chore(config): default log.single_line=true

etc/emqx.conf

@@ -449,10 +449,8 @@ log.file = emqx.log
 #log.formatter = text
 
 ## Log to single line
-## Value: formatter_default | true | false
-## 'formatter_default' is equivalent to 'true' when log.formatter is 'json'
-## 'formatter_default' is equivalent to 'false' when log.formatter is 'text'
-#log.single_line = formatter_default
+## Value: Boolean
+#log.single_line = true
 
 ## Enables the log rotation.
 ## With this enabled, new log files will be created when the current

priv/emqx.schema

@@ -506,8 +506,8 @@ end}.
 
 %% @doc format logs in a single line.
 {mapping, "log.single_line", "kernel.logger", [
-  {default, formatter_default},
-  {datatype, {enum, [formatter_default, true, false]}}
+  {default, true},
+  {datatype, {enum, [true, false]}}
 ]}.
 
 {mapping, "log.rotation", "kernel.logger", [
@@ -606,16 +606,8 @@ end}.
                      -1 -> unlimited;
                      V -> V
                  end,
-    SingleLine0 = cuttlefish:conf_get("log.single_line", Conf),
+    SingleLine = cuttlefish:conf_get("log.single_line", Conf),
     FmtName = cuttlefish:conf_get("log.formatter", Conf),
-    SingleLine = case SingleLine0 =:= formatter_default of
-                     true when FmtName =:= text ->
-                         false;
-                     true when FmtName =:= json ->
-                         true;
-                     false ->
-                         SingleLine0
-                 end,
     Formatter =
     case FmtName of
         json ->