--- title: Development How-tos hide_title: true sidebar_position: 4 version: 1 --- # Development How-tos ## Contributing to Documentation The latest documentation and tutorial are available at https://superset.apache.org/. The documentation site is built using [Docusaurus 2](https://docusaurus.io/), a modern static website generator, the source for which resides in `./docs`. ### Local Development To set up a local development environment with hot reloading for the documentation site: ```shell cd docs yarn install # Installs NPM dependencies yarn start # Starts development server at http://localhost:3000 ``` ### Build To create and serve a production build of the documentation site: ```shell yarn build yarn serve ``` ### Deployment Commits to `master` trigger a rebuild and redeploy of the documentation site. Submit pull requests that modify the documentation with the `docs:` prefix. ## Creating Visualization Plugins Visualizations in Superset are implemented in JavaScript or TypeScript. Superset comes preinstalled with several visualizations types (hereafter "viz plugins") that can be found under the `superset-frontend/plugins` directory. Viz plugins are added to the application in the `superset-frontend/src/visualizations/presets/MainPreset.js`. The Superset project is always happy to review proposals for new high quality viz plugins. However, for highly custom viz types it is recommended to maintain a fork of Superset, and add the custom built viz plugins by hand. **Note:** Additional community-generated resources about creating and deploying custom visualization plugins can be found on the [Superset Wiki](https://github.com/apache/superset/wiki/Community-Resource-Library#creating-custom-data-visualizations) ### Prerequisites In order to create a new viz plugin, you need the following: - Run MacOS or Linux (Windows is not officially supported, but may work) - Node.js 16 - npm 7 or 8 A general familiarity with [React](https://reactjs.org/) and the npm/Node system is also recommended. ### Creating a simple Hello World viz plugin To get started, you need the Superset Yeoman Generator. It is recommended to use the version of the template that ships with the version of Superset you are using. This can be installed by doing the following: ```bash npm i -g yo cd superset-frontend/packages/generator-superset npm i npm link ``` After this you can proceed to create your viz plugin. Create a new directory for your viz plugin with the prefix `superset-plugin-chart` and run the Yeoman generator: ```bash mkdir /tmp/superset-plugin-chart-hello-world cd /tmp/superset-plugin-chart-hello-world ``` Initialize the viz plugin: ```bash yo @superset-ui/superset ``` After that the generator will ask a few questions (the defaults should be fine): ```bash $ yo @superset-ui/superset _-----_ ╭──────────────────────────╮ | | │ Welcome to the │ |--(o)--| │ generator-superset │ `---------´ │ generator! │ ( _´U`_ ) ╰──────────────────────────╯ /___A___\ / | ~ | __'.___.'__ ´ ` |° ´ Y ` ? Package name: superset-plugin-chart-hello-world ? Description: Hello World ? What type of chart would you like? Time-series chart create package.json create .gitignore create babel.config.js create jest.config.js create README.md create tsconfig.json create src/index.ts create src/plugin/buildQuery.ts create src/plugin/controlPanel.ts create src/plugin/index.ts create src/plugin/transformProps.ts create src/types.ts create src/SupersetPluginChartHelloWorld.tsx create test/index.test.ts create test/__mocks__/mockExportString.js create test/plugin/buildQuery.test.ts create test/plugin/transformProps.test.ts create types/external.d.ts create src/images/thumbnail.png ``` To build the viz plugin, run the following commands: ```bash npm i --force npm run build ``` Alternatively, to run the viz plugin in development mode (=rebuilding whenever changes are made), start the dev server with the following command: ```bash npm run dev ``` To add the package to Superset, go to the `superset-frontend` subdirectory in your Superset source folder run ```bash npm i -S /tmp/superset-plugin-chart-hello-world ``` If you publish your package to npm, you can naturally install directly from there, too. After this edit the `superset-frontend/src/visualizations/presets/MainPreset.js` and make the following changes: ```js import { SupersetPluginChartHelloWorld } from 'superset-plugin-chart-hello-world'; ``` to import