Pynng Developer Notes

A list of notes, useful only to developers of the library, and not for users.

Testing without pulling dependencies from GitHub

It can lower feedback speed dramatically when testing pynng, and needing to clone nng and mbedtls from GitHub. If you are just doing this one time, it is not terrible, but when you’re working on how pynng is built it is tedious and painful to wait for a slow internet connection. This can be mitigated by cloning nng and mbedtls outside of this repository, running a git server, and pointing the setup.cfg script to

# clone *once* locally
git clone https://github.com/nanomsg/nng ~/pynng-deps/nanomsg/nng
git clone https://github.com/Mbed-TLS/mbedtls ~/pynng-deps/Mbed-TLS/mbedtls
# start a git daemon in the parent directory
git daemon --reuseaddr --base-path="$HOME/pynng-deps" --export-all

Then change the setup.cfg to point to the local git server. Change the repo lines from repo=https://github.com/nanomsg/nng to repo=git://127.0.0.1:/nanomsg/nng. The relevant sections of the file will look like this:

[build_nng]
repo=git://127.0.0.1:/nanomsg/nng

[build_mbedtls]
repo=git://127.0.0.1:/Mbed-TLS/mbedtls

Testing CI changes

When testing CI changes, it can be painful, embarrassing, and tedious, to push changes just to see how CI does. Sometimes this is necessary, for example for architectures or operating systems you do not own so cannot test on. However, you can test CI somewhat using the incredible nektos/act tool. It enables running Github Actions locally. We do need to pass some flags to make the tool do what we want.

If you have single failing tests, you can narrow down the build by setting specific cibuildwheel options in the pyproject.toml file, to skip certain Python versions or architectures.

Running CI Locally

Use this command to run Github Actions locally using the nektos/act tool

# run cibuildwheel, using ubuntu-20.04 image
# This is how  you test on Linux
# Needs --container-options='-u root' so cibuildwheel can launch its own docker containers
act --container-options='-u root' \
    -W .github/workflows/cibuildwheel.yml \
    --matrix os:ubuntu-20.04 \
    --pull=false \
    --artifact-server-path=artifacts

--pull=false prevents downloading the latest runner docker image. --artifact-server-path=artifacts enables an artifact server, and lets you look at the built artifacts afterwards.

Making a new release

We use setuptools_scm to properly version the project, and GitHub Actions to build wheels.

  1. Tag the commit locally, and push

    git tag vx.y.z -m "Release version x.y.z."
git push --tags

  2. Navigate to the job through GitHub

  3. Download the artifacts, and unzip them all to a directory pynng-x.y.z

  4. Use twine to push all the artifacts

    twine upload -r pypi pynng-x.y.z/*