Request: `singularity` dependency for detecing that singularity-based planners can run

[hectorpal]

Context

• Some users might want to use planutils in Docker but with no privileged access
• Right now, only a few packages works, including VAL and pyperplan

Definition of done

• Installing "singularity" package check if singularity planners can run, reporting the need for privileged access
• Installing planners that use singularity would fail right away if
• Documentation specifies that singularity is needed for most plans, and that installing them fails quickly

Implementation idea

• “singularity” install pulls a tiny singularity image and attempt to run it
• first installation attempt use some bandwidth
• new calls would be faster because image is in singularity cache

Checklist

• Should check to see if it's installed and has the right version/privileges required to run the planners that need it.
• Warn the user (fail to install) if it's not setup right
• Planners that use singularity should have this package as a dependency

[hectorpal]

This might lead to a different issue.

Following the discussion at #85
What if we had a dependency for "compile" that can only be installed when creating the docker image?

For instance,

• "compile" install the ubuntu packages added so MACQ compiles.
• Then we ask MACQ to have such dependency.

Alternative:

• Recommend people to package binaries outside and provide a base Dockerfile for that. That's basically a Dockerfile including the current Docker and adding some packages as suggestion.

[haz]

Not sure I follow the suggestions...I think this suggestion is more useful now that installing singularity is easier on modern systems. No longer requires Go and rebuilding the entire project.

[hectorpal]

I tried to make it more clear

[haz]

You mean for this issue? I think having singularity is now a very real possibility for average users on modern Ubuntu OS'. So having this as a package makes sense. We wouldn't need to "compile" singularity to get it going anymore.