14 KiB
Configuring Python in Emacs
A literate programming file for configuring Python.
Introduction
The critical part of Python integration with Emacs is running LSP in Python using direnv. And the question to ask is if the Python we run it in Docker or in a virtual environment.
While Emacs supplies a Python editing environment, we’ll still use use-package to grab the latest:
(use-package python
:after flycheck
:mode ("[./]flake8\\'" . conf-mode)
:mode ("/Pipfile\\'" . conf-mode)
:init
(setq python-indent-guess-indent-offset-verbose nil
flycheck-flake8-maximum-line-length 120)
:config
(when (and (executable-find "ipython")
(string= python-shell-interpreter "ipython"))
(setq python-shell-interpreter "ipython"))
(flycheck-add-next-checker 'python-pylint 'python-pycompile 'append))Note: Install the following checks:
pip install flake8 pylint pyright mypy pycompileOr better yet, add those to the requirements-dev.txt file.
All the above loveliness can be easily accessible with a major-mode-hydra defined for emacs-lisp-mode:
(use-package major-mode-hydra
:config
(defvar ha-python-eval-title (font-icons 'mdicon "run" :title "Python Evaluation"))
(defvar ha-python-goto-title (font-icons 'faicon "python" :title "Python Symbol References"))
(pretty-hydra-define python-evaluate (:color blue :quit-key "q"
:title ha-python-eval-title)
("Section"
(("f" python-shell-send-defun "Function/Class")
("e" python-shell-send-statement "Line")
(";" python-shell-send-string "Expression"))
"Entirety"
(("F" python-shell-send-file "File")
("B" python-shell-send-buffer "Buffer")
("r" python-shell-send-region "Region"))))
(pretty-hydra-define python-goto (:color blue :quit-key "q"
:title ha-python-goto-title)
("Symbols"
(("s" xref-find-apropos "Find Symbol")
("e" python-shell-send-statement "Line")
(";" python-shell-send-string "Expression"))
"Entirety"
(("F" python-shell-send-file "File")
("B" python-shell-send-buffer "Buffer")
("r" python-shell-send-region "Region"))))
(major-mode-hydra-define python-mode (:quit-key "q" :color blue)
("Server"
(("S" run-python "Start Server")
("s" python-shell-switch-to-shell "Go to Server"))
"Edit"
(("r" iedit-mode "Rename")
(">" python-indent-shift-left "Shift Left")
("<" python-indent-shift-right "Shift Right"))
"Navigate/Eval"
(("e" python-evaluate/body "Evaluate...")
("g" python-goto/body "Go to..."))
"Docs"
(("d" python-eldoc-at-point "Docs on Symbol")
("D" python-describe-at-point "Describe Symbol")))))Virtual Environment
For a local virtual machine, put the following in your .envrc file:
layout_python3That is pretty slick and simple.
The old way, that we still use if you need a particular version of Python, is to install pyenv globally:
pip install pyenv
And have this in your .envrc file:
use python 3.7.1
Also, you need the following in your ~/.config/direnv/direnvrc file (which I have):
use_python() {
local python_root=$(pyenv root)/versions/$1
load_prefix "$python_root"
if [[ -x "$python_root/bin/python" ]]; then
layout python "$python_root/bin/python"
else
echo "Error: $python_root/bin/python can't be executed."
exit
fi
}Editing Python Code
Let’s integrate this Python support for evil-text-object project:
(when (fboundp 'evil-define-text-object)
(use-package evil-text-object-python
:hook (python-mode . evil-text-object-python-add-bindings)))This allows me to delete a Python “block” using dal.
Docker Environment
Docker really allows you to isolate your project's environment. The downside is that you are using Docker and probably a bloated container. On my work laptop, a Mac, this creates a behemoth virtual machine that immediately spins the fans like a wind tunnel.
But, but… think of the dependencies!
Enough of the rant (I go back and forth), after getting Docker installed and running (ooo Podman … shiny), and you've created a Dockerfile for your project, let's install container-env.
Your project's .envrc file would contain something like:
CONTAINER_NAME=my-docker-container
CONTAINER_WRAPPERS=(python3 pip3 yamllint)
CONTAINER_EXTRA_ARGS="--env SOME_ENV_VAR=${SOME_ENV_VAR}"
container_layoutUnit Tests
(use-package python-pytest
:after python
:commands python-pytest-dispatch
:init
(use-package major-mode-hydra
:config
(defvar ha-python-tests-title (font-icons 'devicon "pytest" :title "Python Test Framework"))
(pretty-hydra-define python-tests (:color blue :quit-key "q"
:title ha-python-tests-title)
("Suite"
(("a" python-pytest "All")
("f" python-pytest-file-dwim "File DWIM")
("F" python-pytest-file "File"))
"Specific"
(("d" python-pytest-function-dwim "Function DWIM")
("D" python-pytest-function "Function"))
"Again"
(("r" python-pytest-repeat "Repeat tests")
("p" python-pytest-dispatch "Dispatch"))))
(major-mode-hydra-define+ python-mode (:quit-key "q" :color blue)
("Misc"
(("t" python-tests/body "Tests..."))))))Python Dependencies
Each Python project's requirements-dev.txt file would reference the python-lsp-server (not the unmaintained project, python-language-server):
python-lsp-server[all]
Note: This does mean, you would have a tox.ini with this line:
[tox]
minversion = 1.6
skipsdist = True
envlist = linters
ignore_basepython_conflict = True
[testenv]
basepython = python3
install_command = pip install {opts} {packages}
deps = -r{toxinidir}/test-requirements.txt
commands = stestr run {posargs}
stestr slowest
# ...Pyright
I’m using the Microsoft-supported pyright package instead. Adding this to my requirements.txt files:
pyrightThe pyright package works with LSP.
