diff options
| -rwxr-xr-x | make-snapshot | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/make-snapshot b/make-snapshot new file mode 100755 index 0000000..d677c40 --- /dev/null +++ b/make-snapshot @@ -0,0 +1,75 @@ +#! /bin/sh +# +# make-snapshot {source-directory} {snapshot-directory} +# +set -euf + +source="$1" +snapshot="$2" + +echo "source directory is $source" +echo "snapshot directory is $snapshot" + +# TODO check whether $snapshot is a snapshot directory +ls "$snapshot/by-date" >/dev/null + +# Set $link_dest to the latest snapshot, if there is one. +# pre: +# $snapshot/by-date is a directory that contains only directories +# where names are produced by $(date +%Y-%d-%mT%H:%M:%S) or +# start with a . (and thus are not listed by ls). +# post: +# $link_dest is set iff there is a latest snapshot +# $link_dest is set to the filename of the latest snapshot +# 2012-11-08 tv TODO check pre-condition +latest="$(ls -r "$snapshot/by-date" | grep ^[0-9] | head -n 1)" +if test -n "$latest"; then + link_dest="$snapshot/by-date/$latest" + echo latest snapshot is $link_dest +fi + +timestamp="$(date +%Y-%m-%dT%H:%M:%S)" +complete="$snapshot/by-date/$timestamp" +partial="$snapshot/by-date/.$timestamp.part" + +# TODO incooperate into ach's version +if present_partials="$(ls -ar "$snapshot/by-date" | grep '^\..*\.part$')"; then +case $(echo "$present_partials" | wc -l) in + (0) : ;; # nothing to do + (1) + echo "found partial snapshot: $present_partials" + printf "do you want to continue [y/N] " + read answer + case "$answer" in + (y|Y) partial="$snapshot/by-date/$present_partials";; + (*) + echo "abort"; exit 23 + ;; + esac + ;; + (*) + echo "found too many partial snapshots:" + echo "$present_partials" + echo "abort"; exit 23 + ;; +esac +fi + +# sync $source to $partial +if test -d "${link_dest-}"; then + cp -al "$link_dest" "$partial" +fi +rsync -v \ + -aAXF \ + --delete \ + "$source/" "$partial" +sync + +mv "$partial" "$complete" +sync + +# mark this snapshot as current +rm -f "$snapshot/current" +ln -snf "by-date/$timestamp" "$snapshot/current" + +echo "current snapshot is $(find "$snapshot/current" -exec readlink -f \{\} \;)" |