the viz plugin and later add the following to the array that's passed to the `plugins` property: ```js new SupersetPluginChartHelloWorld().configure({ key: 'ext-hello-world' }), ``` After that the viz plugin should show up when you run Superset, e.g. the development server: ```bash npm run dev-server ``` ## Testing ### Python Testing `pytest`, backend by docker-compose is how we recommend running tests locally. For a more complex test matrix (against different database backends, python versions, ...) you can rely on our GitHub Actions by simply opening a draft pull request. Note that the test environment uses a temporary directory for defining the SQLite databases which will be cleared each time before the group of test commands are invoked. There is also a utility script included in the Superset codebase to run python integration tests. The [readme can be found here](https://github.com/apache/superset/tree/master/scripts/tests) To run all integration tests for example, run this script from the root directory: ```bash scripts/tests/run.sh ``` You can run unit tests found in './tests/unit_tests' for example with pytest. It is a simple way to run an isolated test that doesn't need any database setup ```bash pytest ./link_to_test.py ``` #### Testing with local Presto connections If you happen to change db engine spec for Presto/Trino, you can run a local Presto cluster with Docker: ```bash docker run -p 15433:15433 starburstdata/presto:350-e.6 ``` Then update `SUPERSET__SQLALCHEMY_EXAMPLES_URI` to point to local Presto cluster: ```bash export SUPERSET__SQLALCHEMY_EXAMPLES_URI=presto://localhost:15433/memory/default ``` ### Frontend Testing We use [Jest](https://jestjs.io/) and [Enzyme](https://airbnb.io/enzyme/) to test TypeScript/JavaScript. Tests can be run with: ```bash cd superset-frontend npm run test ``` To run a single test file: ```bash npm run test -- path/to/file.js ``` ### e2e Integration Testing For e2e testing, we recommend that you use a `docker-compose` backed-setup Alternatively, you can go lower level and set things up in your development environment by following these steps: First set up a python/flask backend: ```bash export SUPERSET_CONFIG=tests.integration_tests.superset_test_config export SUPERSET_TESTENV=true export CYPRESS_BASE_URL="http://localhost:8081" superset db upgrade superset load_test_users superset init superset load-examples --load-test-data superset run --port 8081 ``` In another terminal, prepare the frontend and run Cypress tests: ```bash cd superset-frontend npm run build-instrumented cd cypress-base npm install # run tests via headless Chrome browser (requires Chrome 64+) npm run cypress-run-chrome # run tests from a specific file npm run cypress-run-chrome -- --spec cypress/e2e/explore/link.test.ts # run specific file with video capture npm run cypress-run-chrome -- --spec cypress/e2e/dashboard/index.test.js --config video=true # to open the cypress ui npm run cypress-debug # to point cypress to a url other than the default (http://localhost:8088) set the environment variable before running the script # e.g., CYPRESS_BASE_URL="http://localhost:9000" CYPRESS_BASE_URL= npm run cypress open ``` See [`superset-frontend/cypress_build.sh`](https://github.com/apache/superset/blob/master/superset-frontend/cypress_build.sh). As an alternative you can use docker compose environment for testing: Make sure you have added below line to your /etc/hosts file: `127.0.0.1 db` If you already have launched Docker environment please use the following command to assure a fresh database instance: `docker compose down -v` Launch environment: `CYPRESS_CONFIG=true docker compose up` It will serve backend and frontend on port 8088. Run Cypress tests: ```bash cd cypress-base npm install npm run cypress open ``` ### Debugging Server App Follow these instructions to debug the Flask app running inside a docker container. First add the following to the ./docker-compose.yaml file ```diff superset: env_file: docker/.env image: *superset-image container_name: superset_app command: ["/app/docker/docker-bootstrap.sh", "app"] restart: unless-stopped + cap_add: + - SYS_PTRACE ports: - 8088:8088 + - 5678:5678 user: "root" depends_on: *superset-depends-on volumes: *superset-volumes environment: CYPRESS_CONFIG: "${CYPRESS_CONFIG}" ``` Start Superset as usual ```bash docker compose up ``` Install the required libraries and packages to the docker container Enter the superset_app container ```bash docker exec -it superset_app /bin/bash root@39ce8cf9d6ab:/app# ``` Run the following commands inside the container ```bash apt update apt install -y gdb apt install -y net-tools pip install debugpy ``` Find the PID for the Flask process. Make sure to use the first PID. The Flask app will re-spawn a sub-process every time you change any of the python code. So it's important to use the first PID. ```bash ps -ef UID PID PPID C STIME TTY TIME CMD root 1 0 0 14:09 ? 