#!/bin/bash

# Note: this is only an example of how you'd call create-filelist.  Edit to fit
# your requirements.

# Takes a list of module names.  Generates file lists for all of them and them
# moves them into place at once.  If you are creating hardlinks between rsync
# modules, it is required that you update the file lists of both mirrors at the
# same time.  Otherwise the clients may make separate copies of the files.

mods=$*

if [[ -z $mods ]]; then
    echo "usage: $0 <module> [<module> ...]"
    exit 2
fi

CREATE=/usr/local/bin/create-filelist

# A single lockfile for everything we're modifying
LOCKFILE=.lock.create-filelist

# The directory where all of the modules live
TOPD=/srv/pub

# These strings will be eval'ed later with $mod replaced by its value in
# context.
FILELIST=fullfilelist
TIMELIST='fullfiletimelist-$mod'

(
    # We want to wait forever until we can do what we're asked
    flock -x 9

    # If you don't want to wait forever, try one of the following:
    # flock -n 9 || exit 1      - Gives up immediately
    # flock -w 120 9 || exit 1  - Waits 120 seconds and then gives up
    # Don't change the '9', unless you change the last line of this script.

    tmpd=$(mktemp -d -t create-filelist.XXXXXXXXXX)
    trap "rm -rf $tmpd" EXIT
    cd $tmpd

    # Create all of the filelists
    for mod in $mods; do
        $CREATE -c -s -d $TOPD/$mod-f fl-$mod -t tl-$mod
    done

    # Now diff the file lists and delete the ones which didn't change
    for mod in $mods; do
        currentfl=$TOPD/$mod/${FILELIST/'$mod'/$mod}
        currenttl=$TOPD/$mod/${TIMELIST/'$mod'/$mod}

        # If a file list exsts and doesn't differ from what we just generated,
        # delete the latter.
        if [[ -f $currentfl ]] && diff -q fl-$mod $currentfl > /dev/null; then
            rm -f $fl
        fi
        if [[ -f $currenttl ]] && diff -q tl-$mod $currenttl > /dev/null; then
            rm -f $fl
        fi
    done

    # And finally, move all of the files which need updating into place
    for mod in $mods; do
        currentfl=$TOPD/$mod/${FILELIST/'$mod'/$mod}
        currenttl=$TOPD/$mod/${TIMELIST/'$mod'/$mod}

        if [[ -f fl-$mod ]]; then
            chmod 644 fl-$mod
            cp -p fl-$mod $currentfl
        fi
        if [[ -f tl-$mod ]]; then
            chmod 644 tl-$mod
            cp -p tl-$mod $currenttl
        fi
    done

) 9>$LOCKFILE