Infrastructure Guide

This guide serves as an advanced version of the contributing documentation and contains the information on how we manage MetPy and the infrastructure behind it.

Versioning

To manage identifying the version of the code, MetPy relies upon setuptools_scm. setuptools_scm takes the current version of the source from git tags and any additional commits. For development, the version will have a string like 0.10.0.post209+gff2e549f.d20190918, which comes from git describe. This version means that the current code is 209 commits past the 0.10.0 tag, on git hash ff2e549f, with local changes on top, last made on a date (indicated by d20190918). For a release, or non-git repo source dir, the version will just come from the most recent tag (i.e. v0.10.0).

To make a new version, simply add a new tag with a name like vMajor.Minor.Bugfix and push to GitHub. Github will add a new release with a source archive.zip file. Running

python setup.py sdist

will build a new source distribution with the appropriately generated version file as well. This will also create a new stable set of documentation.

Documentation

MetPy’s documentation is built using sphinx >= 2.1. API documentation is automatically generated from docstrings, written using the NumPy docstring standard. There are also example scripts in the examples directory. Using the sphinx-gallery extension, these examples are executed and turned into a gallery of thumbnails. The extension also makes these scripts available as Jupyter notebooks.

The documentation is hosted on GitHub Pages. The docs are built automatically from master with every build on Travis-CI; every merged PR will have the built docs upload to GitHub Pages. As part of the build, the documentation is also checked with doc8. To see what the docs will look like, you also need to install the sphinx-rtd-theme package.

Other Tools

Continuous integration is performed by Travis CI and AppVeyor. Travis runs the unit tests on Linux for all supported versions of Python, as well as runs against the minimum package versions. flake8 (with the pep8-naming and flake8-quotes plugins) is also run against the code to check formatting. Travis is also used to build the documentation and to run the examples to ensure they stay working. AppVeyor is a similar service; here the tests and examples are run against Python 2 and 3 for both 32- and 64-bit versions of Windows.

Test coverage is monitored by codecov.io.

The following services are used to track code quality:

Releasing

To create a new release, go to the GitHub page and make a new release. The tag should be a sensible version number, like v1.0.0. Add a name (can just be the version) and add some release notes on what the big changes are. It’s also possible to use loghub to get information on all the issues and PRs that were closed for the relevant milestone.

PyPI

Once the new release is published on GitHub, this will create the tag, which will trigger new builds on Travis (and AppVeyor, but that’s not relevant). When the main test build on Travis (currently Python 3 tests) succeeds, Travis will handle building the source distribution and wheels, and upload them to PyPI.

To build and upload manually (if for some reason it is necessary):

  1. Do a pull locally to grab the new tag. This will ensure that setuptools_scm will give you the proper version.

  2. (optional) Perform a git clean -f -x -d from the root of the repository. This will delete everything not tracked by git, but will also ensure clean source distribution. MANIFEST.in is set to include/exclude mostly correctly, but could miss some things.

  3. Run python setup.py sdist bdist_wheel (this requires that wheel is installed).

  4. Upload using twine: twine upload dist/*, assuming the dist/ directory contains only files for this release. This upload process will include any changes to the README as well as any updated flags from setup.py.

Conda

MetPy conda packages are automatically produced and uploaded to Anaconda.org thanks to conda-forge. Once the release is built and uploaded to PyPI, then a Pull Request should be made against the MetPy feedstock, which contains the recipe for building MetPy’s conda packages. The Pull Request should:

  1. Update the version

  2. Update the hash to match that of the new source distribution uploaded to PyPI

  3. Reset the build number to 0 (if necessary)

  4. Update the dependencies (and their versions) as necessary

The Pull Request will test building the packages on all the platforms. Once this succeeds, the Pull Request can be merged, which will trigger the final build and upload of the packages to anaconda.org.