Environments¶

The IGWN Conda Distribution includes a number of environments, covering different versions of Python, and testing, staging, and stable package lists. You can use these environments either directly from the CVMFS (see Using pre-built environments with CVMFS), or by installing them manually after downloading the relevant YAML files (you can find download links on the details page for each environment).

Default environments¶

There are three Default Environments which are recommended for most users:

igwn¶

The igwn environment represents the latest stable set of packages and versions that have been approved for use by the IGWN Software Change Control Board.

This environment is recommended for 'everyday' use and will only change when a new release is tagged and announced.

Production IGWN analyses should use a Tagged environment from CVMFS

To improve the reproducibility of results, all IGWN production analyses using the IGWN Conda Distribution in CVMFS should use a Tagged environment that is fixed on creation.

The igwn environment in CVMFS is a symbolic link to a tagged environment, where the link is updated whenever a new release is created. To unwrap the current igwn environment to get the tagged environment that it is linked to, you can use readlink, for example:

$ conda activate igwn
$ echo ${CONDA_PREFIX}
/cvmfs/software.igwn.org/conda/envs/igwn
$ readlink -f "${CONDA_PREFIX}"
/cvmfs/software.igwn.org/conda/envs/igwn-py39-20220317

In this example all production analyses should explicitly use the igwn-py39-20220317 environment.

igwn-staging¶

The igwn-staging environment represents the latest set of packages that have been approved for inclusion in a future stable environment.

Staging environments are subject to continuous change

The staging environments can and will change from day-to-day as more packages are approved by the SCCB, so no production analyses should rely upon them.

igwn-testing¶

The igwn-testing environment includes the latest packages that have been requested for inclusion in a future stable environment via an SCCB request.

Testing environments are subject to continuous change

The testing environments can and will change from day-to-day as more packages are approved by the SCCB, so no production analyses should rely upon them.

Versioned environments¶

The Default environments above track a specific versioned environment which is pinned to a minor release of Python (mainly for technical reasons). As such the Default environments will periodically upgrade from one minor Python version to the next to keep up-to-date.

To allow users to pin their workflow to a specific Python version, Versioned environments are available that will always use the same version of Python:

Tagged environments¶

Both the Default and Versioned environments described above will periodically change to reflect requests to and approvals by the IGWN SCCB. The IGWN Conda Distribution in CVMFS provides Tagged environments that are fixed on creation and will never change.

The environments are named using the Python minor version and a date tag reflecting when they were created, using the YYYYMMDD.MICRO CalVer versioning scheme. For example an environment built with Python 3.9 on January 1st 2022 would be named

igwn-py39-20220101

Recommended for production analysis

Given their fixed contents, the tagged environments are recommended for production analysis that need to be reproducible.

Supported Python versions¶

The IGWN Conda Distribution roughly follows the NEP 29 schedule for supporting minor Python versions, with the additional requirement that each Python version is fully supported by conda-forge (the relevant migration has been completed and that version is part of the conda-forge pinned packages). This means that:

IGWN Conda Distribution Python version support

IGWN Conda Distribution environments will be supported for all minor versions of (C)Python released within the 42 months prior to the Distribution release date that are also supported by conda-forge, and at minimum the two latest minor versions supported by conda-forge.

Making changes¶

See Change control for details on how the package lists are managed, and how to request or propose changes.