Development

Branches

Code contributions should start on a feature branch derived from the dev branch. Pull requests will then be merged into the dev branch. When a new major or minor version of micromamba is released, then the dev branch will be updated to build the new version and dev will be be merged into the main branch. This ensures that the image behavior remains constant for each minor version of micromamba.

The following types of changes are allowed to bypass the dev branch and have their pull requests go straight to the main branch:

  • bumping versions of existing base images

  • removing a base image that is no longer supported

  • documentation enhancements

  • testing changes

  • security updates

While documentation enhancements can bypass the dev branch, documentation for new features should be committed to dev along with the code for the feature.

Testing

Testing Dependencies

  • docker

  • nox

  • GNU parallel (optional)

  • apptainer (optional)

  • pre-commit (optional)

Setup

The Bats testing framework is used to test the micromamba docker images and derived images. When cloning this repo you’ll want to use git clone --recurse-submodules ..., which will bring in the git sub-modules for Bats.

Pre-commit should be enabled after cloning the repo by executing pre-commit install in the root of the repo.

Nox is used to automate tests and must be installed separately.

Executing Tests

To execute the test suite on all base images, run nox in the top-level directory of the repo. To execute the test suite on a single base image, run nox --session "tests(base_image='debian:12-slim')".

If GNU parallel is available on the $PATH, then the test suite will be run in parallel using all logical CPU cores available.

Tests requiring apptainer will automatically be skipped if apptainer is not found on the $PATH.

Road map

Community members are welcomed and encouraged to propose development work that supports their needs.

The image maintainers are currently working on or planning to work on:

  1. Better supporting conda environment activation when using apptainer/singularity

  2. Improved caching during our image builds such that image digests only are modified by pull requests that alter the image. Documentation changes should not result in new image digests.

Policies

  1. No additional programs or packages are installed into the parent images except for those required by micromamba, our helper scripts, and glibc (as conda packges generally have a dependency on glibc). We aim to keep our images small and limit our dependencies.

  2. Entrypoint script should not write to files in the home directory. On some container execution systems, such as appatainer, the host home directory is automatically mounted and we don’t want to mess up or pollute the home directory on the host system.

  3. We do not update any packages within the parent images (ie, we do not apt-get update or similar).