backup: write backups to backups/ and rotate (keep 7), gitignore backups/

.gitignore

@@ -41,3 +41,6 @@ mongo-volume
 
 # backup files created by backup.sh
 mongo-volume-backup-*.tar.gz
+
+# backups directory for mongo-volume tarballs
+/backups/

backup.sh

@@ -1,8 +1,33 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# scale down mongo service while we copy its volume
 docker service scale utility-bills-tracker_mongo=0
 
+# timestamp for filename
 TIMESTAMP=$(date +"%Y-%m-%d-%H-%M")
-BACKUP_FILE="mongo-volume-backup-$TIMESTAMP.tar.gz"
+
+# backup directory and retention (can be overridden via env)
+BACKUP_DIR="${BACKUP_DIR:-backups}"
+KEEP="${KEEP:-7}"
+
+mkdir -p "$BACKUP_DIR"
+
+BACKUP_FILE="$BACKUP_DIR/mongo-volume-backup-$TIMESTAMP.tar.gz"
 
 sudo tar -czvpf "$BACKUP_FILE" mongo-volume
 
+# rotate old backups: keep only the newest $KEEP files
+if [ "$KEEP" -gt 0 ]; then
+  # gather files sorted newest-first
+  mapfile -t files < <(ls -1t "$BACKUP_DIR"/mongo-volume-backup-*.tar.gz 2>/dev/null || true)
+  if [ "${#files[@]}" -gt "$KEEP" ]; then
+    for f in "${files[@]:$KEEP}"; do
+      echo "Removing old backup: $f"
+      rm -f -- "$f"
+    done
+  fi
+fi
+
+# bring mongo service back up
 docker service scale utility-bills-tracker_mongo=1