Merge pull request #3018 from lexmag/logger-metadata-fix

Fix the logging with `metadata[:function]`

Author: josevalim

lib/logger/lib/logger.ex

@@ -474,8 +474,8 @@ defmodule Logger do
   defp macro_log(level, chardata, metadata, caller) do
     min_level = Application.get_env(:logger, :compile_time_purge_level, :debug)
     if compare_levels(level, min_level) != :lt do
-      %{module: module, function: function, line: line} = caller
-      caller = [module: module, function: function, line: line]
+      %{module: module, function: fun, line: line} = caller
+      caller = [module: module, function: form_fa(fun), line: line]
       quote do
         Logger.log(unquote(level), unquote(chardata), unquote(caller) ++ unquote(metadata))
       end
@@ -491,6 +491,12 @@ defmodule Logger do
   defp truncate(data, n),
     do: Logger.Utils.truncate(to_string(data), n)
 
+  defp form_fa({name, arity}) do
+    Atom.to_string(name) <> "/" <> Integer.to_string(arity)
+  end
+
+  defp form_fa(nil), do: nil
+
   defp notify(:sync, msg),  do: GenEvent.sync_notify(Logger, msg)
   defp notify(:async, msg), do: GenEvent.notify(Logger, msg)
 end

lib/logger/test/logger/backends/console_test.exs

@@ -43,8 +43,19 @@ defmodule Logger.Backends.ConsoleTest do
     Logger.metadata(user_id: 13)
 
     assert capture_log(fn ->
-      Logger.debug("user_id=13 hello")
-    end) =~ "hello"
+      Logger.debug("hello")
+    end) =~ "user_id=13 hello"
+  end
+
+  test "metadata defaults" do
+    Logger.configure_backend(:console,
+      format: "$metadata", metadata: [:module, :function, :line])
+
+    %{module: mod, function: {name, arity}, line: line} = __ENV__
+
+    assert capture_log(fn ->
+      Logger.debug("hello")
+    end) =~ "module=#{mod} function=#{name}/#{arity} line=#{line + 3}"
   end
 
   test "can configure level" do