Add new max_last_will_delay value and change default

THANKS

@@ -22,6 +22,7 @@ Mariano Guerra
 Szymon Kałasz
 Christoph Krey
 Michael Kuehne
+Will Lisac (@wlisac)
 Chiradip Mandal
 Chris Nesbitt-Smith
 Andrei Nesterov

apps/vmq_server/priv/vmq_server.schema

@@ -199,23 +199,32 @@
  end}.
 
 %% @doc The maximum delay for a last will message. This setting
-%% applies only to MQTTv5 sessions and overrides the value provided by
-%% the client.
-%% The delay should be an integer followed by one of 's', 'h' 'd',
-%% 'w', 'm', 'y' for day, week, month, and year.
+%% applies only to MQTTv5 sessions and can be used to override the
+%% value provided by the client.
+
+%% The delay can be either 'client' which means the value specified by
+%% the client is used, or an integer followed by one of 's', 'h' 'd',
+%% 'w', 'm', 'y' for day, week, month, and year used to cap the value
+%% provided by the client..
 {mapping, "max_last_will_delay", "vmq_server.max_last_will_delay", [
- {default, "0s"},
- {commented, "0s"},
+ {default, "client"},
+ {commented, "client"},
  {datatype, string}
  ]}.
 
 {translation, "vmq_server.max_last_will_delay",
  fun(Conf) ->
  S = cuttlefish:conf_get("max_last_will_delay", Conf),
- case vmq_schema:string_to_secs(S) of
- error ->
- cuttlefish:invalid(S ++ " must be an integer followed by one of 's', 'h', 'd', 'w', 'm', 'y' for second, minute, hour, day, week, month, and year");
- Val -> Val
+ case S of
+ "client" ->
+ %% 2^32 max seconds in a Four Byte Integer
+ 4294967296;
+ _ ->
+ case vmq_schema:string_to_secs(S) of
+ error ->
+ cuttlefish:invalid(S ++ " must be an integer followed by one of 's', 'h', 'd', 'w', 'm', 'y' for second, minute, hour, day, week, month, and year");
+ Val -> Val
+ end
  end
  end}.
 

changelog.md

@@ -27,6 +27,9 @@
 - Fix bug in `vmq_diversity` and `vmq_webhooks` where the plugin hooks would be
  registered out of order, even though the plugins themselves would be started
  in the correct order (#1295).
+- Add new `max_last_will_delay` value `client` which means the value from the
+ client is used instead of being overriden by the broker. This `client` value
+ is now the default. This setting only applies to MQTT 5.0 clients.
 
 ## VerneMQ 1.9.1