00:00:00 bash /app/docker/docker-bootstrap.sh app root 6 1 4 14:09 ? 00:00:04 /usr/local/bin/python /usr/bin/flask run -p 8088 --with-threads --reload --debugger --host=0.0.0.0 root 10 6 7 14:09 ? 00:00:07 /usr/local/bin/python /usr/bin/flask run -p 8088 --with-threads --reload --debugger --host=0.0.0.0 ``` Inject debugpy into the running Flask process. In this case PID 6. ```bash python3 -m debugpy --listen 0.0.0.0:5678 --pid 6 ``` Verify that debugpy is listening on port 5678 ```bash netstat -tunap Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:5678 0.0.0.0:* LISTEN 462/python tcp 0 0 0.0.0.0:8088 0.0.0.0:* LISTEN 6/python ``` You are now ready to attach a debugger to the process. Using VSCode you can configure a launch configuration file .vscode/launch.json like so. ```json { "version": "0.2.0", "configurations": [ { "name": "Attach to Superset App in Docker Container", "type": "python", "request": "attach", "connect": { "host": "127.0.0.1", "port": 5678 }, "pathMappings": [ { "localRoot": "${workspaceFolder}", "remoteRoot": "/app" } ] }, ] } ``` VSCode will not stop on breakpoints right away. We've attached to PID 6 however it does not yet know of any sub-processes. In order to "wakeup" the debugger you need to modify a python file. This will trigger Flask to reload the code and create a new sub-process. This new sub-process will be detected by VSCode and breakpoints will be activated. ### Debugging Server App in Kubernetes Environment To debug Flask running in POD inside a kubernetes cluster, you'll need to make sure the pod runs as root and is granted the `SYS_TRACE` capability. These settings should not be used in production environments. ```yaml securityContext: capabilities: add: ["SYS_PTRACE"] ``` See [set capabilities for a container](https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#set-capabilities-for-a-container) for more details. Once the pod is running as root and has the `SYS_PTRACE` capability it will be able to debug the Flask app. You can follow the same instructions as in `docker compose`. Enter the pod and install the required library and packages; gdb, netstat and debugpy. Often in a Kubernetes environment nodes are not addressable from outside the cluster. VSCode will thus be unable to remotely connect to port 5678 on a Kubernetes node. In order to do this you need to create a tunnel that port forwards 5678 to your local machine. ```bash kubectl port-forward pod/superset- 5678:5678 ``` You can now launch your VSCode debugger with the same config as above. VSCode will connect to to 127.0.0.1:5678 which is forwarded by kubectl to your remote kubernetes POD. ### Storybook Superset includes a [Storybook](https://storybook.js.org/) to preview the layout/styling of various Superset components, and variations thereof. To open and view the Storybook: ```bash cd superset-frontend npm run storybook ``` When contributing new React components to Superset, please try to add a Story alongside the component's `jsx/tsx` file. ## Contributing Translations We use [Flask-Babel](https://python-babel.github.io/flask-babel/) to translate Superset. In Python files, we use the following [translation functions](https://python-babel.github.io/flask-babel/#using-translations) from `Flask-Babel`: - `gettext` and `lazy_gettext` (usually aliased to `_`): for translating singular strings. - `ngettext`: for translating strings that might become plural. ```python from flask_babel import lazy_gettext as _ ``` then wrap the translatable strings with it, e.g. `_('Translate me')`. During extraction, string literals passed to `_` will be added to the generated `.po` file for each language for later translation. At runtime, the `_` function will return the translation of the given string for the current language, or the given string itself if no translation is available. In TypeScript/JavaScript, the technique is similar: we import `t` (simple