support custom retention policies

1 files changed, 26 insertions, 7 deletions

diff --git a/backomp b/backomp
index 0a73a2f..1517ef5 100755
--- a/backomp
+++ b/backomp
@@ -2,9 +2,17 @@
 
 set -e
 
+# FIXME: clean up repetition
 ! read -rd '' FILTER_AWK <<'EOF'
 function flr(n, s) { return int(n / s) * s }
 
+BEGIN {
+	if (match(retain, /([*0-9]+)h/, md)) hr = md[1]
+	if (match(retain, /([*0-9]+)d/, md)) dr = md[1]
+	if (match(retain, /([*0-9]+)w/, md)) wr = md[1]
+	if (match(retain, /([*0-9]+)m/, md)) mr = md[1]
+}
+
 {
 	t = mktime(gensub(/(.*\/|^)(.+)-(..)-(..)-(..)(..)(..)/,
 		"\\2 \\3 \\4 \\5 \\6 \\7", 1), 1)
@@ -15,10 +23,10 @@ function flr(n, s) { return int(n / s) * s }
 	w = m + flr(t - m, 7*24*60*60)
 }
 
-h in hkeep || hc++ < 24 { hkeep[h] = $1 }
-d in dkeep || dc++ < 7 { dkeep[d] = $1 }
-w in wkeep || wc++ < 4 { wkeep[w] = $1 }
-{ mkeep[m] = $1 }
+h in hkeep || hr == "*" || hc++ < hr { hkeep[h] = $1 }
+d in dkeep || dr == "*" || dc++ < dr { dkeep[d] = $1 }
+w in wkeep || wr == "*" || wc++ < wr { wkeep[w] = $1 }
+m in mkeep || mr == "*" || mc++ < mr { mkeep[m] = $1 }
 
 END {
 	for (i in hkeep) keep[hkeep[i]]++
@@ -39,9 +47,10 @@ run() {
 backup() {
 	dest_dir="${1}"
 	src_path="${2}"
+	retain="${3:-"*h*d*w*m"}"
 
 	[[ "$((dcount++))" -ne 0 ]] && echo
-	echo "[${dcount}] ${src_path} => ${dest_dir}"
+	echo "[${dcount}] [${retain}] ${src_path} => ${dest_dir}"
 	mapfile -t snaps < <(shopt -s nullglob;
 		printf '%s\n' "${dest_dir}/"* | sort -r | head -c -1)
 
@@ -51,7 +60,8 @@ backup() {
 	snaps=("${dest_path}" "${snaps[@]}")
 
 	mapfile -t keep < <(
-		awk "${FILTER_AWK}" < <(printf '%s\n' "${snaps[@]}"))
+		awk -v "retain=${retain}" "${FILTER_AWK}" < <(
+			printf '%s\n' "${snaps[@]}"))
 	if [[ -z "${keep}" ]]; then
 		echo "WARNING: dirs to keep shouldn't be empty; skipping" >&2
 		return
@@ -73,8 +83,17 @@ while IFS='=' read -r f1 f2; do
 
 	if [[ "${f1}" =~ ^\[(.*)]$ ]]; then
 		base_path="${BASH_REMATCH[1]}"
+		retain=
+		continue
+	fi
+
+	if [[ "${f1}" == '$'* ]]; then
+		if [[ "${f1}" == '$retain' ]]; then
+			retain="${f2}"
+		fi
+
 		continue
 	fi
 
-	backup "${base_path}/${f1}" "${f2}"
+	backup "${base_path}/${f1}" "${f2}" "${retain}"
 done < "${1}"