From 750e57187888347e59d3615183d4c3194fd2d9e8 Mon Sep 17 00:00:00 2001
From: TAGOMORI Satoshi <tagomoris@gmail.com>
Date: Wed, 18 Mar 2015 17:30:41 +0900
Subject: [PATCH] Add plugin name and its id (if exists) as header of plugin
 logs

---
 lib/fluent/log.rb | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/fluent/log.rb b/lib/fluent/log.rb
index 20feacab0a..8d3530c75a 100644
--- a/lib/fluent/log.rb
+++ b/lib/fluent/log.rb
@@ -67,6 +67,8 @@ def initialize(out=STDERR, level=LEVEL_TRACE, opts={})
 
       # Fluent::Engine requires Fluent::Log, so we must take that object lazily
       @engine = Fluent.const_get('Engine')
+      @optional_header = nil
+      @optional_attrs = nil
 
       @suppress_repeated_stacktrace = opts[:suppress_repeated_stacktrace]
     end
@@ -75,6 +77,7 @@ def initialize(out=STDERR, level=LEVEL_TRACE, opts={})
     attr_accessor :level
     attr_accessor :tag
     attr_accessor :time_format
+    attr_accessor :optional_header, :optional_attrs
 
     def enable_debug(b=true)
       @debug_mode = b
@@ -268,8 +271,8 @@ def dump_stacktrace(backtrace, level)
 
     def event(level, args)
       time = Time.now
-      message = ''
-      map = {}
+      message = @optional_header ? @optional_header.dup : ''
+      map = @optional_attrs ? @optional_attrs.dup : {}
       args.each {|a|
         if a.is_a?(Hash)
           a.each_pair {|k,v|
@@ -340,6 +343,18 @@ def enable_color(b = true)
       @logger.enable_color b
     end
 
+    def optional_header=(header)
+      @logger.optional_header = header
+    end
+
+    def optional_attrs=(attrs)
+      @logger.optional_attrs = attrs
+    end
+
+    def optional_attrs
+      @logger.optional_attrs
+    end
+
     extend Forwardable
     def_delegators '@logger', :enable_color?, :enable_debug, :enable_event,
       :disable_events, :tag, :tag=, :time_format, :time_format=,
@@ -371,6 +386,8 @@ def configure(conf)
           @log = PluginLogger.new($log)
         end
         @log.level = @log_level
+        @log.optional_header = "[#{self.class.name}#{plugin_id_configured? ? "(" + @id + ")" : ""}] "
+        @log.optional_attrs = {}
       end
     end
   end