Background:

• Note: LArSoft is designed to be run by experiments, so it is not possible to set up LArSoft without setting up LArSoft for a specific experiment. You do this via the setup guide for your experiment.(https://larsoft.github.io/LArSoftWiki/Quick_Links)
• The core LArSoft code lives in a set of git repositories maintained by the LArSoft core team. Can view the code organization at http://larsoft.org/larsoft-code-organization/
• If you do not have code changes to LArSoft code itself, you may just set up the appropriate products and a Fermilab Hierarchical Configuration Language (FHiCL) file, ends in .fcl

To set up and run LArSoft, the user:

1. Runs a setup script
   a) Source <experiment specific script>
   b) This tells UPS where to find the programs needed like UPS itself, git, MRB, ROOT, and LArSoft. A UPS product is a software package set up and distributed via UPS, Unix Product Support. Each UPS product is entirely self-contained, aside from dependencies.
   c) Specific example for SBND:
   i) using CVMFS: source/cvmfs/sbnd.opensciencegrid.org/products/sbnd/setup_sbnd.sh
   ii) using a local UPS database /path/to/products filled with pullProducts:
   source /path/to/products/setup
   export MRB_PROJECT=larsoft
   setup mrb
   Specific example for DUNE:
   source /grid/fermiapp/products/dune/setup_dune.sh
   Can find links to all LArSoft Collaboration experiments at: https://larsoft.github.io/LArSoftWiki/Quick_Links
2. Creates a new development area. This creates a number of subdirectories.
   mkdir <working_dir> #Do not use your home directory, as the libraries you build can get large.
   cd <working_dir>
   mrb newDev or mrb n
   # May need to specific the version and qualified unless larsoft product is set up.
   mrb newDev -v <version> -q <qualifiers>
   # Can find out the larsoft releases
   ups list -aK+ larsoft
   # May want to just make the products area (checks that src, build are already there)
   mrb newDev -p
   Can see mrb newDev options at: https://cdcvs.fnal.gov/redmine/projects/mrb/wiki/MrbRefereceGuide#newDev-n
3. Sets up a LArSoft release – Can be Integration or Production.
   setup larsoft vXXX -q e15:<prof|debug>
4. Sets up local products
   source localProducts_larsoft_vxx_xx_xx_ex_prof/setup
5. Checks out code from repository
   cd $MRB_SOURCE
   mrb gitCheckout <code>
   This will get the code from current development head. If you want code with a different version of LArSoft, use -t with mrb g
   mrb g -t LARSOFT_SUITE_vxx_xx_xx <code>
   mrb g larsoft_suite
   mrb g larsoftAlg_suite
6. Builds and tests the code, all commands must be run in the same shell.
   cd $MRB_BUILDDIR
   mrbsetenv  #set up development environment
   mrb b (build) -jN #N is number of parallel build streams
   mrb z (zapBuild) #to get rid of what you just built
   mrbsetenv
   mrb t (test) [jN]  #run buildtool with test, all commands must be run in the same shell
   May need to fix code, rebuild, retest.
7. Once the code works as expected, publish it to a feature branch.

A simple view

1. mkdir my_larsoft
2. source <experiment_setup_script>
3. cd my_larsoft/
4. mrb newDev -vvxx_xx_xx -q <e15:debug>
5. source localProducts_larsoft_vxx_xx_xx_ex_prof/setup
6. cd $MRB_SOURCE
7. mrb g larsoft_suite
8. mrb g larsoftAlg_suite
9. cd $MRB_BUILDDIR
10. mrbsetenv
11. mrb b -jN
12. mrb t -jN