translation), `tn` (translation containing a number). ```javascript import { t, tn } from "@superset-ui/translation"; ``` ### Enabling language selection Add the `LANGUAGES` variable to your `superset_config.py`. Having more than one option inside will add a language selection dropdown to the UI on the right side of the navigation bar. ```python LANGUAGES = { 'en': {'flag': 'us', 'name': 'English'}, 'fr': {'flag': 'fr', 'name': 'French'}, 'zh': {'flag': 'cn', 'name': 'Chinese'}, } ``` ### Creating a new language dictionary First check if the language code for your target language already exists. Check if the [two letter ISO 639-1 code](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) for your target language already exists in the `superset/translations` directory: ```bash ls superset/translations | grep -E "^[a-z]{2}\/" ``` If your language already has a preexisting translation, skip to the next section The following languages are already supported by Flask AppBuilder, and will make it easier to translate the application to your target language: [Flask AppBuilder i18n documentation](https://flask-appbuilder.readthedocs.io/en/latest/i18n.html) To create a dictionary for a new language, first make sure the necessary dependencies are installed: ```bash pip install -r superset/translations/requirements.txt ``` Then run the following, where `LANGUAGE_CODE` is replaced with the language code for your target language: ```bash pybabel init -i superset/translations/messages.pot -d superset/translations -l LANGUAGE_CODE ``` For instance, to add a translation for Finnish (language code `fi`), run the following: ```bash pybabel init -i superset/translations/messages.pot -d superset/translations -l fi ``` ### Extracting new strings for translation Periodically, when working on translations, we need to extract the strings from both the backend and the frontend to compile a list of all strings to be translated. It doesn't happen automatically and is a required step to gather the strings and get them into the `.po` files where they can be translated, so that they can then be compiled. This script does just that: ```bash ./scripts/translations/babel_update.sh ``` ### Updating language files Run the following command to update the language files with the new extracted strings. ```bash pybabel update -i superset/translations/messages.pot -d superset/translations --ignore-obsolete ``` You can then translate the strings gathered in files located under `superset/translation`, where there's one folder per language. You can use [Poedit](https://poedit.net/features) to translate the `po` file more conveniently. Here is [a tutorial](https://web.archive.org/web/20220517065036/https://wiki.lxde.org/en/Translate_*.po_files_with_Poedit). To perform the translation on MacOS, you can install `poedit` via Homebrew: ```bash brew install poedit ``` After this, just start the `poedit` application and open the `messages.po` file. In the case of the Finnish translation, this would be `superset/translations/fi/LC_MESSAGES/messages.po`. ### Applying translations To make the translations available on the frontend, we need to convert the PO file into a collection of JSON files. To convert all PO files to formatted JSON files you can use the `build-translation` script ```bash # Install dependencies if you haven't already cd superset-frontend/ && npm ci # Compile translations for the frontend npm run build-translation ``` Finally, for the translations to take effect we need to compile translation catalogs into binary MO files for the backend using `pybabel`. ```bash # inside the project root pybabel compile -d superset/translations ``` ## Linting ### Python We use [ruff](https://github.com/astral-sh/ruff) for linting which can be invoked via: ``` # auto-reformat using ruff ruff format # lint check with ruff ruff check # lint fix with ruff ruff check --fix ``` Ruff configuration is located in our (pyproject.toml)[https://github.com/apache/superset/blob/master/pyproject.toml] file All this is configured to run in pre-commit hooks, which we encourage you to setup with `pre-commit install` ### TypeScript ```bash cd superset-frontend npm ci # run eslint checks npm run eslint -- . # run tsc (typescript) checks npm run type ``` If using the eslint extension with vscode, put the following in your workspace `settings.json` file: ```json "eslint.workingDirectories": [ "superset-frontend" ] ```