(use-package lsp-pyright
:hook (python-mode . (lambda () (require 'lsp-pyright)))
:init (when (executable-find "python3")
(setq lsp-pyright-python-executable-cmd "python3")))LSP Integration of Python
Now that the LSP Integration is complete, we can stitch the two projects together, by calling lsp. I oscillate between automatically turning on LSP mode with every Python file, but I sometimes run into issues when starting, so I conditionally turn it on.
(defvar ha-python-lsp-title (font-icons 'faicon "python" :title "Python LSP"))
(defun ha-setup-python-lsp ()
"Configure the keybindings for LSP in Python."
(interactive)
(pretty-hydra-define python-lsp (:color blue :quit-key "q"
:title ha-python-lsp-title)
("Server"
(("D" lsp-disconnect "Disconnect")
("R" lsp-workspace-restart "Restart")
("S" lsp-workspace-shutdown "Shutdown")
("?" lsp-describe-session "Describe"))
"Refactoring"
(("a" lsp-execute-code-action "Code Actions")
("o" lsp-organize-imports "Organize Imports")
("l" lsp-avy-lens "Avy Lens"))
"Toggles"
(("b" lsp-headerline-breadcrumb-mode "Breadcrumbs")
("d" lsp-ui-doc-mode "Documentation Popups")
("m" lsp-modeline-diagnostics-mode "Modeline Diagnostics")
("s" lsp-ui-sideline-mode "Sideline Mode"))
""
(("t" lsp-toggle-on-type-formatting "Type Formatting")
("h" lsp-toggle-symbol-highlight "Symbol Highlighting")
("L" lsp-toggle-trace-io "Log I/O"))))
(pretty-hydra-define+ python-goto (:quit-key "q")
("LSP"
(("g" lsp-find-definition "Definition")
("d" lsp-find-declaration "Declaration")
("r" lsp-find-references "References")
("t" lsp-find-type-definition "Type Definition"))
"Peek"
(("D" lsp-ui-peek-find-definitions "Definitions")
("I" lsp-ui-peek-find-implementation "Implementations")
("R" lsp-ui-peek-find-references "References")
("S" lsp-ui-peek-find-workspace-symbol "Symbols"))
"LSP+"
(("u" lsp-ui-imenu "UI Menu")
("i" lsp-find-implementation "Implementations")
("h" lsp-treemacs-call-hierarchy "Hierarchy")
("E" lsp-treemacs-errors-list "Error List"))))
(major-mode-hydra-define+ python-mode nil
("Server"
(("l" python-lsp/body "LSP..."))
"Edit"
(("r" lsp-rename "Rename")
("=" lsp-format-region "Format"))
"Navigate"
(("A" lsp-workspace-folders-add "Add Folder")
("R" lsp-workspace-folders-remove "Remove Folder"))
"Docs"
(("D" lsp-describe-thing-at-point "Describe LSP Symbol")
("h" lsp-ui-doc-glance "Glance Help")
("H" lsp-document-highlight "Highlight"))))
(call-interactively 'lsp))
(use-package lsp-mode
:config
(major-mode-hydra-define+ python-mode (:quit-key "q")
("Server"
(("L" ha-setup-python-lsp "Start LSP Server")))))
;; ----------------------------------------------------------------------
;; Missing Symbols to be integrated?
;; "0" '("treemacs" . lsp-treemacs-symbols)
;; "/" '("complete" . completion-at-point)
;; "k" '("check code" . python-check)
;; "Fb" '("un-blacklist folder" . lsp-workspace-blacklist-remove)
;; "hs" '("signature help" . lsp-signature-activate)
;; "tT" '("toggle treemacs integration" . lsp-treemacs-sync-mode)
;; "ta" '("toggle modeline code actions" . lsp-modeline-code-actions-mode)
;; "th" '("toggle highlighting" . lsp-toggle-symbol-highlight)
;; "tl" '("toggle lenses" . lsp-lens-mode)
;; "ts" '("toggle signature" . lsp-toggle-signature-auto-activate)Project Configuration
I work with a lot of projects with my team where I need to configure the project such that LSP and my Emacs setup works. Let's suppose I could point a function at a project directory, and have it set it up:
(defun ha-python-configure-project (proj-directory)
"Configure PROJ-DIRECTORY for LSP and Python."
(interactive "DPython Project: ")
(let ((default-directory proj-directory))
(unless (f-exists? ".envrc")
(message "Configuring direnv")
(with-temp-file ".envrc"
;; (insert "use_python 3.7.4\n")
(insert "layout_python3\n"))
(direnv-allow))
(unless (f-exists? ".pip.conf")
(message "Configuring pip")
(with-temp-file ".pip.conf"
(insert "[global]\n")
(insert "index-url = https://pypi.python.org/simple\n"))
(shell-command "pipconf --local")
(shell-command "pip install --upgrade pip"))
(message "Configuring pip for LSP")
(with-temp-file "requirements-dev.txt"
(insert "python-lsp-server[all]\n")
;; Let's install these extra packages individually ...
(insert "pyls-flake8\n")
;; (insert "pylsp-mypy")
;; (insert "pyls-isort")
;; (insert "python-lsp-black")
;; (insert "pyls-memestra")
(insert "pylsp-rope\n"))
(shell-command "pip install -r requirements-dev.txt")))