=============== Developer Guide =============== .. contents:: Table of Contents :local: .. _getting_started: Getting Started ======= Running a local copy of the client ---------------------------------- Running the client in developer mode from your local tree is a little different than running Certbot as a user. To get set up, clone our git repository by running: .. code-block:: shell git clone https://github.com/certbot/certbot If you're on macOS, we recommend you skip the rest of this section and instead run Certbot in Docker. You can find instructions for how to do this :ref:`here `. If you're running on Linux, you can run the following commands to install dependencies and set up a virtual environment where you can run Certbot. You only need to do this once. .. code-block:: shell cd certbot ./certbot-auto --os-packages-only ./tools/venv.sh Then in each shell where you're working on the client, do: .. code-block:: shell source ./venv/bin/activate After that, your shell will be using the virtual environment, and you run the client by typing: .. code-block:: shell certbot Activating a shell in this way makes it easier to run unit tests with ``tox`` and integration tests, as described below. To reverse this, you can type ``deactivate``. More information can be found in the `virtualenv docs`_. .. _`virtualenv docs`: https://virtualenv.pypa.io Find issues to work on ---------------------- You can find the open issues in the `github issue tracker`_. Comparatively easy ones are marked `Good Volunteer Task`_. If you're starting work on something, post a comment to let others know and seek feedback on your plan where appropriate. Once you've got a working branch, you can open a pull request. All changes in your pull request must have thorough unit test coverage, pass our tests, and be compliant with the :ref:`coding style `. .. _github issue tracker: https://github.com/certbot/certbot/issues .. _Good Volunteer Task: https://github.com/certbot/certbot/issues?q=is%3Aopen+is%3Aissue+label%3A%22Good+Volunteer+Task%22 .. _testing: Testing ------- When you are working in a file ``foo.py``, there should also be a file ``foo_test.py`` either in the same directory as ``foo.py`` or in the ``tests`` subdirectory (if there isn't, make one). While you are working on your code and tests, run ``python foo_test.py`` to run the relevant tests. For debugging, we recommend putting ``import ipdb; ipdb.set_trace()`` statements inside the source code. Once you are done with your code changes, and the tests in ``foo_test.py`` pass, run all of the unittests for Certbot with ``tox -e py27`` (this uses Python 2.7). Once all the unittests pass, check for sufficient test coverage using ``tox -e cover``, and then check for code style with ``tox -e lint`` (all files) or ``pylint --rcfile=.pylintrc path/to/file.py`` (single file at a time). Once all of the above is successful, you may run the full test suite, including integration tests, using ``tox``. We recommend running the commands above first, because running all tests with ``tox`` is very slow, and the large amount of ``tox`` output can make it hard to find specific failures when they happen. Also note that the full test suite will attempt to modify your system's Apache config if your user has sudo permissions, so it should not be run on a production Apache server. If you have trouble getting the full ``tox`` suite to run locally, it is generally sufficient to open a pull request and let Github and Travis run integration tests for you. .. _integration: Integration testing with the Boulder CA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To run integration tests locally, you need Docker and docker-compose installed and working. Fetch and start Boulder using: .. code-block:: shell ./tests/boulder-fetch.sh If you have problems with Docker, you may want to try `removing all containers and volumes`_ and making sure you have at least 1GB of memory. Run the integration tests using: .. code-block:: shell ./tests/boulder-integration.sh .. _removing all containers and volumes: https://www.digitalocean.com/community/tutorials/how-to-remove-docker-images-containers-and-volumes Code components and layout ========================== acme contains all protocol specific code certbot main client code certbot-apache and certbot-nginx client code to configure specific web servers certbot.egg-info configuration for packaging Certbot Plugin-architecture ------------------- Certbot has a plugin architecture to facilitate support for different webservers, other TLS servers, and operating systems. The interfaces available for plugins to implement are defined in `interfaces.py`_ and `plugins/common.py`_. The most common kind of plugin is a "Configurator", which is likely to implement the `~certbot.interfaces.IAuthenticator` and `~certbot.interfaces.IInstaller` interfaces (though some Configurators may implement just one of those). There are also `~certbot.interfaces.IDisplay` plugins, which implement bindings to alternative UI libraries. .. _interfaces.py: https://github.com/certbot/certbot/blob/master/certbot/interfaces.py .. _plugins/common.py: https://github.com/certbot/certbot/blob/master/certbot/plugins/common.py#L34 Authenticators -------------- Authenticators are plugins designed to prove that this client deserves a certificate for some domain name by solving challenges received from the ACME server. From the protocol, there are essentially two different types of challenges. Challenges that must be solved by individual plugins in order to satisfy domain validation (subclasses of `~.DVChallenge`, i.e. `~.challenges.TLSSNI01`, `~.challenges.HTTP01`, `~.challenges.DNS`) and continuity specific challenges (subclasses of `~.ContinuityChallenge`, i.e. `~.challenges.RecoveryToken`, `~.challenges.RecoveryContact`, `~.challenges.ProofOfPossession`). Continuity challenges are always handled by the `~.ContinuityAuthenticator`, while plugins are expected to handle `~.DVChallenge` types. Right now, we have two authenticator plugins, the `~.ApacheConfigurator` and the `~.StandaloneAuthenticator`. The Standalone and Apache authenticators only solve the `~.challenges.TLSSNI01` challenge currently. (You can set which challenges your authenticator can handle through the :meth:`~.IAuthenticator.get_chall_pref`. (FYI: We also have a partial implementation for a `~.DNSAuthenticator` in a separate branch). Installer --------- Installers plugins exist to actually setup the certificate in a server, possibly tweak the security configuration to make it more correct and secure (Fix some mixed content problems, turn on HSTS, redirect to HTTPS, etc). Installer plugins tell the main client about their abilities to do the latter via the :meth:`~.IInstaller.supported_enhancements` call. We currently have two Installers in the tree, the `~.ApacheConfigurator`. and the `~.NginxConfigurator`. External projects have made some progress toward support for IIS, Icecast and Plesk. Installers and Authenticators will oftentimes be the same class/object (because for instance both tasks can be performed by a webserver like nginx) though this is not always the case (the standalone plugin is an authenticator that listens on port 443, but it cannot install certs; a postfix plugin would be an installer but not an authenticator). Installers and Authenticators are kept separate because it should be possible to use the `~.StandaloneAuthenticator` (it sets up its own Python server to perform challenges) with a program that cannot solve challenges itself (Such as MTA installers). Installer Development --------------------- There are a few existing classes that may be beneficial while developing a new `~certbot.interfaces.IInstaller`. Installers aimed to reconfigure UNIX servers may use Augeas for configuration parsing and can inherit from `~.AugeasConfigurator` class to handle much of the interface. Installers that are unable to use Augeas may still find the `~.Reverter` class helpful in handling configuration checkpoints and rollback. Display ~~~~~~~ We currently only offer a "text" mode for displays. Display plugins implement the `~certbot.interfaces.IDisplay` interface. .. _dev-plugin: Writing your own plugin ======================= Certbot client supports dynamic discovery of plugins through the `setuptools entry points`_. This way you can, for example, create a custom implementation of `~certbot.interfaces.IAuthenticator` or the `~certbot.interfaces.IInstaller` without having to merge it with the core upstream source code. An example is provided in ``examples/plugins/`` directory. .. warning:: Please be aware though that as this client is still in a developer-preview stage, the API may undergo a few changes. If you believe the plugin will be beneficial to the community, please consider submitting a pull request to the repo and we will update it with any necessary API changes. .. _`setuptools entry points`: http://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points .. _coding-style: Coding style ============ Please: 1. **Be consistent with the rest of the code**. 2. Read `PEP 8 - Style Guide for Python Code`_. 3. Follow the `Google Python Style Guide`_, with the exception that we use `Sphinx-style`_ documentation:: def foo(arg): """Short description. :param int arg: Some number. :returns: Argument :rtype: int """ return arg 4. Remember to use ``pylint``. .. _Google Python Style Guide: https://google.github.io/styleguide/pyguide.html .. _Sphinx-style: http://sphinx-doc.org/ .. _PEP 8 - Style Guide for Python Code: https://www.python.org/dev/peps/pep-0008 Submitting a pull request ========================= Steps: 1. Write your code! 2. Make sure your environment is set up properly and that you're in your virtualenv. You can do this by running ``./tools/venv.sh``. (this is a **very important** step) 3. Run ``tox -e lint`` to check for pylint errors. Fix any errors. 