DEV: Expose AI spam scanning metrics

Author: nattsw

lib/ai_moderation/spam_metric.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module AiModeration
+    class SpamMetric
+      def self.update(new_status, reviewable)
+        ai_spam_log = AiSpamLog.find_by(reviewable:)
+        return if ai_spam_log.nil?
+
+        increment("scanned")
+        increment("is_spam") if new_status == :approved && ai_spam_log.is_spam
+        increment("false_positive") if new_status == :rejected && ai_spam_log.is_spam
+        increment("false_negative") if new_status == :rejected && !ai_spam_log.is_spam
+      end
+
+      private
+
+      def self.increment(type, value = 1)
+        metric = DiscoursePrometheus::InternalMetric::Custom.new
+        metric.name = "discourse_ai_spam_detection"
+        metric.type = "Counter"
+        metric.description = "AI spam scanning statistics"
+        metric.labels = { db: RailsMultisite::ConnectionManagement.current_db, type: }
+        metric.value = value
+        $prometheus_client.send_json(metric.to_h)
+      end
+    end
+  end
+end

plugin.rb

@@ -83,6 +83,9 @@ def self.public_asset_path(name)
 
   on(:reviewable_transitioned_to) do |new_status, reviewable|
     ModelAccuracy.adjust_model_accuracy(new_status, reviewable)
+    if DiscourseAi::AiModeration::SpamScanner.enabled?
+      DiscourseAi::AiModeration::SpamMetric.update(new_status, reviewable)
+    end
   end
 
   if Rails.env.test?