Apply fix for health API response to distinguish no master (#819)

Signed-off-by: Mohit Godwani <mgodwan@amazon.com>

Author: mgodwan

rest-api-spec/src/main/resources/rest-api-spec/test/cat.health/10_basic.yml

@@ -12,6 +12,7 @@
                    status        .+ \n
                    node.total    .+ \n
                    node.data     .+ \n
+                   discovered_master .+ \n
                    shards        .+ \n
                    pri           .+ \n
                    relo          .+ \n
@@ -39,6 +40,7 @@
                 \w+            \s+ # status
                 \d+            \s+ # node.total
                 \d+            \s+ # node.data
+                \w+            \s+ # discovered_master
                 \d+            \s+ # shards
                 \d+            \s+ # pri
                 \d+            \s+ # relo
@@ -66,6 +68,7 @@
                 \w+            \s+ # status
                 \d+            \s+ # node.total
                 \d+            \s+ # node.data
+                \w+            \s+ # discovered_master
                 \d+            \s+ # shards
                 \d+            \s+ # pri
                 \d+            \s+ # relo

server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponse.java

@@ -66,6 +66,7 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
     private static final String TIMED_OUT = "timed_out";
     private static final String NUMBER_OF_NODES = "number_of_nodes";
     private static final String NUMBER_OF_DATA_NODES = "number_of_data_nodes";
+    private static final String DISCOVERED_MASTER = "discovered_master";
     private static final String NUMBER_OF_PENDING_TASKS = "number_of_pending_tasks";
     private static final String NUMBER_OF_IN_FLIGHT_FETCH = "number_of_in_flight_fetch";
     private static final String DELAYED_UNASSIGNED_SHARDS = "delayed_unassigned_shards";
@@ -87,6 +88,7 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
                         // ClusterStateHealth fields
                         int numberOfNodes = (int) parsedObjects[i++];
                         int numberOfDataNodes = (int) parsedObjects[i++];
+                        boolean hasDiscoveredMaster = (boolean) parsedObjects[i++];
                         int activeShards = (int) parsedObjects[i++];
                         int relocatingShards = (int) parsedObjects[i++];
                         int activePrimaryShards = (int) parsedObjects[i++];
@@ -106,9 +108,8 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
                             }
                         }
                         ClusterStateHealth stateHealth = new ClusterStateHealth(activePrimaryShards, activeShards, relocatingShards,
-                                initializingShards, unassignedShards, numberOfNodes, numberOfDataNodes, activeShardsPercent, status,
-                                indices);
-
+                                initializingShards, unassignedShards, numberOfNodes, numberOfDataNodes, hasDiscoveredMaster,
+                                activeShardsPercent, status, indices);
                         // ClusterHealthResponse fields
                         String clusterName = (String) parsedObjects[i++];
                         int numberOfPendingTasks = (int) parsedObjects[i++];
@@ -127,6 +128,7 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
         // ClusterStateHealth fields
         PARSER.declareInt(constructorArg(), new ParseField(NUMBER_OF_NODES));
         PARSER.declareInt(constructorArg(), new ParseField(NUMBER_OF_DATA_NODES));
+        PARSER.declareBoolean(constructorArg(), new ParseField(DISCOVERED_MASTER));
         PARSER.declareInt(constructorArg(), new ParseField(ACTIVE_SHARDS));
         PARSER.declareInt(constructorArg(), new ParseField(RELOCATING_SHARDS));
         PARSER.declareInt(constructorArg(), new ParseField(ACTIVE_PRIMARY_SHARDS));
@@ -237,6 +239,10 @@ public int getNumberOfDataNodes() {
         return clusterStateHealth.getNumberOfDataNodes();
     }
 
+    public boolean hasDiscoveredMaster() {
+        return clusterStateHealth.hasDiscoveredMaster();
+    }
+
     public int getNumberOfPendingTasks() {
         return this.numberOfPendingTasks;
     }
@@ -334,6 +340,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.field(TIMED_OUT, isTimedOut());
         builder.field(NUMBER_OF_NODES, getNumberOfNodes());
         builder.field(NUMBER_OF_DATA_NODES, getNumberOfDataNodes());
+        builder.field(DISCOVERED_MASTER, hasDiscoveredMaster());
         builder.field(ACTIVE_PRIMARY_SHARDS, getActivePrimaryShards());
         builder.field(ACTIVE_SHARDS, getActiveShards());
         builder.field(RELOCATING_SHARDS, getRelocatingShards());

server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java

@@ -31,6 +31,7 @@
 
 package org.opensearch.cluster.health;
 
+import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexRoutingTable;
@@ -53,6 +54,7 @@ public final class ClusterStateHealth implements Iterable<ClusterIndexHealth>, W
 
