KAFKA-17292: Introduce share coordinator protocol config (#16847)

Add the "share" group coordinator rebalance protocol as the way to enable KIP-932. It is also necessary to turn on the new group coordinator.

Reviewers:  Apoorv Mittal <apoorvmittal10@gmail.com>,  Manikumar Reddy <manikumar.reddy@gmail.com>

core/src/main/scala/kafka/server/KafkaConfig.scala

@@ -579,6 +579,14 @@ class KafkaConfig private(doLog: Boolean, val props: util.Map[_, _])
       warn(s"The new '${GroupType.CONSUMER}' rebalance protocol is enabled along with the new group coordinator. " +
         "This is part of the preview of KIP-848 and MUST NOT be used in production.")
     }
+    if (protocols.contains(GroupType.SHARE)) {
+      // The CONSUMER protocol enables the new group coordinator, and that's a prerequisite for share groups.
+      if (!protocols.contains(GroupType.CONSUMER)) {
+        throw new ConfigException(s"Enabling the new '${GroupType.SHARE}' rebalance protocol requires '${GroupType.CONSUMER}' to be enabled also.")
+      }
+      warn(s"Share groups and the new '${GroupType.SHARE}' rebalance protocol are enabled. " +
+        "This is part of the early access of KIP-932 and MUST NOT be used in production.")
+    }
     protocols
   }
   // The new group coordinator is enabled in two cases: 1) The internal configuration to enable

core/src/test/scala/unit/kafka/server/KafkaConfigTest.scala

@@ -1941,7 +1941,7 @@ class KafkaConfigTest {
     // Setting KRaft's properties.
     props.putAll(kraftProps())
 
-    // Only classic and consumer are supported.
+    // Only classic, consumer and share are supported.
     props.put(GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG, "foo")
     assertThrows(classOf[ConfigException], () => KafkaConfig.fromProps(props))
 
@@ -1951,9 +1951,21 @@ class KafkaConfigTest {
 
     // This is OK.
     props.put(GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG, "classic,consumer")
-    val config = KafkaConfig.fromProps(props)
+    var config = KafkaConfig.fromProps(props)
     assertEquals(Set(GroupType.CLASSIC, GroupType.CONSUMER), config.groupCoordinatorRebalanceProtocols)
     assertTrue(config.isNewGroupCoordinatorEnabled)
+    assertFalse(config.shareGroupConfig.isShareGroupEnabled)
+
+    // This is OK.
+    props.put(GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG, "classic,consumer,share")
+    config = KafkaConfig.fromProps(props)
+    assertEquals(Set(GroupType.CLASSIC, GroupType.CONSUMER, GroupType.SHARE), config.groupCoordinatorRebalanceProtocols)
+    assertTrue(config.isNewGroupCoordinatorEnabled)
+    assertTrue(config.shareGroupConfig.isShareGroupEnabled)
+
+    // If you set share, you must also set consumer.
+    props.put(GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG, "classic,share")
+    assertThrows(classOf[ConfigException], () => KafkaConfig.fromProps(props))
   }
 
   @Test

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorConfig.java

@@ -76,7 +76,8 @@ public class GroupCoordinatorConfig {
     public static final String GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG = "group.coordinator.rebalance.protocols";
     public static final String GROUP_COORDINATOR_REBALANCE_PROTOCOLS_DOC = "The list of enabled rebalance protocols. Supported protocols: " +
             Arrays.stream(Group.GroupType.values()).map(Group.GroupType::toString).collect(Collectors.joining(",")) + ". " +
-            "The " + Group.GroupType.CONSUMER + " rebalance protocol is in early access and therefore must not be used in production.";
+            "The " + Group.GroupType.CONSUMER + " rebalance protocol is in preview and therefore must not be used in production. " +
+            "The " + Group.GroupType.SHARE + " rebalance protocol is in early access and therefore must not be used in production.";
     public static final List<String> GROUP_COORDINATOR_REBALANCE_PROTOCOLS_DEFAULT = Collections.singletonList(Group.GroupType.CLASSIC.toString());
     public static final String GROUP_COORDINATOR_APPEND_LINGER_MS_CONFIG = "group.coordinator.append.linger.ms";
     public static final String GROUP_COORDINATOR_APPEND_LINGER_MS_DOC = "The duration in milliseconds that the coordinator will " +

server/src/main/java/org/apache/kafka/server/config/ShareGroupConfig.java

@@ -16,9 +16,14 @@
  */
 package org.apache.kafka.server.config;
 
+import org.apache.kafka.common.GroupType;
 import org.apache.kafka.common.config.AbstractConfig;
 import org.apache.kafka.common.config.ConfigDef;
 import org.apache.kafka.common.utils.Utils;
+import org.apache.kafka.coordinator.group.GroupCoordinatorConfig;
+
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.apache.kafka.common.config.ConfigDef.Importance.MEDIUM;
 import static org.apache.kafka.common.config.ConfigDef.Range.between;
@@ -76,7 +81,12 @@ public class ShareGroupConfig {
     private final int shareGroupMinRecordLockDurationMs;
 
     public ShareGroupConfig(AbstractConfig config) {
-        isShareGroupEnabled = config.getBoolean(ShareGroupConfig.SHARE_GROUP_ENABLE_CONFIG);
+        // Share groups are enabled in two cases: 1) The internal configuration to enable it is
+        // explicitly set; or 2) the share rebalance protocol is enabled.
+        Set<String> protocols = config.getList(GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG)
+            .stream().map(String::toUpperCase).collect(Collectors.toSet());
+        isShareGroupEnabled = config.getBoolean(ShareGroupConfig.SHARE_GROUP_ENABLE_CONFIG) ||
+            protocols.contains(GroupType.SHARE.name());
         shareGroupPartitionMaxRecordLocks = config.getInt(ShareGroupConfig.SHARE_GROUP_PARTITION_MAX_RECORD_LOCKS_CONFIG);
         shareGroupDeliveryCountLimit = config.getInt(ShareGroupConfig.SHARE_GROUP_DELIVERY_COUNT_LIMIT_CONFIG);
         shareGroupMaxGroups = config.getShort(ShareGroupConfig.SHARE_GROUP_MAX_GROUPS_CONFIG);