appups.sh

Rebar downgrade instruction generation.

app="myapp"

function gen-ups {
    rebar generate-appups previous_release=$1
    cat $app/lib/*/ebin/*.appup
}

# This uses a dirty bunch of hacks to "generate" downgrade instructions
# (upgrade instructions in the opposite direction) with the current rebar
# version.
function main {
    cp -r $app appup.$app.backup
    rm -r $app/lib/*/ebin/*.appup
    echo -e "\n    UPGRADES:\n"
    gen-ups $1
    echo -e "\n    DOWNGRADES:\n"
    mv $app $app.appup.tmp
    cp -r $1 $app
    rm -r $app/lib/*/ebin/*.appup
    gen-ups $app.appup.tmp
    # get files into original state
    rm -rf $app $app.appup.tmp
    mv appup.$app.backup $app
}

main ${1:?"Usage: appups <prev_release_dir>"}