Logstash formatter for grape_logging (#31)

* Logstash formatter for grape_logging

* Additional host parameter for Logstash

lib/grape_logging.rb

@@ -2,11 +2,13 @@ require 'grape_logging/multi_io'
 require 'grape_logging/version'
 require 'grape_logging/formatters/default'
 require 'grape_logging/formatters/json'
+require 'grape_logging/formatters/logstash'
 require 'grape_logging/loggers/base'
 require 'grape_logging/loggers/response'
 require 'grape_logging/loggers/filter_parameters'
 require 'grape_logging/loggers/client_env'
 require 'grape_logging/loggers/request_headers'
+require 'grape_logging/loggers/logstash'
 require 'grape_logging/reporters/active_support_reporter'
 require 'grape_logging/reporters/logger_reporter'
 require 'grape_logging/timings'

lib/grape_logging/formatters/logstash.rb

@@ -0,0 +1,35 @@
+module GrapeLogging
+  module Formatters
+    class Logstash
+      def call(severity, datetime, _, data)
+        {
+          :'@timestamp' => datetime.iso8601,
+          :'@version' => '1',
+          :severity => severity
+        }.merge!(format(data)).to_json
+      end
+
+      private
+
+      def format(data)
+        if data.is_a?(Hash)
+          data
+        elsif data.is_a?(String)
+          { message: data }
+        elsif data.is_a?(Exception)
+          format_exception(data)
+        else
+          { message: data.inspect }
+        end
+      end
+
+      def format_exception(exception)
+        {
+          exception: {
+            message: exception.message
+          }
+        }
+      end
+    end
+  end
+end

lib/grape_logging/middleware/request_logger.rb

@@ -58,7 +58,8 @@ module GrapeLogging
           },
           method: request.request_method,
           path: request.path,
-          params: request.params
+          params: request.params,
+          host: request.host
         }
       end