Skip to content

CONTRIBUTING.md

Latest commit

 

History

History
387 lines (277 loc) · 11.1 KB

CONTRIBUTING.md

File metadata and controls

387 lines (277 loc) · 11.1 KB

Contributing Guide

We welcome all kinds of contributions. You don't need to be an expert in frontend or Python development to help out.

Checklist

Contributions are made through pull requests. Before sending a pull request, make sure to do the following:

Please reach out to the marimo team before starting work on a large contribution. Get in touch at GitHub issues or on Discord.

Prerequisites

To build marimo from source, you'll need to have Node.js, pnpm, GNU make, Python (>=3.9), and Hatch installed.

You can check for pre-requisites with:

make check-prereqs
  • Install Node.js >= 20
    • We use Node.js version 23
  • Install pnpm == 10.x
    • npm install -g pnpm@10
  • Install GNU Make (you may already have it installed)
  • Install Python >= 3.9. (You may already it installed. To see your version, use python -V at the command line.)
  • Install Hatch. Some installation options:
    • brew install hatch
    • pipx install hatch

And you'll need pre-commit to run some validation checks:

uv tool install pre-commit

You can optionally install pre-commit hooks to automatically run the validation checks when making a commit:

pre-commit install

You can conveniently create a pixi environment with all your development dependencies. These accomplish the next 3 things respectively:

  • Install and activate your development environment (node, pnpm, make, python, uv, hatch, pre-commit, pip)
  • Set up your front end and python environment
  • Start up your python environment using hatch You can simply run:
pixi shell 
make fe && make py 
hatch shell

After doing this, you can instantiate your marimo dev environment by running the following command:

make dev

Under the hood this runs the following 2 commands as 2 separate processes:

# in one terminal 
marimo edit --no-token --headless /tmp/nb.py # port 2718
# in another terminal 
cd frontend; pnpm dev # this will open at port 3000

Note

As an alternative to building from source, you can try developing in Gitpod. Note that developing in Gitpod is not officially supported by the marimo team.

Building from source

Be sure to install the dependencies above before building from source.

Build from source

After installing the dependencies, you can use either the traditional method (installing an editable wheel in your current venv) or use Hatch:

Traditional method:

make fe && make py

Using Hatch:

make fe
hatch shell

make fe builds the frontend. make py does an editable install of marimo, while hatch shell creates a Hatch environment with an editable install of marimo.

(All make commands should be run in the project's root directory.)

Building from source, unminified

To build the frontend unminified, run:

NODE_OPTIONS=--max_old_space_size=8192 NODE_ENV=development make fe -B

make commands

Command Category Description
help General 📖 Show available commands
install-all Setup 🚀 First-time setup: Install all dependencies (frontend & Python)
check-prereqs Setup ✓ Check if all required tools are installed
py Setup 🐍 Install Python dependencies in editable mode
fe Build 🔧 Build frontend assets
test Test 🧪 Run all tests (frontend, Python, end-to-end)
check Test 🧹 Run all checks
fe-check Lint/Test 🧹 Check frontend (lint, typecheck)
fe-test Test 🧪 Test frontend
e2e Test 🧪 Test end-to-end
fe-lint Lint 🧹 Lint frontend
fe-typecheck Lint 🔍 Typecheck frontend
fe-codegen Build 🔄 Generate frontend API
py-check Lint 🔍 Typecheck, lint, format python
typos Lint 🔍 Check for typos
py-test Test 🧪 Test python
py-snapshots Test 📸 Update snapshots
wheel Build 📦 Build wheel
docs Docs 📚 Build docs
docs-serve Docs 📚 Serve docs
storybook Docs 🧩 Start Storybook for UI development

Lint, Typecheck, Format

All checks.

make check

Frontend.

make fe-check

Python.

Using Make:

make py-check

Using Hatch:

hatch run lint
hatch run format
hatch run typecheck:check

Tests

We have frontend unit tests, Python unit tests, and end-to-end tests. Code changes should be accompanied by unit tests. Some changes should also be accompanied by end-to-end tests.

