should be able to run pkg(1) from a backup boot environment without editing it

[jclulow]

While working around omniosorg/omnios-build#3770, I mounted the backup boot environment created as part of pkg update -v pkg so that I could get the previous copy of the libraries there. In order to convince it to work, I ended up having to copy the pkg entrypoint script itself into /tmp and edit it:

• I had to comment out the call to pkg.site_paths.init()
• I had to remove the -E argument in the interpreter line

Once I did that, I was able to set PYTHONPATH in the environment and use the program:

gerrit0 # PYTHONPATH=/tmp/tmp.FjayTS/usr/lib/pkg/python3.11:/tmp/tmp.FjayTS/usr/lib/python3.11:/tmp/tmp.FjayTS/usr/lib/python3.11/lib-dynload /tmp/pkg list -v expat
FMRI                                                                         IFO
pkg://omnios/library/[email protected]:20230428T103651Z                   i--

It seems like it would be relatively easy to augment the site_paths module to be able to recognise when it's running inside a boot environment and enable the operator to use it without modification?

[citrus-it]

Generally I use this, which works, but we should be able to make this easier - perhaps even having a flag in pkg that helps.

BEROOT=/tmp/tmp.FjayTS
LD_LIBRARY_PATH=$BEROOT/usr/lib/amd64 \
    PYTHONPATH=$BEROOT/usr/lib/pkg/python3.11:$BEROOT/usr/lib/python3.11/vendor-packages \
    $BEROOT/usr/bin/python3.11 $BEROOT/usr/bin/pkg list -u

[jclulow]

Ah, that's clever (using python3.11 directly)!