Allow to define a custom formatter for logs (#1816)

* Allow to define a custom formatter for logs

History.md

@@ -1,7 +1,7 @@
 ## Master
 
 * Features
-  * Your feature goes here (#Github Number)
+  * Add log_formatter configuration (#1816)
 
 * Bugfixes
   * Your bugfix goes here (#Github Number)

lib/puma/dsl.rb

@@ -282,6 +282,10 @@ def stdout_redirect(stdout=nil, stderr=nil, append=false)
       @options[:redirect_append] = append
     end
 
+    def log_formatter(&block)
+      @options[:log_formatter] = block
+    end
+
     # Configure +min+ to be the minimum number of threads to use to answer
     # requests and +max+ the maximum.
     #

lib/puma/launcher.rb

@@ -63,6 +63,9 @@ def initialize(conf, launcher_args={})
       @options = @config.options
       @config.clamp
 
+      @events.formatter = Events::PidFormatter.new if clustered?
+      @events.formatter = options[:log_formatter] if @options[:log_formatter]
+
       generate_restart_data
 
       if clustered? && !Process.respond_to?(:fork)
@@ -81,7 +84,6 @@ def initialize(conf, launcher_args={})
       set_rack_environment
 
       if clustered?
-        @events.formatter = Events::PidFormatter.new
         @options[:logger] = @events
 
         @runner = Cluster.new(self, @events)

test/config/custom_log_formatter.rb

@@ -0,0 +1,3 @@
+log_formatter do |str|
+  "[#{Process.pid}] [#{Socket.gethostname}] #{Time.now}: #{str}"
+end

test/test_cli.rb

@@ -253,6 +253,32 @@ def test_state_file_callback_filtering
     assert_empty keys_not_stripped
   end
 
+  def test_log_formatter_default_single
+    cli = Puma::CLI.new [ ]
+    assert_instance_of Puma::Events::DefaultFormatter, cli.launcher.events.formatter
+  end
+
+  def test_log_formatter_default_clustered
+    skip NO_FORK_MSG unless HAS_FORK
+
+    cli = Puma::CLI.new [ "-w 2" ]
+    assert_instance_of Puma::Events::PidFormatter, cli.launcher.events.formatter
+  end
+
+  def test_log_formatter_custom_single
+    cli = Puma::CLI.new [ "--config", "test/config/custom_log_formatter.rb" ]
+    assert_instance_of Proc, cli.launcher.events.formatter
+    assert_match(/^\[.*\] \[.*\] .*: test$/, cli.launcher.events.format('test'))
+  end
+
+  def test_log_formatter_custom_clustered
+    skip NO_FORK_MSG unless HAS_FORK
+
+    cli = Puma::CLI.new [ "--config", "test/config/custom_log_formatter.rb", "-w 2" ]
+    assert_instance_of Proc, cli.launcher.events.formatter
+    assert_match(/^\[.*\] \[.*\] .*: test$/, cli.launcher.events.format('test'))
+  end
+
   def test_state
     url = "tcp://127.0.0.1:#{next_port}"
     cli = Puma::CLI.new ["--state", @tmp_path, "--control", url]