superset/CONTRIBUTING.md

# Contributing

Contributions are welcome and are greatly appreciated! Every
little bit helps, and credit will always be given.

You can contribute in many ways:

## Types of Contributions

### Report Bugs

Report bugs through GitHub

If you are reporting a bug, please include:

-   Your operating system name and version.
-   Any details about your local setup that might be helpful in
    troubleshooting.
-   Detailed steps to reproduce the bug.

When you post python stack traces please quote them using
[markdown blocks](https://help.github.com/articles/creating-and-highlighting-code-blocks/).

### Fix Bugs

Look through the GitHub issues for bugs. Anything tagged with "bug" is
open to whoever wants to implement it.

### Implement Features

Look through the GitHub issues for features. Anything tagged with
"feature" or "starter_task" is open to whoever wants to implement it.

### Documentation

Superset could always use better documentation,
whether as part of the official Superset docs,
in docstrings, `docs/*.rst` or even on the web as blog posts or
articles.

To build the docs, simply run ``./build.sh`` from the ``docs/`` folder.
The rendered docs are accessible at `http://localhost:{PORT}/static/assets/docs/faq.html`.

### Submit Feedback

The best way to send feedback is to file an issue on GitHub.

If you are proposing a feature:

-   Explain in detail how it would work.
-   Keep the scope as narrow as possible, to make it easier to
    implement.
-   Remember that this is a volunteer-driven project, and that
    contributions are welcome :)

### Questions

There is a dedicated [tag](https://stackoverflow.com/questions/tagged/apache-superset) on [stackoverflow](https://stackoverflow.com/). Please use it when asking questions.

## Pull Request Guidelines

Before you submit a pull request from your forked repo, check that it
meets these guidelines:

1.  The pull request should include tests, either as doctests,
    unit tests, or both.
2.  Run `tox` and resolve all errors and test failures.
3.  If the pull request adds functionality, the docs should be updated
    as part of the same PR. Doc string are often sufficient, make
    sure to follow the sphinx compatible standards.
4.  The pull request should work for Python 2.7 and Python 3.6.
    ``from __future__ import`` will be required in every `.py` file soon.
5.  If the pull request adds a Python dependency include it in `setup.py`
    denoting any specific restrictions and in `requirements.txt` pinned to a
    specific version which ensures that the application build is deterministic.
6.  Please rebase and resolve all conflicts before submitting.
7.  Please ensure the necessary checks pass and that code coverage does not
    decrease.
8.  If you are asked to update your pull request with some changes there's
    no need to create a new one. Push your changes to the same branch.

## Documentation

The latest documentation and tutorial are available [here](https://superset.incubator.apache.org/).

Contributing to the official documentation is relatively easy, once you've setup
your environment and done an edit end-to-end. The docs can be found in the
`docs/` subdirectory of the repository, and are written in the
[reStructuredText format](https://en.wikipedia.org/wiki/ReStructuredText) (.rst).
If you've written Markdown before, you'll find the reStructuredText format familiar.

Superset uses [Sphinx](http://www.sphinx-doc.org/en/1.5.1/) to convert the rst files
in `docs/` to the final HTML output users see.

Before you start changing the docs, you'll want to
[fork the Superset project on Github](https://help.github.com/articles/fork-a-repo/).
Once that new repository has been created, clone it on your local machine:

    git clone git@github.com:your_username/incubator-superset.git

At this point, you may also want to create a
[Python virtual environment](http://docs.python-guide.org/en/latest/dev/virtualenvs/)
to manage the Python packages you're about to install:

    virtualenv superset-dev
    source superset-dev/bin/activate

Finally, to make changes to the rst files and build the docs using Sphinx,
you'll need to install a handful of dependencies from the repo you cloned:

    cd incubator-superset
    pip install -r docs/requirements.txt

To get the feel for how to edit and build the docs, let's edit a file, build
the docs and see our changes in action. First, you'll want to
[create a new branch](https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging)
to work on your changes:

    git checkout -b changes-to-docs

Now, go ahead and edit one of the files under `docs/`, say `docs/tutorial.rst`
- change it however you want. Check out the
[ReStructuredText Primer](http://docutils.sourceforge.net/docs/user/rst/quickstart.html)
for a reference on the formatting of the rst files.