4. Run ``tox --skip-missing-interpreters`` to run the entire test suite including coverage. The ``--skip-missing-interpreters`` argument ignores missing versions of Python needed for running the tests. Fix any errors. 5. If your code touches communication with an ACME server/Boulder, you should run the integration tests, see `integration`_. 6. Submit the PR. 7. Did your tests pass on Travis? If they didn't, fix any errors. Updating certbot-auto and letsencrypt-auto ========================================== Updating the scripts -------------------- Developers should *not* modify the ``certbot-auto`` and ``letsencrypt-auto`` files in the root directory of the repository. Rather, modify the ``letsencrypt-auto.template`` and associated platform-specific shell scripts in the ``letsencrypt-auto-source`` and ``letsencrypt-auto-source/pieces/bootstrappers`` directory, respectively. Building letsencrypt-auto-source/letsencrypt-auto ------------------------------------------------- Once changes to any of the aforementioned files have been made, the ``letsencrypt-auto-source/letsencrypt-auto`` script should be updated. In lieu of manually updating this script, run the build script, which lives at ``letsencrypt-auto-source/build.py``: .. code-block:: shell python letsencrypt-auto-source/build.py Running ``build.py`` will update the ``letsencrypt-auto-source/letsencrypt-auto`` script. Note that the ``certbot-auto`` and ``letsencrypt-auto`` scripts in the root directory of the repository will remain **unchanged** after this script is run. Your changes will be propagated to these files during the next release of Certbot. Opening a PR ------------ When opening a PR, ensure that the following files are committed: 1. ``letsencrypt-auto-source/letsencrypt-auto.template`` and ``letsencrypt-auto-source/pieces/bootstrappers/*`` 2. ``letsencrypt-auto-source/letsencrypt-auto`` (generated by ``build.py``) It might also be a good idea to double check that **no** changes were inadvertently made to the ``certbot-auto`` or ``letsencrypt-auto`` scripts in the root of the repository. These scripts will be updated by the core developers during the next release. Updating the documentation ========================== In order to generate the Sphinx documentation, run the following commands: .. code-block:: shell make -C docs clean html man This should generate documentation in the ``docs/_build/html`` directory. .. _docker: Running the client with Docker ============================== You can use Docker Compose to quickly set up an environment for running and testing Certbot. This is especially useful for macOS users. To install Docker Compose, follow the instructions at https://docs.docker.com/compose/install/. .. note:: Linux users can simply run ``pip install docker-compose`` to get Docker Compose after installing Docker Engine and activating your shell as described in the :ref:`Getting Started ` section. Now you can develop on your host machine, but run Certbot and test your changes in Docker. When using ``docker-compose`` make sure you are inside your clone of the Certbot repository. As an example, you can run the following command to check for linting errors:: docker-compose run --rm --service-ports development bash -c 'tox -e lint' You can also leave a terminal open running a shell in the Docker container and modify Certbot code in another window. The Certbot repo on your host machine is mounted inside of the container so any changes you make immediately take effect. To do this, run:: docker-compose run --rm --service-ports development bash Now running the check for linting errors described above is as easy as:: tox -e lint .. _prerequisites: Notes on OS dependencies ======================== OS-level dependencies can be installed like so: .. code-block:: shell letsencrypt-auto-source/letsencrypt-auto --os-packages-only In general... * ``sudo`` is required as a suggested way of running privileged process * `Python`_ 2.6/2.7 is required * `Augeas`_ is required for the Python bindings * ``virtualenv`` and ``pip`` are used for managing other python library dependencies .. _Python: https://wiki.python.org/moin/BeginnersGuide/Download .. _Augeas: http://augeas.net/ .. _Virtualenv: https://virtualenv.pypa.io Debian ------ For squeeze you will need to: - Use ``virtualenv --no-site-packages -p python`` instead of ``-p python2``. FreeBSD ------- Package installation for FreeBSD uses ``pkg``, not ports. FreeBSD by default uses ``tcsh``. In order to activate virtualenv (see below), you will need a compatible shell, e.g. ``pkg install bash && bash``.