Remove nodeId from BaseNodeRequest (#43658)

TransportNodesAction provides a mechanism to easily broadcast a request
to many nodes, and collect the respones into a high level response. Each
node has its own request type, with a base class of BaseNodeRequest.
This base request requires passing the nodeId to which the request will
be sent. However, that nodeId is not used anywhere. It is private to the
base class, yet serialized to each node, where the node could just as
easily find the nodeId of the node it is on locally.

This commit removes passing the nodeId through to the node request
creation, and guards its serialization so that we can remove the base
request class altogether in the future.

Author: rjernst

server/src/main/java/org/elasticsearch/action/admin/cluster/node/hotthreads/TransportNodesHotThreadsAction.java

@@ -54,8 +54,8 @@ protected NodesHotThreadsResponse newResponse(NodesHotThreadsRequest request,
     }
 
     @Override
-    protected NodeRequest newNodeRequest(String nodeId, NodesHotThreadsRequest request) {
-        return new NodeRequest(nodeId, request);
+    protected NodeRequest newNodeRequest(NodesHotThreadsRequest request) {
+        return new NodeRequest(request);
     }
 
     @Override
@@ -85,8 +85,7 @@ public static class NodeRequest extends BaseNodeRequest {
         public NodeRequest() {
         }
 
-        NodeRequest(String nodeId, NodesHotThreadsRequest request) {
-            super(nodeId);
+        NodeRequest(NodesHotThreadsRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/node/info/TransportNodesInfoAction.java

@@ -56,8 +56,8 @@ protected NodesInfoResponse newResponse(NodesInfoRequest nodesInfoRequest,
     }
 
     @Override
-    protected NodeInfoRequest newNodeRequest(String nodeId, NodesInfoRequest request) {
-        return new NodeInfoRequest(nodeId, request);
+    protected NodeInfoRequest newNodeRequest(NodesInfoRequest request) {
+        return new NodeInfoRequest(request);
     }
 
     @Override
@@ -79,8 +79,7 @@ public static class NodeInfoRequest extends BaseNodeRequest {
         public NodeInfoRequest() {
         }
 
-        public NodeInfoRequest(String nodeId, NodesInfoRequest request) {
-            super(nodeId);
+        public NodeInfoRequest(NodesInfoRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/node/reload/TransportNodesReloadSecureSettingsAction.java

@@ -68,8 +68,8 @@ protected NodesReloadSecureSettingsResponse newResponse(NodesReloadSecureSetting
     }
 
     @Override
-    protected NodeRequest newNodeRequest(String nodeId, NodesReloadSecureSettingsRequest request) {
-        return new NodeRequest(nodeId, request);
+    protected NodeRequest newNodeRequest(NodesReloadSecureSettingsRequest request) {
+        return new NodeRequest(request);
     }
 
     @Override
@@ -116,8 +116,7 @@ public static class NodeRequest extends BaseNodeRequest {
         public NodeRequest() {
         }
 
-        NodeRequest(String nodeId, NodesReloadSecureSettingsRequest request) {
-            super(nodeId);
+        NodeRequest(NodesReloadSecureSettingsRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/TransportNodesStatsAction.java

@@ -55,8 +55,8 @@ protected NodesStatsResponse newResponse(NodesStatsRequest request, List<NodeSta
     }
 
     @Override
-    protected NodeStatsRequest newNodeRequest(String nodeId, NodesStatsRequest request) {
-        return new NodeStatsRequest(nodeId, request);
+    protected NodeStatsRequest newNodeRequest(NodesStatsRequest request) {
+        return new NodeStatsRequest(request);
     }
 
     @Override
@@ -79,8 +79,7 @@ public static class NodeStatsRequest extends BaseNodeRequest {
         public NodeStatsRequest() {
         }
 
-        NodeStatsRequest(String nodeId, NodesStatsRequest request) {
-            super(nodeId);
+        NodeStatsRequest(NodesStatsRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/node/usage/TransportNodesUsageAction.java

@@ -53,8 +53,8 @@ protected NodesUsageResponse newResponse(NodesUsageRequest request, List<NodeUsa
     }
 
     @Override
-    protected NodeUsageRequest newNodeRequest(String nodeId, NodesUsageRequest request) {
-        return new NodeUsageRequest(nodeId, request);
+    protected NodeUsageRequest newNodeRequest(NodesUsageRequest request) {
+        return new NodeUsageRequest(request);
     }
 
     @Override
@@ -75,8 +75,7 @@ public static class NodeUsageRequest extends BaseNodeRequest {
         public NodeUsageRequest() {
         }
 
