add a broadcasting logger so we can split logs

activesupport/lib/active_support/logger.rb

@@ -1,6 +1,29 @@
 require 'logger'
 
 module ActiveSupport
+  # Broadcasts logs to multiple loggers
+  class BroadcastLogger < ::Logger # :nodoc:
+    attr_reader :logs
+
+    def initialize(logs)
+      super(nil)
+      @logs = logs
+    end
+
+    def add(severity, message = nil, progname = nil, &block)
+      super
+      logs.each { |l| l.add(severity, message, progname, &block) }
+    end
+
+    def <<(x)
+      logs.each { |l| l << x }
+    end
+
+    def close
+      logs.each(&:close)
+    end
+  end
+
   class Logger < ::Logger
     def initialize(*args)
       super

activesupport/test/broadcast_logger_test.rb

@@ -0,0 +1,57 @@
+require 'abstract_unit'
+
+module ActiveSupport
+  class BroadcastLoggerTest < TestCase
+    def test_debug
+      log1 = FakeLogger.new
+      log2 = FakeLogger.new
+
+      logger = BroadcastLogger.new [log1, log2]
+      logger.debug "foo"
+      assert_equal 'foo', log1.adds.first[2]
+      assert_equal 'foo', log2.adds.first[2]
+    end
+
+    def test_close
+      log1 = FakeLogger.new
+      log2 = FakeLogger.new
+
+      logger = BroadcastLogger.new [log1, log2]
+      logger.close
+      assert log1.closed, 'should be closed'
+      assert log2.closed, 'should be closed'
+    end
+
+    def test_chevrons
+      log1 = FakeLogger.new
+      log2 = FakeLogger.new
+
+      logger = BroadcastLogger.new [log1, log2]
+      logger << "foo"
+      assert_equal %w{ foo }, log1.chevrons
+      assert_equal %w{ foo }, log2.chevrons
+    end
+
+    class FakeLogger
+      attr_reader :adds, :closed, :chevrons
+
+      def initialize
+        @adds     = []
+        @closed   = false
+        @chevrons = []
+      end
+
+      def << x
+        @chevrons << x
+      end
+
+      def add(*args)
+        @adds << args
+      end
+
+      def close
+        @closed = true
+      end
+    end
+  end
+end