Once you've made your changes, run this command from the root of the Superset
repo to convert the docs into HTML:

    python setup.py build_sphinx

You'll see a lot of output as Sphinx handles the conversion. After it's done, the
HTML Sphinx generated should be in `docs/_build/html`. Go ahead and navigate there
and start a simple web server so we can check out the docs in a browser:

    cd docs/_build/html
    python -m SimpleHTTPServer

This will start a small Python web server listening on port 8000. Point your
browser to [http://localhost:8000/](http://localhost:8000/), find the file
you edited earlier, and check out your changes!

If you've made a change you'd like to contribute to the actual docs, just commit
your code, push your new branch to Github:

    git add docs/tutorial.rst
    git commit -m 'Awesome new change to tutorial'
    git push origin changes-to-docs

Then, [open a pull request](https://help.github.com/articles/about-pull-requests/).

If you're adding new images to the documentation, you'll notice that the images
referenced in the rst, e.g.

    .. image:: _static/img/tutorial/tutorial_01_sources_database.png

aren't actually included in that directory. _Instead_, you'll want to add and commit
images (and any other static assets) to the _superset/assets/images_ directory.
When the docs are being pushed to [Apache Superset (incubating)](https://superset.incubator.apache.org/), images
will be moved from there to the _\_static/img_ directory, just like they're referenced
in the docs.

For example, the image referenced above actually lives in

    superset/assets/images/tutorial

Since the image is moved during the documentation build process, the docs reference the
image in

    _static/img/tutorial

instead.

## Setting up a Python development environment

Check the [OS dependencies](https://superset.incubator.apache.org/installation.html#os-dependencies) before follows these steps.

    # fork the repo on GitHub and then clone it
    # alternatively you may want to clone the main repo but that won't work
    # so well if you are planning on sending PRs
    # git clone git@github.com:apache/incubator-superset.git

    # [optional] setup a virtual env and activate it
    virtualenv env
    source env/bin/activate

    # install for development
    pip install -r requirements.txt
    pip install -e .

    # Create an admin user
    fabmanager create-admin --app superset

    # Initialize the database
    superset db upgrade

    # Create default roles and permissions
    superset init

    # Load some data to play with
    superset load_examples

    # start a dev web server
    superset runserver -d


### Logging to the browser console (Python 3 only)

When debugging your application, you can have the server logs sent directly to the browser console:

    superset runserver -d --console-log

You can log anything to the browser console, including objects:

    from superset import app
    app.logger.error('An exception occurred!')
    app.logger.info(form_data)


## Setting up the node / npm javascript environment

`superset/assets` contains all npm-managed, front end assets.
Flask-Appbuilder itself comes bundled with jQuery and bootstrap.
While these may be phased out over time, these packages are currently not
managed with npm.

### Node/npm versions
Make sure you are using recent versions of node and npm. No problems have been found with node>=5.10 and 4.0. > npm>=3.9.

### Using npm to generate bundled files

#### npm
First, npm must be available in your environment. If it is not you can run the following commands
(taken from [this source](https://gist.github.com/DanHerbert/9520689))
```
brew install node --without-npm
echo prefix=~/.npm-packages >> ~/.npmrc
curl -L https://www.npmjs.com/install.sh | sh
```

The final step is to add `~/.npm-packages/bin` to your `PATH` so commands you install globally are usable.
Add something like this to your `.bashrc` file, then `source ~/.bashrc` to reflect the change.
```
export PATH="$HOME/.npm-packages/bin:$PATH"
```

#### npm packages
To install third party libraries defined in `package.json`, run the
following within the `superset/assets/` directory which will install them in a
new `node_modules/` folder within `assets/`.

```bash
# from the root of the repository, move to where our JS package.json lives
cd superset/assets/
# install yarn, a replacement for `npm install` that is faster and more deterministic
npm install -g yarn
# run yarn to fetch all the dependencies
yarn
```

To parse and generate bundled files for superset, run either of the
following commands. The `dev` flag will keep the npm script running and
re-run it upon any changes within the assets directory.

```
# Copies a conf file from the frontend to the backend
npm run sync-backend

# Compiles the production / optimized js & css
npm run prod

# Start a web server that manages and updates your assets as you modify them
npm run dev
```

