Usage

Beside singularity-permanent-cache, also spc is added to PATH as a short-hand when installing the package. singularity-permanent-cache is also available as a stand-alone script singularity_permanent_cache.py.

singularity-permant-cache has no dependencies and only requires a modern python version (3.5 or higher).

usage: singularity-permanent-cache [-h] [-d CACHE_DIR] [-s SINGULARITY_EXE]
                               [--which-cache] [-v] [-q]
                               <IMAGE>

Creates a permanent cache on disk for singularity images. Returns the location
of the image in the cache. WARNING: This program will never check if a newer
image is available. Make sure unique tags or hashes are used!

positional arguments:
  <IMAGE>               The singularity URI to the image. For example:
                        'docker://debian:buster-slim'

optional arguments:
  -h, --help            show this help message and exit
  -d CACHE_DIR, --cache-dir CACHE_DIR
                        Path to the cache location. Uses the
                        SINGULARITY_PERMANENTCACHEDIR, or SINGULARITY_CACHEDIR
                        environment variable by default.
  -s SINGULARITY_EXE, --singularity-exe SINGULARITY_EXE
                        Path to singularity executable.
  --which-cache         Show which cache the program will use and exit.
  -v, --verbose         Increase log verbosity. Can be used multiple times.
  -q, --quiet           Decrease log verbosity. Can be used multiple times.

Acknowledgements

Lots of thanks to @TMiguelT, @illusional and @vsoch for their constructive feedback on this PR for Cromwell which led to the development of this program.

The filelock implementation is based on py-filelock. Huge thanks to @benediktschmitt & contributors for this filelock example which they made Public Domain.