only hold onto backups for 14 days (not 31) and show when the backups will be...

only hold onto backups for 14 days (not 31) and show when the backups will be deleted in the control panel

management/backup.py

@@ -14,8 +14,9 @@ import dateutil.parser, dateutil.relativedelta, dateutil.tz
 
 from utils import exclusive_process, load_environment, shell
 
-# settings
-keep_backups_for = "31D" # destroy backups older than 31 days except the most recent full backup
+# destroy backups when the most recent increment in the chain
+# that depends on it is this many days old.
+keep_backups_for_days = 14
 
 def backup_status(env):
 	# What is the current status of backups?
@@ -24,8 +25,8 @@ def backup_status(env):
 	# see how large the storage is.
 
 	now = datetime.datetime.now(dateutil.tz.tzlocal())
-	def reldate(date):
-		rd = dateutil.relativedelta.relativedelta(now, date)
+	def reldate(date, ref):
+		rd = dateutil.relativedelta.relativedelta(ref, date)
 		if rd.days >= 7: return "%d days" % rd.days
 		if rd.days > 1: return "%d days, %d hours" % (rd.days, rd.hours)
 		if rd.days == 1: return "%d day, %d hours" % (rd.days, rd.hours)
@@ -44,7 +45,7 @@ def backup_status(env):
 			backups[key] = {
 				"date": m.group("date"),
 				"date_str": date.strftime("%x %X"),
-				"date_delta": reldate(date),
+				"date_delta": reldate(date, now),
 				"full": m.group("incbase") is None,
 				"previous": m.group("incbase"),
 				"size": 0,
@@ -59,9 +60,27 @@ def backup_status(env):
 			backups[key]["encsize"] += os.path.getsize(encfn)
 
 	# Ensure the rows are sorted reverse chronologically.
-	# This is relied on by should_force_full().
+	# This is relied on by should_force_full() and the next step.
 	backups = sorted(backups.values(), key = lambda b : b["date"], reverse=True)
 
+	# When will a backup be deleted?
+	saw_full = False
+	deleted_in = None
+	days_ago = now - datetime.timedelta(days=keep_backups_for_days)
+	for bak in backups:
+		if deleted_in:
+			# Subsequent backups are deleted when the most recent increment
+			# in the chain would be deleted.
+			bak["deleted_in"] = deleted_in
+		if bak["full"]:
+			# Reset when we get to a full backup. A new chain start next.
+			saw_full = True
+			deleted_in = None
+		elif saw_full and not deleted_in:
+			# Mark deleted_in only on the first increment after a full backup.
+			deleted_in = reldate(days_ago, dateutil.parser.parse(bak["date"]))
+			bak["deleted_in"] = deleted_in
+
 	return {
 		"directory": basedir,
 		"encpwfile": os.path.join(env['STORAGE_ROOT'], 'backup/secret_key.txt'),
@@ -135,7 +154,7 @@ def perform_backup(full_backup):
 	shell('check_call', [
 		"/usr/bin/duplicity",
 		"remove-older-than",
-		keep_backups_for,
+		"%dD" % keep_backups_for_days,
 		"--archive-dir", "/tmp/duplicity-archive-dir",
 		"--name", "mailinabox",
 		"--force",

management/templates/system-backup.html

 <style>
+#backup-status th { text-align: center; }
 #backup-status tr.full-backup td { font-weight: bold; }
 </style>
 
@@ -19,6 +20,7 @@
     <th colspan="2">When</th>
     <th>Type</th>
     <th>Size</th>
+    <th>Deleted in...</th>
   </thead>
   <tbody>
   </tbody>
@@ -56,8 +58,12 @@ function show_system_backup() {
         if (b.full) tr.addClass("full-backup");
         tr.append( $('<td/>').text(b.date_str + " " + r.tz) );
         tr.append( $('<td/>').text(b.date_delta + " ago") );
-        tr.append( $('<td/>').text(b.full ? "full" : "incremental") );
+        tr.append( $('<td/>').text(b.full ? "full" : "increment") );
         tr.append( $('<td style="text-align: right"/>').text( nice_size(b.encsize)) );
+        if (b.deleted_in)
+          tr.append( $('<td/>').text(b.deleted_in) );
+        else
+          tr.append( $('<td class="text-muted">n/a</td>') );
         $('#backup-status tbody').append(tr);
 
         total_disk_size += b.size;