Contributing

Please sign one of the contributor license agreements below.
File an issue to notify the maintainers about what you're working on.
Fork the repo, develop and test your code changes, add docs.
Make sure that your commit messages clearly describe the changes.
Send a pull request.

Here are some guidelines for hacking on oauth2client.

Before writing code, file an issue

Use the issue tracker to start the discussion. It is possible that someone else is already working on your idea, your approach is not quite right, or that the functionality exists already. The ticket you file in the issue tracker will be used to hash that all out.

Fork `oauth2client`

We will use GitHub's mechanism for forking repositories and making pull requests. Fork the repository, and make your changes in the forked repository.

Include tests

Be sure to add the relevant tests before making the pull request. Docs will be updated automatically when we merge to master, but you should also build the docs yourself via tox -e docs and make sure they're readable.

Make the pull request

Once you have made all your changes, tests, and updated the documentation, make a pull request to move everything back into the main oauth2client repository. Be sure to reference the original issue in the pull request. Expect some back-and-forth with regards to style and compliance of these rules.

Using a Development Checkout

You’ll have to create a development environment to hack on oauth2client, using a Git checkout:

While logged into your GitHub account, navigate to the oauth2client repo on GitHub.
Fork and clone the oauth2client repository to your GitHub account by clicking the "Fork" button.

Clone your fork of oauth2client from your GitHub account to your local computer, substituting your account username and specifying the destination as hack-on-oauth2client. For example:

$ cd ${HOME}
$ git clone git@github.com:USERNAME/oauth2client.git hack-on-oauth2client
$ cd hack-on-oauth2client
$ # Configure remotes such that you can pull changes from the oauth2client
$ # repository into your local repository.
$ git remote add upstream https://github.com:google/oauth2client
$ # fetch and merge changes from upstream into master
$ git fetch upstream
$ git merge upstream/master

Now your local repo is set up such that you will push changes to your GitHub repo, from which you can submit a pull request.

Create a virtualenv in which to install oauth2client:
```
$ cd ~/hack-on-oauth2client
$ virtualenv -ppython2.7 env
```
Note that very old versions of virtualenv (virtualenv versions below, say, 1.10 or thereabouts) require you to pass a --no-site-packages flag to get a completely isolated environment.
You can choose which Python version you want to use by passing a -p flag to virtualenv. For example, virtualenv -ppython2.7 chooses the Python 2.7 interpreter to be installed.
From here on in within these instructions, the ~/hack-on-oauth2client/env virtual environment you created above will be referred to as $VENV. To use the instructions in the steps that follow literally, use the export VENV=~/hack-on-oauth2client/env command.
Install oauth2client from the checkout into the virtualenv using setup.py develop. Running setup.py develop must be done while the current working directory is the oauth2client checkout directory:
```
$ cd ~/hack-on-oauth2client
$ $VENV/bin/python setup.py develop
```

Running Tests

To run all tests for oauth2client on a single Python version, run nosetests from your development virtualenv (See Using a Development Checkout above).
To run the full set of oauth2client tests on all platforms, install tox into a system Python. The tox console script will be installed into the scripts location for that Python. While in the oauth2client checkout root directory (it contains tox.ini), invoke the tox console script. This will read the tox.ini file and execute the tests on multiple Python versions and platforms; while it runs, it creates a virtualenv for each version/platform combination. For example:
```
$ sudo pip install tox
$ cd ~/hack-on-oauth2client
$ tox
```
In order to run the pypy environment (in tox) you'll need at least version 2.6 of pypy installed. See the docs for more information.
Note that django related tests are turned off for Python 2.6 and 3.3. This is because django dropped support for 2.6 in django==1.7 and for 3.3 in django==1.9.

Running System Tests

To run system tests you can execute:
```
$ tox -e system-tests
$ tox -e system-tests3
```
This alone will not run the tests. You'll need to change some local auth settings and download some service account configuration files from your project to run all the tests.
System tests will be run against an actual project and so you'll need to provide some environment variables to facilitate this.
- OAUTH2CLIENT_TEST_JSON_KEY_PATH: The path to a service account JSON key file; see tests/data/gcloud/application_default_credentials.json as an example. Such a file can be downloaded directly from the developer's console by clicking "Generate new JSON key". See private key docs for more details.
- OAUTH2CLIENT_TEST_P12_KEY_PATH: The path to a service account P12/PKCS12 key file. You can download this in the same way as a JSON key, just select "P12 Key" as your "Key type" when downloading.
- OAUTH2CLIENT_TEST_P12_KEY_EMAIL: The service account email corresponding to the P12/PKCS12 key file.
- OAUTH2CLIENT_TEST_USER_KEY_PATH: The path to a JSON key file for a user. If this is not set, the file created by running gcloud auth login will be used. See tests/data/gcloud/application_default_credentials_authorized_user.json for an example.
- OAUTH2CLIENT_TEST_USER_KEY_EMAIL: The user account email corresponding to the user JSON key file.
Examples of these can be found in scripts/local_test_setup.sample. We recommend copying this to scripts/local_test_setup, editing the values and sourcing them into your environment:
```
$ source scripts/local_test_setup
```

Contributor License Agreements

Before we can accept your pull requests you'll need to sign a Contributor License Agreement (CLA):

If you are an individual writing original source code and you own the intellectual property, then you'll need to sign an individual CLA.
If you work for a company that wants to allow you to contribute your work, then you'll need to sign a corporate CLA.

You can sign these electronically (just scroll to the bottom). After that, we'll be able to accept your pull requests.