-        NodeUsageRequest(String nodeId, NodesUsageRequest request) {
-            super(nodeId);
+        NodeUsageRequest(NodesUsageRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java

@@ -68,8 +68,8 @@ public TransportNodesSnapshotsStatus(ThreadPool threadPool, ClusterService clust
     }
 
     @Override
-    protected NodeRequest newNodeRequest(String nodeId, Request request) {
-        return new NodeRequest(nodeId, request);
+    protected NodeRequest newNodeRequest(Request request) {
+        return new NodeRequest(request);
     }
 
     @Override
@@ -168,8 +168,7 @@ public static class NodeRequest extends BaseNodeRequest {
         public NodeRequest() {
         }
 
-        NodeRequest(String nodeId, TransportNodesSnapshotsStatus.Request request) {
-            super(nodeId);
+        NodeRequest(TransportNodesSnapshotsStatus.Request request) {
             snapshots = Arrays.asList(request.snapshots);
         }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/stats/TransportClusterStatsAction.java

@@ -81,8 +81,8 @@ protected ClusterStatsResponse newResponse(ClusterStatsRequest request,
     }
 
     @Override
-    protected ClusterStatsNodeRequest newNodeRequest(String nodeId, ClusterStatsRequest request) {
-        return new ClusterStatsNodeRequest(nodeId, request);
+    protected ClusterStatsNodeRequest newNodeRequest(ClusterStatsRequest request) {
+        return new ClusterStatsNodeRequest(request);
     }
 
     @Override
@@ -142,8 +142,7 @@ public static class ClusterStatsNodeRequest extends BaseNodeRequest {
         public ClusterStatsNodeRequest() {
         }
 
-        ClusterStatsNodeRequest(String nodeId, ClusterStatsRequest request) {
-            super(nodeId);
+        ClusterStatsNodeRequest(ClusterStatsRequest request) {
             this.request = request;
         }
 

server/src/main/java/org/elasticsearch/action/support/nodes/BaseNodeRequest.java

@@ -19,33 +19,31 @@
 
 package org.elasticsearch.action.support.nodes;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+// TODO: this class can be removed in master once 7.x is bumped to 7.4.0
 public abstract class BaseNodeRequest extends TransportRequest {
 
-    private String nodeId;
-
-    public BaseNodeRequest() {
-
-    }
-
-    protected BaseNodeRequest(String nodeId) {
-        this.nodeId = nodeId;
-    }
+    public BaseNodeRequest() {}
 
     @Override
     public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
-        nodeId = in.readString();
+        if (in.getVersion().before(Version.V_7_3_0)) {
+            in.readString(); // previously nodeId
+        }
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeString(nodeId);
+        if (out.getVersion().before(Version.V_7_3_0)) {
+            out.writeString(""); // previously nodeId
+        }
     }
 }

server/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java

@@ -119,7 +119,7 @@ protected NodesResponse newResponse(NodesRequest request, AtomicReferenceArray n
      */
     protected abstract NodesResponse newResponse(NodesRequest request, List<NodeResponse> responses, List<FailedNodeException> failures);
 
-    protected abstract NodeRequest newNodeRequest(String nodeId, NodesRequest request);
+    protected abstract NodeRequest newNodeRequest(NodesRequest request);
 
     protected abstract NodeResponse newNodeResponse();
 
@@ -174,7 +174,7 @@ void start() {
                 final DiscoveryNode node = nodes[i];
                 final String nodeId = node.getId();
                 try {
-                    TransportRequest nodeRequest = newNodeRequest(nodeId, request);
+                    TransportRequest nodeRequest = newNodeRequest(request);
                     if (task != null) {
                         nodeRequest.setParentTask(clusterService.localNode().getId(), task.getId());
                     }

server/src/main/java/org/elasticsearch/gateway/TransportNodesListGatewayMetaState.java

@@ -67,8 +67,8 @@ public ActionFuture<NodesGatewayMetaState> list(String[] nodesIds, @Nullable Tim
     }
 
     @Override
-    protected NodeRequest newNodeRequest(String nodeId, Request request) {
-        return new NodeRequest(nodeId);
+    protected NodeRequest newNodeRequest(Request request) {
+        return new NodeRequest();
     }
 
     @Override
@@ -114,14 +114,6 @@ protected void writeNodesTo(StreamOutput out, List<NodeGatewayMetaState> nodes)
     }
 
     public static class NodeRequest extends BaseNodeRequest {
-
-        public NodeRequest() {
-        }
-
-        NodeRequest(String nodeId) {
-            super(nodeId);
-        }
-
     }
 
     public static class NodeGatewayMetaState extends BaseNodeResponse {