Git Hook

hiera-update-git.sh

#!/bin/bash
#
# Hook suitable for maintaining hiera directories.
#

# --- Command line
refname="$1"
oldrev="$2"
newrev="$3"

# --- Safety check
if [ -z "$GIT_DIR" ]; then
    echo "Don't run this script from the command line." >&2
    echo " (if you want, you could supply GIT_DIR then run" >&2
    echo "  $0 <ref> <oldrev> <newrev>)" >&2
    exit 1
fi

if [ -z "$refname" -o -z "$oldrev" -o -z "$newrev" ]; then
    echo "Usage: $0 <ref> <oldrev> <newrev>" >&2
    exit 1
fi

# --- Check types
# if $newrev is 0000...0000, it's a commit to delete a ref.
zero="0000000000000000000000000000000000000000"

if [ "$newrev" = "$zero" ]; then
    newrev_type=delete
else
    newrev_type=$(git cat-file -t $newrev)
fi

checkout_directory="/tmp/checkout_directory"
checkout_lock="/tmp/checkout_directory/.lock"
blobs_directory="${checkout_directory}/blobs"

function build_path() {
    branch="$1"

    case "$branch" in
        hiera/*/*)
            hiera_name=${branch##hiera/}
            echo "${checkout_directory}/hiera/${hiera_name}"
            ;;
        *)
            echo "${checkout_directory}/branch/${branch}"
            ;;
    esac
}

function main() {
    case "$refname","$newrev_type" in
        refs/tags/*,commit) ;;
        refs/tags/*,delete) ;;
        refs/tags/*,tag) ;;
        refs/remotes/*,commit) ;;
        refs/remotes/*,delete) ;;
        refs/heads/*,commit)
            branch=${refname##refs/heads/}
            link=$(build_path "$branch")
            link_directory=$(dirname "$link")
            blob_name=$(base64 <<< "$branch")
            checkout="${blobs_directory}/${blob_name}"

            mkdir -p "$link_directory"
            mkdir -p "$checkout"

            echo "creating blob: $checkout"
            GIT_WORK_TREE=$checkout git checkout --force --quiet $newrev

            echo "creating link: $link -> $checkout"
            ln -nsf "$checkout" "$link"
            ;;
        refs/heads/*,delete)
            branch=${refname##refs/heads/}
            link=$(build_path "$branch")

            if [[ -L "$link" ]]; then
                blob_path=$(readlink "$link")
                echo "removing blob: $blob_path"
                rm -rf "$blob_path"
            fi

            echo "removing link: $link"
            rm -f "$link"

            link_directory=$(dirname "$link")
            while rmdir "$link_directory" 2> /dev/null; do
                echo "removed directory: $link_directory"
                link_directory=$(dirname "$link_directory")
            done
            ;;
        *)
            # Anything else (is there anything else?)
            echo "*** Update hook: unknown type of update to ref $refname of type $newrev_type" >&2
            return 1
            ;;
    esac

    return 0
}

(
    flock -e 200
    main
    exit $?
) 200> $checkout_lock

exit $?