[VANotify] - Update VANotify::DefaultCallback to handle hash or array statsd_tags

config/features.yml

@@ -1434,6 +1434,9 @@ features:
   va_notify_custom_errors:
     actor_type: user
     description: Custom error classes instead of the generic Common::Exceptions::BackendServiceException
+  va_notify_metadata_statsd_tags:
+    actor_type: user
+    description: Allow statsd tags in callback metadata to be a hash or array
   va_online_scheduling:
     actor_type: user
     description: Allows veterans to view their VA and Community Care appointments

modules/va_notify/lib/va_notify/default_callback.rb

@@ -21,10 +21,15 @@ def call
 
     def call_with_metadata
       notification_type = metadata['notification_type']
-      statsd_tags = metadata['statsd_tags']
-      service = statsd_tags['service']
-      function = statsd_tags['function']
-      tags = ["service:#{service}", "function:#{function}"]
+
+      if Flipper.enabled?(:va_notify_metadata_statsd_tags)
+        tags = validate_and_normalize_statsd_tags
+      else
+        statsd_tags = metadata['statsd_tags']
+        service = statsd_tags['service']
+        function = statsd_tags['function']
+        tags = ["service:#{service}", "function:#{function}"]
+      end
 
       case notification_record.status
       when 'delivered'
@@ -64,5 +69,31 @@ def delivered_without_metadata
     def permanent_failure_without_metadata
       StatsD.increment('silent_failure', tags: ['service:none-provided', 'function:none-provided'])
     end
+
+    def validate_and_normalize_statsd_tags
+      statsd_tags = metadata['statsd_tags']
+      required_keys = %w[service function]
+
+      tag_keys, tags = case statsd_tags
+                       when Hash
+                         keys = statsd_tags.keys
+                         tags = statsd_tags.map { |key, value| "#{key}:#{value}" }
+                         [keys, tags]
+                       when Array
+                         keys = statsd_tags.map { |tag| tag.split(':').first }
+                         tags = statsd_tags
+                         [keys, tags]
+                       else
+                         raise TypeError, 'Invalid metadata statsd_tags format: must be a Hash or Array'
+                       end
+
+      missing_keys = required_keys - tag_keys
+      if missing_keys.any?
+        raise KeyError,
+              "Missing required keys in default_callback metadata statsd_tags: #{missing_keys.join(', ')}"
+      end
+
+      tags
+    end
   end
 end