KAFKA-17896: Admin.describeClassicGroups

clients/src/main/java/org/apache/kafka/clients/admin/Admin.java

@@ -1844,6 +1844,28 @@ default ListShareGroupsResult listShareGroups() {
         return listShareGroups(new ListShareGroupsOptions());
     }
 
+    /**
+     * Describe some classic groups in the cluster.
+     *
+     * @param groupIds The IDs of the groups to describe.
+     * @param options  The options to use when describing the groups.
+     * @return The DescribeClassicGroupsResult.
+     */
+    DescribeClassicGroupsResult describeClassicGroups(Collection<String> groupIds,
+                                                      DescribeClassicGroupsOptions options);
+
+    /**
+     * Describe some classic groups in the cluster, with the default options.
+     * <p>
+     * This is a convenience method for {@link #describeClassicGroups(Collection, DescribeClassicGroupsOptions)}
+     * with default options. See the overload for more details.
+     *
+     * @param groupIds The IDs of the groups to describe.
+     * @return The DescribeClassicGroupsResult.
+     */
+    default DescribeClassicGroupsResult describeClassicGroups(Collection<String> groupIds) {
+        return describeClassicGroups(groupIds, new DescribeClassicGroupsOptions());
+    }
 
     /**
      * Add the provided application metric for subscription.

clients/src/main/java/org/apache/kafka/clients/admin/ClassicGroupDescription.java

@@ -0,0 +1,155 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.clients.admin;
+
+import org.apache.kafka.common.ClassicGroupState;
+import org.apache.kafka.common.Node;
+import org.apache.kafka.common.acl.AclOperation;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * A detailed description of a single classic group in the cluster.
+ */
+public class ClassicGroupDescription {
+    private final String groupId;
+    private final String protocol;
+    private final String protocolData;
+    private final Collection<MemberDescription> members;
+    private final ClassicGroupState state;
+    private final Node coordinator;
+    private final Set<AclOperation> authorizedOperations;
+
+    public ClassicGroupDescription(String groupId,
+                                   String protocol,
+                                   String protocolData,
+                                   Collection<MemberDescription> members,
+                                   ClassicGroupState state,
+                                   Node coordinator) {
+        this(groupId, protocol, protocolData, members, state, coordinator, Set.of());
+    }
+
+    public ClassicGroupDescription(String groupId,
+                                   String protocol,
+                                   String protocolData,
+                                   Collection<MemberDescription> members,
+                                   ClassicGroupState state,
+                                   Node coordinator,
+                                   Set<AclOperation> authorizedOperations) {
+        this.groupId = groupId == null ? "" : groupId;
+        this.protocol = protocol;
+        this.protocolData = protocolData == null ? "" : protocolData;
+        this.members = members == null ? List.of() : List.copyOf(members);
+        this.state = state;
+        this.coordinator = coordinator;
+        this.authorizedOperations = authorizedOperations;
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        final ClassicGroupDescription that = (ClassicGroupDescription) o;
+        return Objects.equals(groupId, that.groupId) &&
+            Objects.equals(protocol, that.protocol) &&
+            Objects.equals(protocolData, that.protocolData) &&
+            Objects.equals(members, that.members) &&
+            state == that.state &&
+            Objects.equals(coordinator, that.coordinator) &&
+            Objects.equals(authorizedOperations, that.authorizedOperations);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(groupId, protocol, protocolData, members, state, coordinator, authorizedOperations);
+    }
+
+    /**
+     * The id of the classic group.
+     */
+    public String groupId() {
+        return groupId;
+    }
+
+    /**
+     * The group protocol type.
+     */
+    public String protocol() {
+        return protocol;
+    }
+
+    /**
+     * The group protocol data. The meaning depends on the group protocol type.
+     * For a classic consumer group, this is the partition assignor name.
+     * For a classic connect group, this indicates which Connect protocols are enabled.
+     */
+    public String protocolData() {
+        return protocolData;
+    }
+
+    /**
+     * If the group is a simple consumer group or not.
+     */
+    public boolean isSimpleConsumerGroup() {
+        return protocol.isEmpty();
+    }
+
+    /**
+     * A list of the members of the classic group.
+     */
+    public Collection<MemberDescription> members() {
+        return members;
+    }
+
+    /**
+     * The classic group state, or UNKNOWN if the state is too new for us to parse.
+     */
+    public ClassicGroupState state() {
+        return state;
+    }
+
+    /**
+     * The classic group coordinator, or null if the coordinator is not known.
+     */
+    public Node coordinator() {
+        return coordinator;
+    }
+
+    /**
+     * authorizedOperations for this group, or null if that information is not known.
+     */
+    public  Set<AclOperation> authorizedOperations() {
+        return authorizedOperations;
+    }
+
+    @Override
+    public String toString() {
+        return "(groupId=" + groupId +
+            ", protocol='" + protocol + '\'' +
+            ", protocolData=" + protocolData +
+            ", members=" + members.stream().map(MemberDescription::toString).collect(Collectors.joining(",")) +
+            ", state=" + state +
+            ", coordinator=" + coordinator +
+            ", authorizedOperations=" + authorizedOperations +
+            ")";
+    }
+}

clients/src/main/java/org/apache/kafka/clients/admin/DescribeClassicGroupsOptions.java