For every development session you will have to start a flask dev server
as well as an npm watcher

```
superset runserver -d -p 8081
npm run dev
```

#### Upgrading npm packages

Should you add or upgrade a npm package, which involves changing `package.json`, you'll need to re-run `yarn install` and push the newly generated `yarn.lock` file so we get the reproducible build. More information at (https://yarnpkg.com/blog/2016/11/24/lockfiles-for-all/)

## Testing
All tests are carried out in [tox](http://tox.readthedocs.io/en/latest/index.html)
a standardized testing framework mostly for Python (though we also used it for Javascript).
All python tests can be run with any of the tox [environments](http://tox.readthedocs.io/en/latest/example/basic.html#a-simple-tox-ini-default-environments), via,

    tox -e <environment>

i.e.,

    tox -e py27
    tox -e py36

Alternatively, you can run all tests in a single file via,

    tox -e <environment> -- tests/test_file.py

or for a specific test via,

    tox -e <environment> -- tests/test_file.py:TestClassName.test_method_name

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.

We use [Mocha](https://mochajs.org/), [Chai](http://chaijs.com/) and [Enzyme](http://airbnb.io/enzyme/) to test Javascript. Tests can be run with:

    cd /superset/superset/assets/javascripts
    npm i
    npm run test

## Linting

Lint the project with:

    # for python
    tox -e flake8

    # for javascript
    tox -e eslint

## API documentation

Generate the documentation with:

    pip install -r docs/requirements.txt
    python setup.py build_sphinx

## CSS Themes
As part of the npm build process, CSS for Superset is compiled from `Less`, a dynamic stylesheet language.

It's possible to customize or add your own theme to Superset, either by overriding CSS rules or preferably
by modifying the Less variables or files in `assets/stylesheets/less/`.

The `variables.less` and `bootswatch.less` files that ship with Superset are derived from
[Bootswatch](https://bootswatch.com) and thus extend Bootstrap. Modify variables in these files directly, or
swap them out entirely with the equivalent files from other Bootswatch (themes)[https://github.com/thomaspark/bootswatch.git]

## Translations

We use [Babel](http://babel.pocoo.org/en/latest/) to translate Superset. The
key is to instrument the strings that need translation using
`from flask_babel import lazy_gettext as _`. Once this is imported in
a module, all you have to do is to `_("Wrap your strings")` using the
underscore `_` "function".

We use `import {t, tn, TCT} from locales;` in js, JSX file, locales is in `./superset/assets/javascripts/` directory.

To enable changing language in your environment, you can simply add the
`LANGUAGES` parameter to your `superset_config.py`. Having more than one
options here will add a language selection dropdown on the right side of the
navigation bar.

    LANGUAGES = {
        'en': {'flag': 'us', 'name': 'English'},
        'fr': {'flag': 'fr', 'name': 'French'},
        'zh': {'flag': 'cn', 'name': 'Chinese'},
    }

As per the [Flask AppBuilder documentation] about translation, to create a
new language dictionary, run the following command (where `es` is replaced with
the language code for your target language):

    pybabel init -i superset/translations/messages.pot -d superset/translations -l es

Then it's a matter of running the statement below to gather all strings that
need translation

    fabmanager babel-extract --target superset/translations/ --output superset/translations/messages.pot --config superset/translations/babel.cfg -k _ -k __ -k t -k tn -k tct

You can then translate the strings gathered in files located under
`superset/translation`, where there's one per language. For the translations
to take effect, they need to be compiled using this command:

    fabmanager babel-compile --target superset/translations/

In the case of JS translation, we need to convert the PO file into a JSON file, and we need the global download of the npm package po2json.
We need to be compiled using this command:

    npm install po2json -g

Execute this command to convert the en PO file into a json file:

    po2json -d superset -f jed1.x superset/translations/en/LC_MESSAGES/messages.po superset/translations/en/LC_MESSAGES/messages.json

If you get errors running `po2json`, you might be running the ubuntu package with the same
name rather than the nodejs package (they have a different format for the arguments). You
need to be running the nodejs version, and so if there is a conflict you may need to point
directly at `/usr/local/bin/po2json` rather than just `po2json`.

