Metadata whitelist

src/lager_default_formatter.erl

@@ -57,15 +57,11 @@
 format(Msg,[], Colors) ->
     format(Msg, [{eol, "\n"}], Colors);
 format(Msg,[{eol, EOL}], Colors) ->
-    format(Msg,
-        [date, " ", time, " ", color, "[", severity, "] ",
-            {pid, ""},
-            {module, [
-                    {pid, ["@"], ""},
-                    module,
-                    {function, [":", function], ""},
-                    {line, [":",line], ""}], ""},
-            " ", message, EOL], Colors);
+    Config = case application:get_env(lager, metadata_whitelist) of
+        undefined -> config(EOL, []);
+        {ok, Whitelist} -> config(EOL, Whitelist)
+    end,
+    format(Msg, Config, Colors);
 format(Message,Config,Colors) ->
     [ case V of
         color -> output_color(Message,Colors);
@@ -211,6 +207,33 @@ get_metadata(Key, Metadata, Default) ->
             Value
     end.
 
+config(EOL, []) ->
+    [
+        date, " ", time, " ", color, "[", severity, "] ",
+        {pid, ""},
+        {module, [
+            {pid, ["@"], ""},
+            module,
+            {function, [":", function], ""},
+            {line, [":",line], ""}], ""},
+        " ", message, EOL
+    ];
+config(EOL, MetaWhitelist) ->
+    [
+        date, " ", time, " ", color, "[", severity, "] ",
+        {pid, ""},
+        {module, [
+            {pid, ["@"], ""},
+            module,
+            {function, [":", function], ""},
+            {line, [":",line], ""}], ""},
+        " "
+    ] ++
+    [{M, [atom_to_list(M), "=", M, " "], ""}|| M <- MetaWhitelist] ++
+    [message, EOL].
+
+
+
 uppercase_severity(debug) -> "DEBUG";
 uppercase_severity(info) -> "INFO";
 uppercase_severity(notice) -> "NOTICE";

test/lager_metadata_whitelist_test.erl

@@ -0,0 +1,72 @@
+
+-module(lager_metadata_whitelist_test).
+
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+
+setup() ->
+    ok = error_logger:tty(false),
+    ok = lager_util:safe_application_load(lager),
+    ok = application:set_env(lager, handlers, [{lager_common_test_backend, info}]),
+    ok = application:set_env(lager, error_logger_redirect, false),
+    ok = application:unset_env(lager, traces),
+    ok = lager:start(),
+    ok = timer:sleep(250),
+    ok.
+
+cleanup(_) ->
+    ok = application:unset_env(lager, metadata_whitelist),
+    catch ets:delete(lager_config), %% kill the ets config table with fire
+    ok = application:stop(lager),
+    ok = application:stop(goldrush),
+    ok = error_logger:tty(true).
+
+date_time_now() ->
+    Now = os:timestamp(),
+    {Date, Time} = lager_util:format_time(lager_util:maybe_utc(lager_util:localtime_ms(Now))),
+    {Date, Time, Now}.
+
+basic_test_() ->
+    {Date, Time, Now} = date_time_now(),
+    {
+        foreach,
+        fun setup/0,
+        fun cleanup/1,
+        [{"Meta", fun() ->
+             Whitelist = [meta0],
+            ok = application:set_env(lager, metadata_whitelist, Whitelist),
+            Msg = lager_msg:new("Message", Now, error, [], []),
+            Expected = iolist_to_binary([Date, " ", Time,  " [error]  Message\n"]),
+            Got = iolist_to_binary(lager_default_formatter:format(Msg, [])),
+            ?assertEqual(Expected, Got)
+         end},
+            {"Meta1", fun() ->
+            Whitelist = [meta1],
+            ok = application:set_env(lager, metadata_whitelist, Whitelist),
+            Msg = lager_msg:new("Message", Now, error, [{meta1, "value1"}], []),
+            Expected = iolist_to_binary([Date, " ", Time,  " [error]  meta1=value1 Message\n"]),
+            Got = iolist_to_binary(lager_default_formatter:format(Msg, [])),
+            ?assertEqual(Expected, Got)
+         end},
+         {"Meta2", fun() ->
+            Whitelist = [meta1, meta2],
+            ok = application:set_env(lager, metadata_whitelist, Whitelist),
+            Msg = lager_msg:new("Message", Now, error, [{meta1, "value1"}, {meta2, 2}], []),
+            Expected = iolist_to_binary([Date, " ", Time,  " [error]  meta1=value1 meta2=2 Message\n"]),
+            Got = iolist_to_binary(lager_default_formatter:format(Msg, [])),
+            ?assertEqual(Expected, Got)
+         end},
+         {"Meta3", fun() ->
+            Whitelist = [meta1, meta2],
+            ok = application:set_env(lager, metadata_whitelist, Whitelist),
+            Msg = lager_msg:new("Message", Now, error, [{meta1, "value1"}, {meta3, 3}], []),
+            Expected = iolist_to_binary([Date, " ", Time,  " [error]  meta1=value1 Message\n"]),
+            Got = iolist_to_binary(lager_default_formatter:format(Msg, [])),
+            ?assertEqual(Expected, Got)
+         end}
+        ]
+    }.
+
+
+-endif.