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.clients.admin;
+
+import org.apache.kafka.common.annotation.InterfaceStability;
+
+import java.util.Collection;
+
+/**
+ * Options for {@link Admin#describeClassicGroups(Collection, DescribeClassicGroupsOptions)}.
+ * <p>
+ * The API of this class is evolving, see {@link Admin} for details.
+ */
+@InterfaceStability.Evolving
+public class DescribeClassicGroupsOptions extends AbstractOptions<DescribeClassicGroupsOptions> {
+    private boolean includeAuthorizedOperations;
+
+    public DescribeClassicGroupsOptions includeAuthorizedOperations(boolean includeAuthorizedOperations) {
+        this.includeAuthorizedOperations = includeAuthorizedOperations;
+        return this;
+    }
+
+    public boolean includeAuthorizedOperations() {
+        return includeAuthorizedOperations;
+    }
+}

clients/src/main/java/org/apache/kafka/clients/admin/DescribeClassicGroupsResult.java

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.clients.admin;
+
+import org.apache.kafka.common.KafkaFuture;
+import org.apache.kafka.common.annotation.InterfaceStability;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+
+
+/**
+ * The result of the {@link Admin#describeClassicGroups(Collection, DescribeClassicGroupsOptions)}} call.
+ * <p>
+ * The API of this class is evolving, see {@link Admin} for details.
+ */
+@InterfaceStability.Evolving
+public class DescribeClassicGroupsResult {
+
+    private final Map<String, KafkaFuture<ClassicGroupDescription>> futures;
+
+    public DescribeClassicGroupsResult(final Map<String, KafkaFuture<ClassicGroupDescription>> futures) {
+        this.futures = futures;
+    }
+
+    /**
+     * Return a map from group id to futures which yield group descriptions.
+     */
+    public Map<String, KafkaFuture<ClassicGroupDescription>> describedGroups() {
+        return new HashMap<>(futures);
+    }
+
+    /**
+     * Return a future which yields all ClassicGroupDescription objects, if all the describes succeed.
+     */
+    public KafkaFuture<Map<String, ClassicGroupDescription>> all() {
+        return KafkaFuture.allOf(futures.values().toArray(new KafkaFuture[0])).thenApply(
+            nil -> {
+                Map<String, ClassicGroupDescription> descriptions = new HashMap<>(futures.size());
+                futures.forEach((key, future) -> {
+                    try {
+                        descriptions.put(key, future.get());
+                    } catch (InterruptedException | ExecutionException e) {
+                        // This should be unreachable, since the KafkaFuture#allOf already ensured
+                        // that all of the futures completed successfully.
+                        throw new RuntimeException(e);
+                    }
+                });
+                return descriptions;
+            });
+    }
+}

clients/src/main/java/org/apache/kafka/clients/admin/ForwardingAdmin.java

@@ -314,6 +314,11 @@ public ListGroupsResult listGroups(ListGroupsOptions options) {
         return delegate.listGroups(options);
     }
 
+    @Override
+    public DescribeClassicGroupsResult describeClassicGroups(Collection<String> groupIds, DescribeClassicGroupsOptions options) {
+        return delegate.describeClassicGroups(groupIds, options);
+    }
+
     @Override
     public void registerMetricForSubscription(KafkaMetric metric) {
         throw new UnsupportedOperationException();

clients/src/main/java/org/apache/kafka/clients/admin/KafkaAdminClient.java

@@ -49,6 +49,7 @@
 import org.apache.kafka.clients.admin.internals.DeleteConsumerGroupOffsetsHandler;
 import org.apache.kafka.clients.admin.internals.DeleteConsumerGroupsHandler;
 import org.apache.kafka.clients.admin.internals.DeleteRecordsHandler;
+import org.apache.kafka.clients.admin.internals.DescribeClassicGroupsHandler;
 import org.apache.kafka.clients.admin.internals.DescribeConsumerGroupsHandler;
 import org.apache.kafka.clients.admin.internals.DescribeProducersHandler;
 import org.apache.kafka.clients.admin.internals.DescribeShareGroupsHandler;
@@ -3952,6 +3953,17 @@ void handleFailure(Throwable throwable) {
         return new ListShareGroupsResult(all);
     }
 
+    @Override
+    public DescribeClassicGroupsResult describeClassicGroups(final Collection<String> groupIds,
+                                                             final DescribeClassicGroupsOptions options) {
+        SimpleAdminApiFuture<CoordinatorKey, ClassicGroupDescription> future =
+            DescribeClassicGroupsHandler.newFuture(groupIds);
+        DescribeClassicGroupsHandler handler = new DescribeClassicGroupsHandler(options.includeAuthorizedOperations(), logContext);
+        invokeDriver(handler, future, options.timeoutMs);
+        return new DescribeClassicGroupsResult(future.all().entrySet().stream()
+            .collect(Collectors.toMap(entry -> entry.getKey().idValue, Map.Entry::getValue)));
+    }
+
     @Override
     public Map<MetricName, ? extends Metric> metrics() {
         return Collections.unmodifiableMap(this.metrics.metrics());