
---|---|
SPC m V a |
activate a virtual environment in any directory |
SPC m V d |
deactivate active virtual environment |
SPC m V w |
work on virtual environment in WORKON_HOME |
Manage multiple Python versions with pyenv
If you need multiple Python versions (e.g. Python 2 and Python 3) then take a look at pyenv. It enables the installation and managment of multiple Python versions. This blogpost gives a good overview on how to use the tool. Spacemacs integration is provided by pyenv mode which has the following key bindings.
Key binding | Description |
---|---|
SPC m v s |
set a pyenv environment with pyenv |
SPC m v u |
unset a pyenv environment with pyenv |
Pyenv can also manage virtual environments for each of the Python versions it has installed. Those will be listed alongside your Python versions.
Automatic activation of local pyenv version
A project-specific pyenv version may be written to a file called
.python-version
using the pyenv local command.
Spacemacs can search in parent directories for this file, and automatically set
the pyenv version. The behavior can be set with the variable
python-auto-set-local-pyenv-version
to:
on-visit
(default) set the version when you visit a python buffer,on-project-switch
set the version when you switch projects,nil
to disable.
The same is also possible on pyvenv with a file called .venv
. The behavior
can be set with the variable python-auto-set-local-pyvenv-virtualenv=
to:
on-visit
(default) set the virtualenv when you visit a python buffer,on-project-switch
set the virtualenv when you switch projects,nil
to disable.
Key bindings
Inferior REPL process
Start a Python or iPython inferior REPL process with SPC m s i
.
If ipython
is available in system executable search paths, ipython
will be used to launch python shell; otherwise, default python
interpreter will be used. You may change your system executable
search path by activating a virtual environment.
Send code to inferior process commands:
Key binding | Description |
---|---|
SPC m s b |
send buffer and keep code buffer focused |
SPC m s B |
send buffer and switch to REPL in insert mode |
SPC m s f |
send function and keep code buffer focused |
SPC m s F |
send function and switch to REPL in insert mode |
SPC m s i |
start inferior REPL process |
SPC m s r |
send region and keep code buffer focused |
SPC m s R |
send region and switch to REPL in insert mode |
CTRL+j |
next item in REPL history |
CTRL+k |
previous item in REPL history |
Running Python Script in shell
To run a Python script like you would in the shell press SPC m c c
to start the Python script in comint mode. This is useful when working with
multiple Python files since the REPL does not reload changes made in other
modules.
Key binding | Description |
---|---|
SPC m c c |
Execute current file in a comint shell |
SPC m c C |
Execute current file in a comint shell and switch to it in insert state |
Note: With the universal argument SPC u
you can enter a new
compilation command.
Testing
Test commands start with m t
. To use the secondary test runner call the
function with a prefix argument, for example SPC u SPC m t a
.
No Debug | Description |
---|---|
SPC m t a |
launch all tests of the project |
SPC m t b |
launch all tests of the current buffer (same as module) |
SPC m t l |
launch last tests |
SPC m t m |
launch all tests of the current module |
SPC m t s |
launch all tests of the current suite (only with nose ) |
SPC m t t |
launch the current test (function) |
Debug | Description |
---|---|
SPC m t A |
launch all tests of the project in debug mode |
SPC m t B |
launch all tests of the current buffer (module) in debug mode |
SPC m t M |
launch all tests of the current module in debug mode |
SPC m t S |
launch all tests of the current suite in debug mode (only with nose ) |
SPC m t T |
launch the current test (function) in debug mode |
Refactoring
Key binding | Description |
---|---|
SPC m r f |
fix a missing import statement with importmagic |
SPC m r i |
remove unused imports with autoflake |
SPC m r I |
sort imports with isort |
Pip package management
In python buffer type SPC m P
to open buffer listing all installed pip
packages in the currently activated virtual environment.
Note: To open this menu from outside a python buffer type
SPC SPC pippel-list-packages RET
.
In the package list buffer:
Key binding | Description |
---|---|
RET |
follow link (pippel-menu-visit-homepage ) |
d |
mark for deletion (pippel-menu-mark-delete ) |
i |
prompt user for packages (pippel-install-package ) |
m |
remove mark (pippel-menu-mark-unmark ) |
r |
refresh package list (pippel-list-packages ) |
U |
mark all upgradable (pippel-menu-mark-all-upgrades ) |
u |
mark for upgrade (pippel-menu-mark-upgrade ) |
x |
perform marked package menu actions (pippel-menu-execute ) |
Live coding
Live coding is provided by the live-py-plugin.
Key binding | Description |
---|---|
SPC m l |
Toggle live-py-mode |
Other Python commands
Key binding | Description |
---|---|
SPC m = |
reformat the buffer using formatter specified in python-formatter |
SPC m d b |
toggle a breakpoint using wdb , ipdb , pudb , pdb or python3.7 (and above) |
SPC m g a |
go to assignment using anaconda-mode-find-assignments (C-o to jump back) |
SPC m g b |
jump back |
SPC m g g |
go to definition using anaconda-mode-find-definitions (C-o to jump back) |
SPC m g u |
navigate between usages with anaconda-mode-find-references |
SPC m h d |
look for documentation using helm-pydoc |
SPC m h h |
quick documentation using anaconda |
SPC m h H |
open documentation in firefox using pylookup |
SPC m v a |
activate a virtual environment in any directory |
SPC m v d |
deactivate active virtual environment |
SPC m v s |
set a pyenv environment with pyenv |
SPC m v u |
unset a pyenv environment with pyenv |
SPC m v w |
work on virtual environment in WORKON_HOME |
SPC m v p a |
activate pipenv in current project |
SPC m v p d |
deactivate pipenv in current project |
SPC m v p i |
install module into pipenv environment |
SPC m v p o |
open pipenv module in buffer |
SPC m v p s |
launch pipenv shell in current project |
SPC m v p u |
uninstall module from pipenv environment |
Debugger
Key binding | Description |
---|---|
SPC m d d d |
start debugging |
SPC m d d l |
debug last configuration |
SPC m d d r |
debug recent configuration |
SPC m d c |
continue |
SPC m d i |
step in |
SPC m d o |
step out |
SPC m d s |
next step |
SPC m d v |
inspect value at point |
SPC m d r |
restart frame |
SPC m d . |
debug transient state |
SPC m d a |
abandon current session |
SPC m d A |
abandon all process |
SPC m d e e |
eval |
SPC m d e r |
eval region |
SPC m d e t |
eval value at point |
SPC m d S s |
switch session |
SPC m d S t |
switch thread |
SPC m d S f |
switch frame |
SPC m d I i |
inspect |
SPC m d I r |
inspect region |
SPC m d I t |
inspect value at point |
SPC m d b b |
toggle a breakpoint |
SPC m d b c |
change breakpoint condition |
SPC m d b l |
change breakpoint log condition |
SPC m d b h |
change breakpoint hit count |
SPC m d b a |
add a breakpoint |
SPC m d b d |
delete a breakpoint |
SPC m d b D |
clear all breakpoints |
SPC m d '_ |
Run debug REPL |
SPC m d w l |
list local variables |
SPC m d w o |
goto output buffer if present |
SPC m d w s |
list sessions |
SPC m d w b |
list breakpoints |