catch-fail - trap failure and sleep so as to enter a melange build for dbug

README.md

catch-fail - trap and sleep to enter a melange build for debug

Usage: catch-fail op

   catch-fail is used to help debug a melange build.  In a 'run' section
   you can add at the top:

      eval $(/home/build/catch-fail eval-trap 1h)

   And then if the section fails it will block for 1 hour so that
   from the outside you can run

      catch-fail enter

catch-fail

#!/bin/sh
# vi: ts=4 expandtab
# https://gist.github.com/smoser/84909431c72e6409251c8897ac816872
Usage() {
    local me=${0#**/}
    cat <<EOF
Usage: $me op

   This is tested with bubblewrap (bwrap) backend.
   It will need adjusting for docker or other backend.
   The setgid and setuid values probably need changing on other system.

   $me is used to help debug a melange build.  In a 'run' section
   you can add at the top:

      eval \$(/home/build/catch-fail eval-trap 1h)

   And then if the section fails it will block for 1 hour so that
   from the outside you can run

      $me enter
EOF
}

case "$1" in
    enter)
        p=$(ps axww | awk '/CATCH-FAIL/ { print $1; exit; }');
        ( [ -n "$p" ] || { echo "no pid found"; exit 1; };
        echo pid=$p; sudo nsenter -a --setgid 1002 --setuid 1001 -t $p /bin/sh )
        ;;
    eval-trap)
        p='rc=$?; [ $rc -eq 0 ] || '\"$0\"' CATCH-FAIL '\"${2:-30m}\"' $rc'
        echo trap "'$p'" EXIT
        ;;
    -h|--help)
        Usage
        exit
        ;;
    CATCH-FAIL)
        nap=${2:-30m}
        rc=${3:-"-1"}
        sleep ${nap} &
        pid=$!
        echo "============ section failed with rc $rc ==============="
        echo "============ sleeping for $nap in $pid  ================"
        echo "I am: $(id)"
        echo "I had $# args: $*"
        wait $pid
        ;;
    *) Usage 1>&2;
       exit 1;;
esac