Remove unused TracingPlugin interface

server/src/main/java/org/elasticsearch/node/Node.java

@@ -147,7 +147,6 @@
 import org.elasticsearch.plugins.SearchPlugin;
 import org.elasticsearch.plugins.ShutdownAwarePlugin;
 import org.elasticsearch.plugins.SystemIndexPlugin;
-import org.elasticsearch.plugins.TracingPlugin;
 import org.elasticsearch.repositories.RepositoriesModule;
 import org.elasticsearch.repositories.RepositoriesService;
 import org.elasticsearch.rest.RestController;
@@ -171,6 +170,7 @@
 import org.elasticsearch.tasks.TaskTracer;
 import org.elasticsearch.threadpool.ExecutorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.tracing.Tracer;
 import org.elasticsearch.transport.Transport;
 import org.elasticsearch.transport.TransportInterceptor;
 import org.elasticsearch.transport.TransportService;
@@ -753,9 +753,7 @@ protected Node(
             final IndexingPressure indexingLimits = new IndexingPressure(settings);
 
             final TaskTracer taskTracer = transportService.getTaskManager().getTaskTracer();
-            pluginComponents.stream()
-                .map(c -> c instanceof TracingPlugin.Tracer ? (TracingPlugin.Tracer) c : null)
-                .forEach(taskTracer::addTracer);
+            pluginComponents.stream().map(c -> c instanceof Tracer ? (Tracer) c : null).forEach(taskTracer::addTracer);
 
             final RecoverySettings recoverySettings = new RecoverySettings(settings, settingsModule.getClusterSettings());
             RepositoriesModule repositoriesModule = new RepositoriesModule(

server/src/main/java/org/elasticsearch/tasks/Task.java

@@ -11,7 +11,7 @@
 import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.io.stream.NamedWriteable;
-import org.elasticsearch.plugins.TracingPlugin;
+import org.elasticsearch.tracing.Traceable;
 import org.elasticsearch.xcontent.ToXContent;
 import org.elasticsearch.xcontent.ToXContentObject;
 
@@ -21,7 +21,7 @@
 /**
  * Current task information
  */
-public class Task implements TracingPlugin.Traceable {
+public class Task implements Traceable {
 
     /**
      * The request header to mark tasks with specific ids

server/src/main/java/org/elasticsearch/tasks/TaskTracer.java

@@ -11,7 +11,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.elasticsearch.plugins.TracingPlugin;
+import org.elasticsearch.tracing.Tracer;
 
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
@@ -20,16 +20,16 @@ public class TaskTracer {
 
     private static final Logger logger = LogManager.getLogger();
 
-    private final List<TracingPlugin.Tracer> tracers = new CopyOnWriteArrayList<>();
+    private final List<Tracer> tracers = new CopyOnWriteArrayList<>();
 
-    public void addTracer(TracingPlugin.Tracer tracer) {
+    public void addTracer(Tracer tracer) {
         if (tracer != null) {
             tracers.add(tracer);
         }
     }
 
     public void onTaskRegistered(Task task) {
-        for (TracingPlugin.Tracer tracer : tracers) {
+        for (Tracer tracer : tracers) {
             try {
                 tracer.onTraceStarted(task);
             } catch (Exception e) {
@@ -48,7 +48,7 @@ public void onTaskRegistered(Task task) {
     }
 
     public void onTaskUnregistered(Task task) {
-        for (TracingPlugin.Tracer tracer : tracers) {
+        for (Tracer tracer : tracers) {
             try {
                 tracer.onTraceStopped(task);
             } catch (Exception e) {

server/src/main/java/org/elasticsearch/tracing/Traceable.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.tracing;
+
+import java.util.Map;
+
+/**
+ * Something which maps onto a <i>span</i> in a distributed trace.
+ */
+public interface Traceable {
+
+    /**
+     * @return a key which uniquely identifies the span.
+     */
+    String getSpanId();
+
+    /**
+     * @return the name of the span as seen by the external tracing system (e.g. the action name for a task)
+     */
+    String getSpanName();
+
+    /**
+     * @return extra metadata about the span.
+     */
+    Map<String, Object> getAttributes();
+}

