Add cluster UUID

Fixes #10561

Author: cachedout

logstash-core/lib/logstash/api/commands/node.rb

@@ -36,7 +36,8 @@ def pipeline(pipeline_id)
             :config_reload_automatic,
             :config_reload_interval,
             :dead_letter_queue_enabled,
-            :dead_letter_queue_path
+            :dead_letter_queue_path,
+            :cluster_uuids
           ).reject{|_, v|v.nil?}
         rescue
           {}

logstash-core/lib/logstash/java_pipeline.rb

@@ -220,6 +220,7 @@ def start_workers
       config_metric.gauge(:ephemeral_id, ephemeral_id)
       config_metric.gauge(:hash, lir.unique_hash)
       config_metric.gauge(:graph, ::LogStash::Config::LIRSerializer.serialize(lir))
+      config_metric.gauge(:cluster_uuids, resolve_cluster_uuids)
 
       @logger.info("Starting pipeline", default_logging_keys(
         "pipeline.workers" => pipeline_workers,
@@ -258,6 +259,19 @@ def start_workers
     end
   end
 
+  def resolve_cluster_uuids
+    cluster_uuids = []
+    outputs.each do |output|
+      if LogStash::SETTINGS.registered?(output.id + ".cluster_uuid")
+        cluster_uuid = LogStash::SETTINGS.get(output.id + ".cluster_uuid")
+        unless cluster_uuids.include? cluster_uuid
+          cluster_uuids.push(cluster_uuid)
+        end
+      end
+    end
+  cluster_uuids
+  end
+
   def wait_inputs
     @input_threads.each do |thread|
       if thread.class == Java::JavaObject