To run all tests:

make test

This can take some time. To run just frontend tests, just Python tests, or just end-to-end tests, read below.

Frontend

In the root directory, run:

make fe-test

Python

We use pytest syntax for Python tests.

Using Make

make py-test

Using Hatch

Run a specific test

hatch run test:test tests/_ast/

Run tests with optional dependencies

hatch run test-optional:test tests/_ast/

Run tests with a specific Python version

hatch run +py=3.10 test:test tests/_ast/
# or
hatch run +py=3.10 test-optional:test tests/_ast/

Run all tests across all Python versions

Not recommended since it takes a long time.

hatch run test:test

End-to-end

We use playwright to write and run end-to-end tests, which exercise both the marimo library and the frontend.

(The first time you run, you may be prompted by playwright to install some dependencies; follow those instructions.)

For best practices on writing end-to-end tests, check out the Best Practices doc.

For frontend tests, you want to build the frontend first with make fe so that Playwright works on your latest changes.

Run end-to-end tests.

In the root directory, run:

make e2e

Run tests interactively.

In frontend/:

pnpm playwright test --ui

Run a specific test.

In frontend/:

pnpm playwright test <filename> --ui
# e.g.
pnpm playwright test cells.test.ts --ui

or

pnpm playwright test --debug <filename>

Storybook

To open Storybook, run the following:

cd frontend/
pnpm storybook

Hot reloading / development mode

You can develop on marimo with hot reloading on the frontend and/or development mode on the server (which automatically restarts the server on code changes). These modes are especially helpful when you're making many small changes and want to see changes end-to-end very quickly.

For the frontend, you can run either

# starts a dev server on localhost:3000 and proxy requests to your marimo server
# has hot reloading and the fastest way to develop the frontend
# read caveats below
pnpm dev

OR

# OR, in order to test closer to production, you can build the frontend and watch for changes
pnpm build:watch

For the backend, we recommend running without auth (--no-token):

marimo edit --no-token
# or in debug mode
marimo -d edit --no-token
  • When to run with hot-reloading?: When you are developing on the frontend and want to see changes immediately. This is useful for styling, layout, new plugins, etc. Developing through the Vite server may have inconsistent behavior due to proxied api/websocket request and since the marimo Python server is not serving the HTML.
  • When to develop with the frontend in watch mode?: When you are making few frontend changes, or when you want to test the frontend in a way that is closer to production.
  • When to run marimo CLI with development mode?: When you are making changes to the backend and want to see debug logs. When developing on marimo plugins, you can run with "On module change" as "autorun" to see changes immediately.

Caveats for running pnpm dev

Running pnpm dev will serve the frontend from a Vite dev server, not from the marimo server. This means that:

  1. You will want to run your marimo server with --headless and --no-token so it does not open a new browser tab, as it will interfere with the frontend dev server.
  2. The tradeoff of using the frontend dev server is that it is faster to develop on the frontend, but you will not be able to test the frontend in the same way that it will be used in production.

Editor settings

If you use vscode, you might find the following settings.json useful:

{
  "editor.formatOnSave": true,
  "editor.formatOnPaste": false,
  "[typescript]": {
    "editor.defaultFormatter": "biomejs.biome"
  },
  "[typescriptreact]": {
    "editor.defaultFormatter": "biomejs.biome"
  }
}

Testing a branch from GitHub

This requires uv to be installed. This may take a bit to install frontend dependencies and build the frontend.

MARIMO_BUILD_FRONTEND=true \
uvx --with git+https://github.com/marimo-team/marimo.git@BRANCH_NAME \
marimo edit

Additionally, you can run marimo from the main branch:

MARIMO_BUILD_FRONTEND=true \
uvx --with git+https://github.com/marimo-team/marimo.git \
marimo edit

Your first PR

Marimo has a variety of CI jobs that run on pull requests. All new PRs will fail until you have signed the CLA. Don't fret. You can sign the CLA by leaving a comment in the PR with text of I have read the CLA Document and I hereby sign the CLA