## Adding new datasources

1. Create Models and Views for the datasource, add them under superset folder, like a new my_models.py
    with models for cluster, datasources, columns and metrics and my_views.py with clustermodelview
    and datasourcemodelview.

2. Create db migration files for the new models

3. Specify this variable to add the datasource model and from which module it is from in config.py:

    For example:

    `ADDITIONAL_MODULE_DS_MAP = {'superset.my_models': ['MyDatasource', 'MyOtherDatasource']}`

    This means it'll register MyDatasource and MyOtherDatasource in superset.my_models module in the source registry.

## Creating a new visualization type

Here's an example as a Github PR with comments that describe what the
different sections of the code do:
https://github.com/apache/incubator-superset/pull/3013

## Refresh documentation website

  Every once in a while we want to compile the documentation and publish it.
  Here's how to do it.

```
    # install doc dependencies
    pip install -r docs/requirements.txt

    # build the docs
    python setup.py build_sphinx

    # copy html files to temp folder
    cp -r docs/_build/html/ /tmp/tmp_superset_docs/

    # clone the docs repo
    cd ~/
    git clone https://git-wip-us.apache.org/repos/asf/incubator-superset-site.git

    # copy
    cp -r /tmp/tmp_superset_docs/ ~/incubator-superset-site.git/

    # commit and push to `asf-site` branch
    cd ~/incubator-superset-site.git/
    git checkout asf-site
    git add .
    git commit -a -m "New doc version"
    git push origin master
```

## Publishing a Pypi release

  We create a branch that goes along each minor release `0.24`
  and micro releases get corresponding tags as in `0.24.0`. Git history should
  never be altered in release branches.
  Bug fixes and security-related patches get cherry-picked
  (usually from master) as in `git cherry-pick -x {SHA}`.

  Following a set of cherries being picked, a release can be pushed to
  Pypi as follows:

```
    # branching off of master
    git checkout -b 0.25

    # cherry-picking a SHA
    git cherry-pick -x f9d85bd2e1fd9bc233d19c76bed09467522b968a
    # repeat with other SHAs, don't forget the -x

    # source of thruth for release numbers live in package.json
    vi superset/assets/package.json
    # hard code release in file, commit to the release branch
    git commit -a -m "0.25.0"

    # create the release tag in the release branch
    git tag 0.25.0
    git push apache 0.25 --tags

    # check travis to confirm the build succeeded as
    # you shouldn't assume that a clean cherry will be clean
    # when landing on a new sundae

    # compile the JS, and push to pypi
    # to run this part you'll need a pypi account and rights on the
    # superset package. Committers that want to ship releases
    # should have this access.
    # You'll also need a `.pypirc` as specified here:
    # http://peterdowns.com/posts/first-time-with-pypi.html
    ./pypi_push.sh

    # publish an update to the CHANGELOG.md for the right version range
    # looking the latest CHANGELOG entry for the second argument
    ./gen_changelog.sh 0.22.1 0.25.0
    # this will overwrite the CHANGELOG.md with only the version range
    # so you'll want to copy paste that on top of the previous CHANGELOG.md
    # open a PR against `master`
```

  In the future we'll start publishing release candidates for minor releases
  only, but typically not for micro release.
  The process will be similar to the process described above, expect the
  tags will be formatted `0.25.0rc1`, `0.25.0rc2`, ..., until consensus
  is reached.

  We should also have a Github PR label process to target the proper
  release, and tooling helping keeping track of all the cherries and
  target versions.

  For Apache releases, the process will be a bit heavier and should get
  documented here. There will be extra steps for signing the binaries,
  with a PGP key and providing MD5, Apache voting, as well as
  publishing to Apache's SVN repository. View the ASF docs for more
  information.


## Merging DB migrations

When 2 db migrations collide, you'll get an error message like this one:

```
  alembic.util.exc.CommandError: Multiple head revisions are present for
  given argument 'head'; please specify a specific target
  revision, '<branchname>@head' to narrow to a specific head,
  or 'heads' for all heads`
```

To fix it, first run `superset db heads`, this should list 2 or more
migration hashes. Then run
`superset db merge {PASTE_SHA1_HERE} {PASTE_SHA2_HERE}`. This will create
a new merge migration. You can then `superset db upgrade` to this new
checkpoint.