Format UNIX timestamps in encoders and preserve pre-formatted Strings

lib/rackstash/encoder/helper/timestamp.rb

@@ -31,25 +31,30 @@ module Rackstash
         # @return [Hash] the given event with the `field` key set as an ISO 8601
         #   formatted time string.
         def normalize_timestamp(event, field = FIELD_TIMESTAMP, force: false) #:doc:
-          time = normalized_time(event[field])
+          time = normalized_timestamp(event[field])
-          time ||= Time.now.utc if force
+          time ||= Time.now.utc.iso8601(ISO8601_PRECISION) if force
-
-          event[field] = time.iso8601(ISO8601_PRECISION) if time
 
+          event[field] = time if time
           event
         end
 
-        # @param time [Time, DateTime, Date, Integer, Float]
+        # @param time [Time, DateTime, Date, Integer, Float, String]
-        # @return [Time, nil] a `Time` object on UTC timezone if the given
+        # @return [String, nil] the passed time object tramsformed into an UTC
-        #   `time` could be normalized as such or `nil` if the value does not
+        #   timestamp (if possible) and formatted as an ISO 8601 formatted
-        #   describe a timestamp
+        #   String. If the object could not be interpreted as a time, we return
-        def normalized_time(time) #:doc:
+        #   `nil`.
+        def normalized_timestamp(time) #:doc:
           case time
           when ::Time, ::DateTime
             time = time.to_time
-            time.utc? ? time : time.getutc
+            utc_time = time.utc? ? time : time.getutc
+            utc_time.iso8601(ISO8601_PRECISION)
           when ::Date
-            ::Time.new(time.year, time.month, time.day, 0, 0, 0, 0).utc
+            time.iso8601
+          when Integer, Float
+            Time.at(time.to_f).utc.iso8601(ISO8601_PRECISION)
+          when String
+            time.to_s
           end
         end
       end

spec/rackstash/encoder/helper/timestamp_spec.rb

@@ -37,7 +37,17 @@ RSpec.describe Rackstash::Encoder::Helper::Timestamp do
     it 'formats a Date object' do
       event['@timestamp'] = Date.new(2016, 10, 17)
       expect(helper.normalize_timestamp(event).fetch('@timestamp'))
-        .to eql '2016-10-17T00:00:00.000000Z'
+        .to eql '2016-10-17'
+    end
+
+    it 'formats a UNIX timestamp' do
+      event['@timestamp'] = 1526499065
+      expect(helper.normalize_timestamp(event).fetch('@timestamp'))
+        .to eql '2018-05-16T19:31:05.000000Z'
+
+      event['@timestamp'] = 1526499065.4177752
+      expect(helper.normalize_timestamp(event).fetch('@timestamp'))
+        .to eql '2018-05-16T19:31:05.417775Z'
     end
 
     it 'ignores an unset value by default' do
@@ -50,12 +60,6 @@ RSpec.describe Rackstash::Encoder::Helper::Timestamp do
 
       event['@timestamp'] = nil
       expect(helper.normalize_timestamp(event).fetch('@timestamp')).to eql nil
-
-      event['@timestamp'] = 123
-      expect(helper.normalize_timestamp(event).fetch('@timestamp')).to eql 123
-
-      event['@timestamp'] = 3.14
-      expect(helper.normalize_timestamp(event).fetch('@timestamp')).to eql 3.14
     end
 
     it 'uses the given field name' do
@@ -81,7 +85,7 @@ RSpec.describe Rackstash::Encoder::Helper::Timestamp do
       end
 
       it 'uses the current time for unknown values' do
-        event['@timestamp'] = 'string'
+        event['@timestamp'] = Object.new
         expect(helper.normalize_timestamp(event, force: true).fetch('@timestamp'))
           .to eql '2016-10-17T10:37:00.000000Z'