What is FRE?

FRE, the FMS Runtime Environment, is the companion runtime workflow for FMS-based climate and earth system models, and contains scripts and batch job handlers to compile models, run experiments, and postprocess and analyze the output. Developed around 2004 by GFDL’s Modeling System Division, FRE was developed primarily in one repository (“fre-commands”, https://github.com/NOAA-GFDL/FRE), used subtools in another repository (FRE-NCtools, https://github.com/NOAA-GFDL/fre-nctools), and was deployed using a set of Environment Modules (https://gitlab.gfdl.noaa.gov/fre/modulefiles). Originally, the major releases of FRE were rivers (Arkansas, Bronx) and the minor releases were numbers. In practice, though, the “Bronx” release name was retained and the number has been incremented over the years. e.g. Bronx-23 is the latest release.

Over the last couple years, MSD’s workflow team has reengineered the compiling and postprocessing parts of FRE, in a modern python and Cylc-based ecosystem (running experiments is not yet possible with this new FRE; stay tuned). Following a semantic versioning adopted in other FMS repositories, the reengineered FRE is versioned with a year and incrementing two-digit number. e.g. the first release of 2024 is 2024.01, the second 2024.02, and the first release next year will be 2025.01. (Optional minor releases are also available in the scheme; e.g. 2024.01.01 would be the first minor/patch release after 2024.01.) This version is used as tags in FRE repositories and in the corresponding conda (and in the future, container) release, and can be retrieved from fre --version.

fre-cli (this repository) can be considered a successor to the FRE Bronx “fre-commands” repository, which primarily contains user-facing tools and subtools. fre-workflows (https://github.com/NOAA-GFDL/fre-workflows) is a companion repository containing workflow definitions that can be run by the Cylc workflow engine. It contains workflow-specific elements previously in FRE Bronx, and allows flexibility to support multiple and more complex workflows. The two new FRE repositories are versioned with the same approach, and updates will be released together for some time to ensure compatibility.

The “cli” in fre-cli derives from the shell “fre SUBCOMMAND COMMAND” structure inspired by git, cylc, and other modern Linux command-line tools. This enables discovery of the tooling capability, useful for complex tools with multiple options. e.g. fre --help, fre make --help, fre pp --help.

Underneath, fre-cli is python, and the workflows and tooling can be run through a Jupyter notebook, or through other python scripts. fre-cli is conda-installable from the “noaa-gfdl” channel (conda install --channel noaa-gfdl fre-cli).