server/src/main/java/org/elasticsearch/tracing/Tracer.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.tracing;
+
+/**
+ * Represents a distributed tracing system that keeps track of the start and end of various activities in the cluster.
+ */
+public interface Tracer {
+
+    /**
+     * Called when the {@link Traceable} activity starts.
+     */
+    void onTraceStarted(Traceable traceable);
+
+    /**
+     * Called when the {@link Traceable} activity ends.
+     */
+    void onTraceStopped(Traceable traceable);
+}

x-pack/plugin/apm-integration/src/internalClusterTest/java/org/elasticsearch/xpack/apm/ApmIT.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.index.query.RangeQueryBuilder;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.plugins.PluginsService;
-import org.elasticsearch.plugins.TracingPlugin;
 import org.elasticsearch.tasks.Task;
 import org.elasticsearch.tasks.TaskId;
 import org.elasticsearch.tasks.TaskTracer;
@@ -64,7 +63,7 @@ public void clearRecordedSpans() {
     }
 
     public void testModule() {
-        List<TracingPlugin> plugins = internalCluster().getMasterNodeInstance(PluginsService.class).filterPlugins(TracingPlugin.class);
+        List<APM> plugins = internalCluster().getMasterNodeInstance(PluginsService.class).filterPlugins(APM.class);
         assertThat(plugins, hasSize(1));
 
         TransportService transportService = internalCluster().getInstance(TransportService.class);

x-pack/plugin/apm-integration/src/main/java/org/elasticsearch/xpack/apm/APM.java

@@ -19,7 +19,6 @@
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.plugins.NetworkPlugin;
 import org.elasticsearch.plugins.Plugin;
-import org.elasticsearch.plugins.TracingPlugin;
 import org.elasticsearch.repositories.RepositoriesService;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.tasks.Task;
@@ -38,7 +37,7 @@
 import java.util.Set;
 import java.util.function.Supplier;
 
-public class APM extends Plugin implements TracingPlugin, NetworkPlugin {
+public class APM extends Plugin implements NetworkPlugin {
 
     public static final Set<String> TRACE_HEADERS = Set.of(Task.TRACE_PARENT, Task.TRACE_STATE);
 

x-pack/plugin/apm-integration/src/main/java/org/elasticsearch/xpack/apm/APMTracer.java

@@ -38,9 +38,9 @@
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
-import org.elasticsearch.plugins.TracingPlugin;
 import org.elasticsearch.tasks.Task;
 import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.tracing.Traceable;
 
 import java.security.AccessController;
 import java.security.PrivilegedAction;
@@ -55,7 +55,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-public class APMTracer extends AbstractLifecycleComponent implements TracingPlugin.Tracer {
+public class APMTracer extends AbstractLifecycleComponent implements org.elasticsearch.tracing.Tracer {
 
     public static final CapturingSpanExporter CAPTURING_SPAN_EXPORTER = new CapturingSpanExporter();
 
@@ -122,7 +122,7 @@ protected void doStop() {
     protected void doClose() {}
 
     @Override
-    public void onTraceStarted(TracingPlugin.Traceable traceable) {
+    public void onTraceStarted(Traceable traceable) {
         final Tracer tracer = this.tracer;
         final OpenTelemetry openTelemetry = this.openTelemetry;
         if (openTelemetry != null && tracer != null) {
@@ -190,7 +190,7 @@ public Map<String, String> getSpanHeadersById(String id) {
     }
 
     @Override
-    public void onTraceStopped(TracingPlugin.Traceable traceable) {
+    public void onTraceStopped(Traceable traceable) {
         final Span span = spans.remove(traceable.getSpanId());
         if (span != null) {
             span.end();