lib/chronicle/etl/transformers/transformer.rb in chronicle-etl-0.2.4 vs lib/chronicle/etl/transformers/transformer.rb in chronicle-etl-0.3.0

@@ -1,34 +1,64 @@
 module Chronicle
   module ETL
     # Abstract class representing an Transformer for an ETL job
     class Transformer
-      extend Chronicle::ETL::Catalog
+      extend Chronicle::ETL::Registry::SelfRegistering
 
       # Construct a new instance of this transformer. Options are passed in from a Runner
-      # == Paramters:
+      # == Parameters:
       # options::
       #   Options for configuring this Transformer
-      def initialize(options = {}, data)
+      def initialize(options = {}, extraction)
         @options = options
-        @data = data
-        @record = Chronicle::ETL::Models::Activity.new
+        @extraction = extraction
       end
 
       # @abstract Subclass is expected to implement #transform
       # @!method transform
       #   The main entrypoint for transforming a record. Called by a Runner on each extracted record
 
       # The domain or provider-specific id of the record this transformer is working on.
-      # Used for building a cursor so an extractor doesn't have to start from the beginning of a
-      # data source from the beginning.
-      def id; end
+      # It is useful for: 
+      # - de-duping records that might exist in the loader's destination
+      # - building a cursor so an extractor doesn't have to start from the beginning of a 
+      #   a source 
+      def id
+        raise NotImplementedError
+      end
 
       # The domain or provider-specific timestamp of the record this transformer is working on.
       # Used for building a cursor so an extractor doesn't have to start from the beginning of a
       # data source from the beginning.
-      def timestamp; end
+      def timestamp
+        raise NotImplementedError
+      end
+
+      # An optional, human-readable identifier for a transformation, intended for debugging or logging.
+      # By default, it is just the id.
+      def friendly_identifier
+        id
+      end
+
+      def to_s
+        ts = begin
+          unknown = "???"
+          timestamp&.iso8601 || unknown
+        rescue TransformationError, NotImplementedError
+          unknown
+        end
+
+        identifier = begin
+          unknown = self.class.to_s
+          friendly_identifier || self.class.to_s
+        rescue TransformationError, NotImplementedError
+          unknown
+        end
+
+        "[#{ts}] #{identifier}"
+      end
     end
   end
 end
 
 require_relative 'null_transformer'
+require_relative 'image_file_transformer'