[master] Setting up preinstalled DIRAC in a pilot

[atsareg]

This PR allows to specify the setup script location which will be used to define a preinstalled DIRAC environment instead of installing DIRACOS2/DIRAC from scratch on a worker node. Example script locations:

• /cvmfs/dirac.egi.eu/dirac/pro/diracos/diracosrc
• /cvmfs/dirac.egi.eu/dirac/bashrc_egi

This is addressing #166 but makes use of predefined DIRAC clients in CVMFS.

[fstagni]

This is a bit different/simpler solution to #166 , the question here if this would be enough.
Using a venv, as suggested in the original issue, would add flexibility on top of what is here.

[atsareg]

Indeed. But this one solves the immediate issue. The solution based on venv needs some experimenting, at least from me. Also I am worried to have too many nested environments coexistence.

[chrisburr]

This effectively bypasses the pilot version specified in the CS which doesn't feel great. It also doesn't work if you have multiple architectures. If we could instead have a layout like:

/cvmfs/dirac.egi.eu/dirac/{version}/{uname -m}-{uname -s}/diracosrc

You can then have --preinstalledEnvPrefix=/cvmfs/dirac.egi.eu/dirac/ and would probably be good enough to replace the LHCbInstallDIRAC pilot command.

[atsareg]

In CVMFS we have now /cvmfs/dirac.egi.eu/dirac/{version}/diracos/diracosrc. So a particular DIRAC version can be specified. But not different platforms. I will see how the specified version can be taken from a standard option

[chrisburr]

I'd propose having --preinstalledEnvBashrc= in addition to --preinstalledEnvPrefix=/cvmfs/dirac.egi.eu/dirac/ with the view that it contains at least something like:

source ${DIRACOS}/diracosrc

The value of DIRACOS would be set externally using --preinstalledEnvPrefix

[atsareg]

The PR is updated along the lines of the discussion above. I keep two settings, --preinstalledEnv and --preinstalledEnvPrefix. If --preinstalledEnv is specified, it is used as the environment setting script, --preinstalledEnvPrefix is ignored in that case. If --preinstalledEnvPrefix is specified (and not --preinstalledEnv), then environment is resolved with the release area structure like in the CVMFS of LHCb. I have updated the /cvmfs/dirac.egi.eu to this structure already

[fstagni]

One more note: the case of user-defined environments is not considered in this implementation.

[fstagni]

Closing as superseded by #205