Add a guide about publishing dists via GH Actions

Resolves pypa/gh-action-pypi-publish#2

source/guides/index.rst

@@ -29,3 +29,4 @@ introduction to packaging, see :doc:`/tutorials/index`.
    migrating-to-pypi-org
    using-testpypi
    making-a-pypi-friendly-readme
+   publishing-package-distribution-releases-using-github-actions-ci-cd-workflows

source/guides/publishing-package-distribution-releases-using-github-actions-ci-cd-workflows.rst

@@ -0,0 +1,168 @@
+Publishing Package Distribution 📦 Releases Using GitHub Actions CI/CD Workflows 🤖
+===================================================================================
+
+`GitHub Actions CI/CD`_ allow you to run a series of commands
+whenever an event occurs in the GitHub Platform. One of the
+popular choices is having a workflow that's triggered by a
+``push`` event.
+This guide will show you how to publish a Python distribution
+package whenever a tagged commit is pushed.
+
+.. attention::
+
+   This guide *assumes* that you already have a project that
+   you know how to build dists for and *it lives on GitHub*.
+
+.. warning::
+
+   At the time of writing this guide, `GitHub Actions CI/CD`_
+   is still in public beta. If you don't have it enabled,
+   you should join the waitlist in order to gain the access.
+
+   N.B. It is known that GitHub is going to make Actions
+   publicly available on the Nov 13th, 2019.
+
+
+Saving credentials on GitHub
+----------------------------
+
+In this guide, we'll demonstrate uploading to both production
+PyPI and Test PyPI meaning that we'll have two separate sets
+of creds. And we'll need to save them in GitHub repo settings.
+
+Let's begin! 🚀
+
+1. Go to https://pypi.org/manage/account/#api-tokens and
+   create a new `API token`_. If you have the project on PyPI
+   already, please limit the token scope to just that project.
+   You can call it smth like
+   ``GitHub Actions CI/CD — project-org/project-repo``
+   in order for it to be easily distinguishable in the token
+   list.
+   **Don't close the page just yet — you won't see that token
+   again.**
+2. In a separate browser tab or window, go to the ``Settings``
+   tab of your target repository and then click on `Secrets`_
+   in the left sidebar.
+3. Create a new secret called ``pypi_password`` and copy-paste
+   the token from the fist step.
+4. Now, go to https://test.pypi.org/manage/account/#api-tokens
+   and repeat the steps. Save that Test PyPI token on GitHub
+   as ``test_pypi_password``.
+
+
+Creating a workflow definition
+------------------------------
+
+GitHub CI/CD Workflows are declared in YAML files stored under
+``.github/`` of your repository.
+
+Start it with a meaningful name and define the even that
+should make GitHub run this workflow:
+
+.. code-block:: yaml
+
+   name: Publish Python 🐛 distribution package 📦 to PyPIs
+
+   on: push
+
+
+Defining a workflow job environment
+-----------------------------------
+
+Now, let's add initial setup for our job. It's a process that
+will execute commands that we'll define later.
+In this guide, we'll choose to use Ubuntu 18.04:
+
+.. code-block:: yaml
+
+   build-n-publish:
+     name: Build and publish Python 🐛 dist 📦 to PyPIs
+     runs-on: ubuntu-18.04
+
+
+Checking out the project and building dists
+-------------------------------------------
+
+Then, add the following under the ``build-n-publish`` section:
+
+.. code-block:: yaml
+
+     steps:
+     - uses: actions/checkout@master
+     - name: Set up Python 3.7
+       uses: actions/setup-python@v1
+       with:
+         version: 3.7
+
+This will download your repository into the CI runner and then
+install and activate Python 3.7.
+
+And now we can build dists from source. In this example, we'll
+use ``pep517`` package, *assuming that your project has a ``pyproject.toml`` properly set up (see :pep:`517`/:pep:`518`)*.
+
+.. tip::
+
+   You can use any other method for building dists as long as
+   it produces ready-to-upload artifacts saved into ``dist/``
+   folder.
+
+So add this to the steps list:
+
+.. code-block:: yaml
+
+     - name: Install pep517
+       run: >-
+         python -m
+         pip install
+         pep517
+         --user
+     - name: Build a binary wheel and a source tarball
+       run: >-
+         python -m
+         pep517.build
+         --source
+         --binary
+         --out-dir dist/
+         .
+
+
+Publishing dist to Test PyPI and production PyPI
+------------------------------------------------
+
+Finally, add the following steps in the end:
+
+.. code-block:: yaml
+
+     - name: Publish 📦 to Test PyPI
+       uses: pypa/gh-action-pypi-publish@master
+       with:
+         password: ${{ secrets.test_pypi_password }}
+         repository_url: https://test.pypi.org/legacy/
+     - name: Publish 📦 to production PyPI
+       if: startsWith(github.event.ref, 'refs/tags')
+       uses: pypa/gh-action-pypi-publish@master
+       with:
+         password: ${{ secrets.pypi_password }}
+
+These two steps use `pypa/gh-action-pypi-publish`_ GitHub
+Action: the first one uploads contents of the `dist/` folder
+into Test PyPI unconditionally and the second does that to
+production PyPI but only if the current commit is tagged.
+
+
+That's all, folks!
+------------------
+
+Now, whenever you push a tagged commit to your Git repo remote
+on GitHub, this workflow will publish it to PyPI.
+And it'll publish any push to Test PyPI which is useful for
+providing test builds to your alpha users as well as making
+sure that your release pipeline keeps being healthy! 
+
+
+.. _API token: https://pypi.org/help/#apitoken
+.. _GitHub Actions CI/CD: https://github.com/features/actions
+.. _pypa/gh-action-pypi-publish:
+.. _Secrets:
+   https://help.github.com/en/articles/virtual-environments-for-github-actions#creating-and-using-secrets-encrypted-variables