lib/semantic_logger/formatters/logfmt.rb in semantic_logger-4.8.2 vs lib/semantic_logger/formatters/logfmt.rb in semantic_logger-4.9.0

@@ -1,9 +1,24 @@
 require "json"
 
 module SemanticLogger
   module Formatters
+    # Produces logfmt formatted messages
+    #
+    # The following fields are extracted from the raw log and included in the formatted message:
+    #   :timestamp, :level, :name, :message, :duration, :tags, :named_tags
+    #
+    # E.g.
+    #   timestamp="2020-07-20T08:32:05.375276Z" level=info name="DefaultTest" base="breakfast" spaces="second breakfast" double_quotes="\"elevensies\"" single_quotes="'lunch'" tag="success"
+    #
+    # All timestamps are ISO8601 formatteed
+    # All user supplied values are escaped and surrounded by double quotes to avoid ambiguious message delimeters
+    # `tags` are treated as keys with boolean values. Tag names are not formatted or validated, ensure you use valid logfmt format for tag names.
+    # `named_tags` are flattened are merged into the top level message field. Any conflicting fields are overridden.
+    # `payload` values take precedence over `tags` and `named_tags`. Any conflicting fields are overridden.
+    #
+    # Futher Reading https://brandur.org/logfmt
     class Logfmt < Raw
       def initialize(time_format: :iso_8601, time_key: :timestamp, **args)
         super(time_format: time_format, time_key: time_key, **args)
       end
 
@@ -14,17 +29,26 @@
       end
 
       private
 
       def raw_to_logfmt
-        @parsed = @raw.slice(:timestamp, :level, :name, :message, :duration).merge tag: "success"
+        @parsed = @raw.slice(time_key, :level, :name, :message, :duration).merge(tag: "success")
+        handle_tags
         handle_payload
         handle_exception
 
         flatten_log
       end
 
+      def handle_tags
+        tags = @raw.fetch(:tags){ [] }
+                    .each_with_object({}){ |tag, accum| accum[tag] = true }
+
+        @parsed = @parsed.merge(tags)
+                         .merge(@raw.fetch(:named_tags){ {} })
+      end
+
       def handle_payload
         return unless @raw.key? :payload
 
         @parsed = @parsed.merge(@raw[:payload])
       end
@@ -36,19 +60,13 @@
         @parsed = @parsed.merge(@raw[:exception])
       end
 
       def flatten_log
         flattened = @parsed.map do |key, value|
-          "#{key}=#{parse_value(value)}"
+          "#{key}=#{value.to_json}"
         end
 
         flattened.join(" ")
-      end
-
-      def parse_value(value)
-        return value.to_json if value.instance_of? String
-
-        value
       end
     end
   end
 end