next try

lib/travis/api/app/base.rb

@@ -28,6 +28,33 @@ def censor(message)
   end
 end
 
+module Sinatra
+  module QuietLogger
+
+    @extensions = %w(png gif jpg jpeg woff tff svg eot css js coffee scss)
+
+    class << self
+      attr_accessor :extensions
+
+      def registered(app)
+        ::Rack::CommonLogger.class_eval <<-PATCH
+          alias call_and_log call
+
+          def call(env)
+            ext = env['REQUEST_PATH'].split('.').last
+            if #{extensions.inspect}.include? ext
+              @app.call(env)
+            else
+              call_and_log(env)
+            end
+          end
+        PATCH
+      end
+    end
+
+  end
+end
+
 
 class Travis::Api::App
   # Superclass for any endpoint and middleware.
@@ -74,9 +101,8 @@ def call(env)
       else
         disable  :logging, :dump_errors
       end
+      register QuietLogger
 
-      logger = CensoredLogger.new(File.open('/var/log/travis.log', 'a'))
-      set :logger, logger
       register :subclass_tracker, :expose_pattern
       helpers  :respond_with, :mime_types
     end