use JSON config file instead of arguments

1 files changed, 48 insertions, 12 deletions

diff --git a/go.sh b/go.sh
index 4a9ff6f..ec15e82 100755
--- a/go.sh
+++ b/go.sh
@@ -1,20 +1,56 @@
 #!/bin/bash
+
+read_config()
+{
+        eval config="($(jq -r '. | to_entries | .[] | "[\"" + .key + "\"]=" + (.value | @sh)'))"
+}
+
+check_dependencies()
+{
+        for c in flock jq mountpoint btrfs pv
+        do
+                command -v $c >/dev/null
+        done
+}
+
+check_user_is_root()
+{
+        [ "$UID" = 0 ]
+}
+
 set -e
-wd=/root/src/local-btrfs-backup
-src=/
-dst=/srv/sdm1/borges
-parent_file=$wd/last-parent.txt
+check_dependencies
+check_user_is_root
+
+if [ $# != 1 ]
+then
+        echo "Usage: $0 <config.json>" >&2
+        exit 1
+fi
+
+[ -r "$1" ]
+exec 3<>"$1"
+flock -n 3
+declare -A config
+read_config <&3
 
-snapshot="${src%/}"/backup~$(date -Ins)
+src=${config[source]}
+dst=${config[destination]}
+head=${config[head]}
+new_snapshot=${src%/}/.snapshot~$(date -Ins)
 
-set -x
-if [ -e "$parent_file" ]
+mountpoint -q "$src"
+if [ "$head" ]
 then
-        read parent < "$parent_file"
+        read parent_snapshot < "$head"
+        mountpoint -q "$parent_snapshot"
+else
+        parent_snapshot=
 fi
+mkdir -p "$dst"
 
-btrfs subvolume snapshot -r "$src" "$snapshot"
-btrfs send "$snapshot" ${parent:+ -p "$parent"} | pv | btrfs receive "$dst"
-printf "%s\n" "$snapshot" > "$parent_file"~tmp
-mv -T -- "$parent_file"~tmp "$parent_file"
+btrfs subvolume snapshot -r "$src" "$new_snapshot"
+btrfs send "$new_snapshot" ${parent_snapshot:+ -p "$parent_snapshot"} | pv | btrfs receive "$dst"
+printf "%s\n" "$new_snapshot" > "$head"~tmp
+mv -T -- "$head"~tmp "$head"