Enable node roles to be pluggable (#43175)

This commit introduces the possibility for a plugin to introduce
additional node roles.

benchmarks/src/main/java/org/elasticsearch/benchmark/routing/allocation/Allocators.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.cluster.ClusterModule;
 import org.elasticsearch.cluster.EmptyClusterInfoService;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.allocation.AllocationService;
 import org.elasticsearch.cluster.routing.allocation.FailedShard;
@@ -92,7 +93,7 @@ public static AllocationDeciders defaultAllocationDeciders(Settings settings, Cl
 
     public static DiscoveryNode newNode(String nodeId, Map<String, String> attributes) {
         return new DiscoveryNode("", nodeId, new TransportAddress(TransportAddress.META_ADDRESS,
-            portGenerator.incrementAndGet()), attributes, Sets.newHashSet(DiscoveryNode.Role.MASTER,
-            DiscoveryNode.Role.DATA), Version.CURRENT);
+            portGenerator.incrementAndGet()), attributes, Sets.newHashSet(DiscoveryNodeRole.MASTER_ROLE,
+            DiscoveryNodeRole.DATA_ROLE), Version.CURRENT);
     }
 }

docs/reference/cat/nodes.asciidoc

@@ -14,7 +14,7 @@ Might look like:
 [source,txt]
 --------------------------------------------------
 ip        heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name
-127.0.0.1           65          99  42    3.07                  mdi       *      mJw06l1
+127.0.0.1           65          99  42    3.07                  dim       *      mJw06l1
 --------------------------------------------------
 // TESTRESPONSE[s/3.07/(\\d+\\.\\d+( \\d+\\.\\d+ (\\d+\\.\\d+)?)?)?/]
 // TESTRESPONSE[s/65          99  42/\\d+ \\d+ \\d+/]

docs/reference/getting-started.asciidoc

@@ -330,7 +330,7 @@ And the response:
 [source,txt]
 --------------------------------------------------
 ip        heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name
-127.0.0.1           10           5   5    4.46                        mdi      *      PB2SGZY
+127.0.0.1           10           5   5    4.46                        dim      *      PB2SGZY
 --------------------------------------------------
 // TESTRESPONSE[s/10           5   5    4.46/\\d+ \\d+ \\d+ (\\d+\\.\\d+)? (\\d+\\.\\d+)? (\\d+\.\\d+)?/]
 // TESTRESPONSE[s/[*]/[*]/ s/PB2SGZY/.+/ non_json]

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

@@ -22,7 +22,7 @@
 import org.elasticsearch.action.FailedNodeException;
 import org.elasticsearch.action.support.nodes.BaseNodesResponse;
 import org.elasticsearch.cluster.ClusterName;
-import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -74,8 +74,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             }
 
             builder.startArray("roles");
-            for (DiscoveryNode.Role role : nodeInfo.getNode().getRoles()) {
-                builder.value(role.getRoleName());
+            for (DiscoveryNodeRole role : nodeInfo.getNode().getRoles()) {
+                builder.value(role.roleName());
             }
             builder.endArray();
 

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

@@ -22,10 +22,10 @@
 import org.elasticsearch.Version;
 import org.elasticsearch.action.support.nodes.BaseNodeResponse;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.xcontent.ToXContent.Params;
 import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.discovery.DiscoveryStats;
@@ -277,8 +277,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.field("ip", getNode().getAddress());
 
         builder.startArray("roles");
-        for (DiscoveryNode.Role role : getNode().getRoles()) {
-            builder.value(role.getRoleName());
+        for (DiscoveryNodeRole role : getNode().getRoles()) {
+            builder.value(role.roleName());
         }
         builder.endArray();
 

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java

@@ -23,6 +23,7 @@
 import org.elasticsearch.action.TaskOperationFailure;
 import org.elasticsearch.action.support.tasks.BaseTasksResponse;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
@@ -175,8 +176,8 @@ public XContentBuilder toXContentGroupedByNode(XContentBuilder builder, Params p
                 builder.field("ip", node.getAddress());
 
                 builder.startArray("roles");
-                for (DiscoveryNode.Role role : node.getRoles()) {
-                    builder.value(role.getRoleName());
+                for (DiscoveryNodeRole role : node.getRoles()) {
+                    builder.value(role.roleName());
                 }
                 builder.endArray();
 

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

@@ -21,11 +21,11 @@
 
 import com.carrotsearch.hppc.ObjectIntHashMap;
 import com.carrotsearch.hppc.cursors.ObjectIntCursor;
-
 import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.cluster.node.info.NodeInfo;
 import org.elasticsearch.action.admin.cluster.node.stats.NodeStats;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.network.NetworkModule;
@@ -49,6 +49,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.TreeMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public class ClusterStatsNodes implements ToXContentFragment {
@@ -186,27 +187,27 @@ public static class Counts implements ToXContentFragment {
         private final int total;
         private final Map<String, Integer> roles;
 
-        private Counts(List<NodeInfo> nodeInfos) {
-            this.roles = new HashMap<>();
-            for (DiscoveryNode.Role role : DiscoveryNode.Role.values()) {
-                this.roles.put(role.getRoleName(), 0);
+        private Counts(final List<NodeInfo> nodeInfos) {
+            // TODO: do we need to report zeros?
+            final Map<String, Integer> roles = new HashMap<>(DiscoveryNode.getPossibleRoleNames().size());
+            roles.put(COORDINATING_ONLY, 0);
+            for (final String possibleRoleName : DiscoveryNode.getPossibleRoleNames()) {
+                roles.put(possibleRoleName, 0);
             }
-            this.roles.put(COORDINATING_ONLY, 0);
 
             int total = 0;
-            for (NodeInfo nodeInfo : nodeInfos) {
+            for (final NodeInfo nodeInfo : nodeInfos) {
                 total++;
                 if (nodeInfo.getNode().getRoles().isEmpty()) {
-                    Integer count = roles.get(COORDINATING_ONLY);
-                    roles.put(COORDINATING_ONLY, ++count);
+                    roles.merge(COORDINATING_ONLY, 1, Integer::sum);
                 } else {
-                    for (DiscoveryNode.Role role : nodeInfo.getNode().getRoles()) {
-                        Integer count = roles.get(role.getRoleName());
-                        roles.put(role.getRoleName(), ++count);
+                    for (DiscoveryNodeRole role : nodeInfo.getNode().getRoles()) {
+                        roles.merge(role.roleName(), 1, Integer::sum);
                     }
                 }
             }
             this.total = total;
+            this.roles = Collections.unmodifiableMap(new HashMap<>(roles));
         }
 
         public int getTotal() {
@@ -225,7 +226,7 @@ static final class Fields {
         public XContentBuilder toXContent(XContentBuilder builder, Params params)
                 throws IOException {
             builder.field(Fields.TOTAL, total);
-            for (Map.Entry<String, Integer> entry : roles.entrySet()) {
+            for (Map.Entry<String, Integer> entry : new TreeMap<>(roles).entrySet()) {
                 builder.field(entry.getKey(), entry.getValue());
             }
             return builder;