add quota warnings

templates/90-quota.conf.j2

@@ -109,4 +109,20 @@ service quota-status {
   }
   client_limit = 1
 }
+
+plugin {
+  quota_warning = storage=10%% quota-warning 10 %u
+  quota_warning2 = storage=80%% quota-warning 80 %u
+}
+
+service quota-warning {
+  executable = script /usr/local/bin/quota-warning.sh
+  # use some unprivileged user for executing the quota warnings
+  user = vmail
+  unix_listener quota-warning {
+    user = vmail
+    group = vmail
+  }
+}
+
 {% endif %}