:description: How to hack on Deis including setup instructions .. _hacking: Hacking on Deis =============== We try to make it simple to hack on Deis. However, there are necessarily several moving pieces and some setup required. We welcome any suggestions for automating or simplifying this process. If you're just getting into the Deis codebase, look for GitHub issues with the label `easy-fix`_. These are more straightforward or low-risk issues and are a great way to become more familiar with Deis. Prerequisites ------------- You can develop on any supported platform including your laptop, cloud providers or on bare metal. We strongly recommend a minimum 3-node cluster. The development workflow requires a Docker Registry that is accessible to you (the developer) and to all of the hosts in your cluster. You will also need a `deisctl`_ client to update images and restart components. Fork the Repository ------------------- To get Deis running for development, first `fork the Deis repository`_, then clone your fork of the repository: .. code-block:: console $ git clone git@github.com:/deis.git $ cd deis $ export DEIS_DIR=`pwd` # to use in future commands Install the Client ------------------ In a development environment you'll want to use the latest version of the client. Install its dependencies by using the Makefile and symlinking ``client/deis.py`` to ``deis`` on your local workstation. .. code-block:: console $ cd $DEIS_DIR/client $ make install $ sudo ln -fs $DEIS_DIR/client/deis.py /usr/local/bin/deis $ deis Usage: deis [...] Configure SSH Tunneling ----------------------- To connect to the cluster using ``deisctl``, you must add the private key to ``ssh-agent``. For example, when using Vagrant: .. code-block:: console $ ssh-add ~/.vagrant.d/insecure_private_key Set ``DEISCTL_TUNNEL`` so the ``deisctl`` client on your workstation can connect to one of the hosts in your cluster: .. code-block:: console $ export DEISCTL_TUNNEL=172.17.8.100 Test connectivity using ``deisctl list``: .. code-block:: console $ deisctl list Configure a Docker Registry --------------------------- The development workflow requires Docker Registry set at the ``DEV_REGISTRY`` environment variable. If you're developing locally you can use the ``dev-registry`` target to spin up a quick, disposable registry inside a Docker container. .. code-block:: console $ make dev-registry To configure the registry for local Deis development: export DEV_REGISTRY=192.168.59.103:5000 If you are developing elsewhere, you must setup the registry yourself. Make sure it meets the following requirements: #. You can push Docker images from your workstation #. Hosts in the cluster can pull images with the same URL Development Workflow -------------------- Deis includes ``Makefile`` targets designed to simplify the development workflow. This workflow is typically: #. Update source code and commit your changes using ``git`` #. Use ``make -C build`` to build a new Docker image #. Use ``make -C dev-release`` to push a snapshot release #. Use ``make -C restart`` to restart the component This can be shortened to a one-liner using the ``deploy`` target: .. code-block:: console $ make -C controller deploy You can also use the same tasks on the root ``Makefile`` to operate on all components at once. For example, ``make deploy`` will build, dev-release, and restart all components on the cluster. .. important:: In order to cut a dev-release, you must commit changes using ``git`` to increment the SHA used when tagging Docker images Test Your Changes ----------------- Deis ships with a comprehensive suite of automated tests, most written in Go. You can find instructions for `running the tests`_ under the ``tests/`` directory. Useful Commands --------------- Once your controller is running, here are some helpful commands. Tail Logs ````````` .. code-block:: console $ deisctl journal controller Rebuild Services from Source ```````````````````````````` .. code-block:: console $ make -C controller build push restart Restart Services ```````````````` .. code-block:: console $ make -C controller restart Django Shell ```````````` .. code-block:: console $ deisctl ssh controller # SSH into the controller $ nse deis-controller # inject yourself into the container $ cd /app # change into the django project root $ ./manage.py shell # get a django shell Have commands other Deis developers might find useful? Send us a PR! Standards & Test Coverage ------------------------- When changing Python code in the Deis project, keep in mind our :ref:`standards`. Specifically, when you change local code, you must run ``make flake8 && make coverage``, then check the HTML report to see that test coverage has improved as a result of your changes and new unit tests. .. code-block:: console $ make flake8 flake8 ./api/models.py:17:1: F401 'Group' imported but unused ./api/models.py:81:1: F841 local variable 'result' is assigned to but never used make: *** [flake8] Error 1 $ $ make coverage coverage run manage.py test --noinput api web WARNING Cannot synchronize with etcd cluster Creating test database for alias 'default'... ............................................... ---------------------------------------------------------------------- Ran 47 tests in 47.768s OK Destroying test database for alias 'default'... coverage html $ head -n 25 htmlcov/index.html | grep pc_cov 81% Pull Requests ------------- Please create a GitHub `pull request`_ for any code changes that will benefit Deis users in general. This workflow helps changesets map well to discrete features. Creating a pull request on the Deis repository also runs an integration test on http://ci.deis.io to ensure the pull request doesn't break any tests or reduce code coverage. .. _`easy-fix`: https://github.com/deis/deis/issues?labels=easy-fix&state=open .. _`deisctl`: https://github.com/deis/deis/deisctl .. _`fork the Deis repository`: https://github.com/deis/deis/fork .. _`running the tests`: https://github.com/deis/deis/tree/master/tests#readme .. _`pull request`: https://github.com/deis/deis/pulls