add new csv formatter

lib/fluent/formatter.rb

@@ -142,6 +142,37 @@ def format(tag, time, record)
       end
     end
 
+    class CsvFormatter
+      include Configurable
+      include HandleTagAndTimeMixin
+
+      config_param :delimiter, :default => ',' do |val|
+        ['\t', 'TAB'].include?(val) ? "\t" : val
+      end
+      config_param :force_quotes, :bool, :default => true
+      config_param :fields, :default => [] do |val|
+        val.split(',').map do |f|
+          f.strip!
+          f.size > 0 ? f : nil
+        end.compact
+      end
+
+      def initialize
+        super
+        require 'csv'
+      end
+
+      def format(tag, time, record)
+        filter_record(tag, time, record)
+        row = @fields.inject([]) do |memo, key|
+            memo << record[key]
+            memo
+        end
+        CSV.generate_line(row, :col_sep => @delimiter,
+                          :force_quotes => @force_quotes)
+      end
+    end
+
     class SingleValueFormatter
       include Configurable
 
@@ -161,6 +192,7 @@ def format(tag, time, record)
       'json' => Proc.new { JSONFormatter.new },
       'msgpack' => Proc.new { MessagePackFormatter.new },
       'ltsv' => Proc.new { LabeledTSVFormatter.new },
+      'csv' => Proc.new { CsvFormatter.new },
       'single_value' => Proc.new { SingleValueFormatter.new },
     }.each { |name, factory|
       TEMPLATE_REGISTRY.register(name, factory)

test/test_formatter.rb

@@ -217,6 +217,118 @@ def test_format_with_customized_delimiters
     end
   end
 
+  class CsvFormatterTest < ::Test::Unit::TestCase
+    include FormatterTest
+
+    def setup
+      @formatter = TextFormatter::CsvFormatter.new
+      @time = Engine.now
+    end
+
+    def test_config_params
+      assert_equal ',', @formatter.delimiter
+      assert_equal true, @formatter.force_quotes
+      assert_equal [], @formatter.fields
+    end
+
+    data(
+      'tab_char' => ["\t", '\t'],
+      'tab_string' => ["\t", 'TAB'],
+      'pipe' => ['|', '|'])
+    def test_config_params_with_customized_delimiters(data)
+      expected, target = data
+      @formatter.configure('delimiter' => target)
+      assert_equal expected, @formatter.delimiter
+    end
+
+    def test_format
+      @formatter.configure('fields' => 'message,message2')
+      formatted = @formatter.format(tag, @time, {
+        'message' => 'awesome',
+        'message2' => 'awesome2'
+      })
+      assert_equal("\"awesome\",\"awesome2\"\n", formatted)
+    end
+
+    def test_format_with_tag
+      @formatter.configure(
+        'fields' => 'tag,message,message2',
+        'include_tag_key' => 'true'
+      )
+      formatted = @formatter.format(tag, @time, {
+        'message' => 'awesome',
+        'message2' => 'awesome2'
+      })
+      assert_equal("\"tag\",\"awesome\",\"awesome2\"\n", formatted)
+    end
+
+    def test_format_with_time
+      @formatter.configure(
+        'fields' => 'time,message,message2',
+        'include_time_key' => 'true',
+        'time_format' => '%Y'
+      )
+      formatted = @formatter.format(tag, @time, {
+        'message' => 'awesome',
+        'message2' => 'awesome2'
+      })
+      assert_equal("\"#{Time.now.year}\",\"awesome\",\"awesome2\"\n",
+                   formatted)
+    end
+
+    def test_format_with_customized_delimiters
+      @formatter.configure(
+        'fields' => 'message,message2',
+        'delimiter' => '\t'
+      )
+      formatted = @formatter.format(tag, @time, {
+        'message' => 'awesome',
+        'message2' => 'awesome2'
+      })
+      assert_equal("\"awesome\"\t\"awesome2\"\n", formatted)
+    end
+
+    def test_format_with_non_quote
+      @formatter.configure(
+        'fields' => 'message,message2',
+        'force_quotes' => 'false'
+      )
+      formatted = @formatter.format(tag, @time, {
+        'message' => 'awesome',
+        'message2' => 'awesome2'
+      })
+      assert_equal("awesome,awesome2\n", formatted)
+    end
+
+    data(
+      'nil' => {
+        'message' => 'awesome',
+        'message2' => nil,
+        'message3' => 'awesome3'
+      },
+      'blank' => {
+        'message' => 'awesome',
+        'message2' => '',
+        'message3' => 'awesome3'
+      })
+    def test_format_with_empty_fields(data)
+      @formatter.configure(
+        'fields' => 'message,message2,message3'
+      )
+      formatted = @formatter.format(tag, @time, data)
+      assert_equal("\"awesome\",\"\",\"awesome3\"\n", formatted)
+    end
+
+    data(
+      'normally' => 'one,two,three',
+      'white_space' => 'one , two , three',
+      'blank' => 'one,,two,three')
+    def test_config_params_with_fields(data)
+      @formatter.configure('fields' => data)
+      assert_equal %w(one two three), @formatter.fields
+    end
+  end
+
   class SingleValueFormatterTest < ::Test::Unit::TestCase
     include FormatterTest