     private final int numberOfNodes;
     private final int numberOfDataNodes;
+    private final boolean hasDiscoveredMaster;
     private final int activeShards;
     private final int relocatingShards;
     private final int activePrimaryShards;
@@ -80,6 +82,7 @@ public ClusterStateHealth(final ClusterState clusterState) {
     public ClusterStateHealth(final ClusterState clusterState, final String[] concreteIndices) {
         numberOfNodes = clusterState.nodes().getSize();
         numberOfDataNodes = clusterState.nodes().getDataNodes().size();
+        hasDiscoveredMaster = clusterState.nodes().getMasterNodeId() != null;
         indices = new HashMap<>();
         for (String index : concreteIndices) {
             IndexRoutingTable indexRoutingTable = clusterState.routingTable().index(index);
@@ -147,6 +150,11 @@ public ClusterStateHealth(final StreamInput in) throws IOException {
         unassignedShards = in.readVInt();
         numberOfNodes = in.readVInt();
         numberOfDataNodes = in.readVInt();
+        if (in.getVersion().onOrAfter(Version.V_1_0_0)) {
+            hasDiscoveredMaster = in.readBoolean();
+        } else {
+            hasDiscoveredMaster = true;
+        }
         status = ClusterHealthStatus.fromValue(in.readByte());
         int size = in.readVInt();
         indices = new HashMap<>(size);
@@ -161,7 +169,7 @@ public ClusterStateHealth(final StreamInput in) throws IOException {
      * For ClusterHealthResponse's XContent Parser
      */
     public ClusterStateHealth(int activePrimaryShards, int activeShards, int relocatingShards, int initializingShards, int unassignedShards,
-            int numberOfNodes, int numberOfDataNodes, double activeShardsPercent, ClusterHealthStatus status,
+            int numberOfNodes, int numberOfDataNodes, boolean hasDiscoveredMaster, double activeShardsPercent, ClusterHealthStatus status,
         Map<String, ClusterIndexHealth> indices) {
         this.activePrimaryShards = activePrimaryShards;
         this.activeShards = activeShards;
@@ -170,6 +178,7 @@ public ClusterStateHealth(int activePrimaryShards, int activeShards, int relocat
         this.unassignedShards = unassignedShards;
         this.numberOfNodes = numberOfNodes;
         this.numberOfDataNodes = numberOfDataNodes;
+        this.hasDiscoveredMaster = hasDiscoveredMaster;
         this.activeShardsPercent = activeShardsPercent;
         this.status = status;
         this.indices = indices;
@@ -215,6 +224,10 @@ public double getActiveShardsPercent() {
         return activeShardsPercent;
     }
 
+    public boolean hasDiscoveredMaster() {
+        return hasDiscoveredMaster;
+    }
+
     @Override
     public Iterator<ClusterIndexHealth> iterator() {
         return indices.values().iterator();
@@ -229,6 +242,9 @@ public void writeTo(final StreamOutput out) throws IOException {
         out.writeVInt(unassignedShards);
         out.writeVInt(numberOfNodes);
         out.writeVInt(numberOfDataNodes);
+        if (out.getVersion().onOrAfter(Version.V_1_0_0)) {
+            out.writeBoolean(hasDiscoveredMaster);
+        }
         out.writeByte(status.value());
         out.writeVInt(indices.size());
         for (ClusterIndexHealth indexHealth : this) {
@@ -242,6 +258,7 @@ public String toString() {
         return "ClusterStateHealth{" +
                 "numberOfNodes=" + numberOfNodes +
                 ", numberOfDataNodes=" + numberOfDataNodes +
+                ", hasDiscoveredMaster=" + hasDiscoveredMaster +
                 ", activeShards=" + activeShards +
                 ", relocatingShards=" + relocatingShards +
                 ", activePrimaryShards=" + activePrimaryShards +
@@ -260,6 +277,7 @@ public boolean equals(Object o) {
         ClusterStateHealth that = (ClusterStateHealth) o;
         return numberOfNodes == that.numberOfNodes &&
                 numberOfDataNodes == that.numberOfDataNodes &&
+                hasDiscoveredMaster == that.hasDiscoveredMaster &&
                 activeShards == that.activeShards &&
                 relocatingShards == that.relocatingShards &&
                 activePrimaryShards == that.activePrimaryShards &&
@@ -272,7 +290,7 @@ public boolean equals(Object o) {
 
     @Override
     public int hashCode() {
-        return Objects.hash(numberOfNodes, numberOfDataNodes, activeShards, relocatingShards, activePrimaryShards, initializingShards,
-                unassignedShards, activeShardsPercent, status, indices);
+        return Objects.hash(numberOfNodes, numberOfDataNodes, hasDiscoveredMaster, activeShards, relocatingShards,
+                activePrimaryShards, initializingShards, unassignedShards, activeShardsPercent, status, indices);
     }
 }

server/src/main/java/org/opensearch/rest/action/cat/RestHealthAction.java

@@ -89,6 +89,7 @@ protected Table getTableWithHeader(final RestRequest request) {
         t.addCell("status", "alias:st;desc:health status");
         t.addCell("node.total", "alias:nt,nodeTotal;text-align:right;desc:total number of nodes");
         t.addCell("node.data", "alias:nd,nodeData;text-align:right;desc:number of nodes that can store data");
+        t.addCell("discovered_master", "alias:dm;text-align:right;desc:discovered master");
         t.addCell("shards", "alias:t,sh,shards.total,shardsTotal;text-align:right;desc:total number of shards");
         t.addCell("pri", "alias:p,shards.primary,shardsPrimary;text-align:right;desc:number of primary shards");
         t.addCell("relo", "alias:r,shards.relocating,shardsRelocating;text-align:right;desc:number of relocating nodes");
@@ -109,6 +110,7 @@ private Table buildTable(final ClusterHealthResponse health, final RestRequest r
         t.addCell(health.getStatus().name().toLowerCase(Locale.ROOT));
         t.addCell(health.getNumberOfNodes());
         t.addCell(health.getNumberOfDataNodes());
+        t.addCell(health.hasDiscoveredMaster());
         t.addCell(health.getActiveShards());
         t.addCell(health.getActivePrimaryShards());
         t.addCell(health.getRelocatingShards());