Spack package repository for Muon Collider software stack

This repository holds a set of Spack recipes for Muon Collider software (under namespace mucoll) based on Key4hep stack. It extends the corresponding key4hep-stack repository, which is required for installation, overriding several packages by the ones customised for Muon Collider simulation studies.

After installing Spack and downloading the key4hep-spack and mucoll-spack repositories, the whole software stack can be installed using the following commands:

# Add repositories
spack repo add ./key4hep-spack
spack repo add ./mucoll-spack

# Create a Spack environment
spack env create sim
spack env activate sim

# Copy package configurations
cp ./mucoll-spack/environments/mucoll-release/*.yaml $SPACK_ENV/

# Install the software stack
spack add mucoll-stack
spack concretize --reuse
spack install --fail-fast

# Load the Muon Collider environment
source $MUCOLL_STACK

Setting up the environment

When signing in to a machine with the installed sofware stack (VM or Docker container), it has to be loaded into the environment:

spack env activate sim
source $MUCOLL_STACK

Package versioning

Preferred convention for version names in Spack is numbers separated by dots, without leading zeros, e.g. 1.2.13. Conversion to tag names in mucoll packages is provided by MCIlcsoftpackage class defined in packages/mucoll-stack/mucoll_utils.py, e.g. for lcgeo package version 0.17 corresponds to tag name v00-17-MC.

Adding new versions for individual packages

After a new tag for the package is created, e.g. v00-17-MC in lcgeo repository, it can be added to this Spack repository in two steps:

1. Get the archive checksum for the new tag

spack checksum lcgeo 0.17
# Validates archive URL and returns the checksum
    version('0.17', sha256='5ab33aaf5bc37deba82c2dde78cdce6c0041257222ed7ea052ecdd388a41cf9b')

2. Add the returned version definition to the corresponding package file: packages/lcgeo/package.py

NOTE: This repository only contains packages maintained by the Muon Collider collaboration. If the version of interest is missing from Spack for some other package, the line with a new version definition should be added to the package file in the corresponding repository.
To see locations of other repositories: spack repo list

Creating a new stack release

To introduce a new release version for the whole software stack, update the version number in packages/mucoll-stack/package.py and then update versions of all the relevant packages in [environments/mucoll-release/packages.yaml].
Test this new configuration in a fresh environment:

# Create a development environment
spack env create dev
spack env activate dev

# Copy the package configuration
cp ./mucoll-spack/environments/mucoll-release/*.yaml $SPACK_ENV/

# Add stack with updated version to the environment
spack add mucoll-stack

# Check which packages would be installed
spack spec --reuse -NIt

Packages that are already installed in the sim environment are known to Spack and will be reused, providing a clear indication of which part of the dependency tree will be modified by the new release.