Close resources only if initialised to avoid rare case NPE

kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/IcebergSinkConfig.java

@@ -92,6 +92,7 @@ public class IcebergSinkConfig extends AbstractConfig {
   private static final String HADOOP_CONF_DIR_PROP = "iceberg.hadoop-conf-dir";
 
   private static final String NAME_PROP = "name";
+  private static final String TASK_ID = "task.id";
   private static final String BOOTSTRAP_SERVERS_PROP = "bootstrap.servers";
 
   private static final String DEFAULT_CATALOG_NAME = "iceberg";
@@ -101,6 +102,9 @@ public class IcebergSinkConfig extends AbstractConfig {
   public static final int SCHEMA_UPDATE_RETRIES = 2; // 3 total attempts
   public static final int CREATE_TABLE_RETRIES = 2; // 3 total attempts
 
+  private static final String COORDINATOR_EXECUTOR_KEEP_ALIVE_TIMEOUT_MS =
+      "iceberg.coordinator-executor-keep-alive-timeout-ms";
+
   @VisibleForTesting static final String COMMA_NO_PARENS_REGEX = ",(?![^()]*+\\))";
 
   public static final ConfigDef CONFIG_DEF = newConfigDef();
@@ -225,6 +229,12 @@ private static ConfigDef newConfigDef() {
         null,
         Importance.MEDIUM,
         "If specified, Hadoop config files in this directory will be loaded");
+    configDef.define(
+        COORDINATOR_EXECUTOR_KEEP_ALIVE_TIMEOUT_MS,
+        ConfigDef.Type.LONG,
+        120000L,
+        Importance.LOW,
+        "config to control coordinator executor keep alive time");
     return configDef;
   }
 
@@ -284,6 +294,10 @@ public String connectorName() {
     return originalProps.get(NAME_PROP);
   }
 
+  public String taskId() {
+    return originalProps.get(TASK_ID);
+  }
+
   public String transactionalSuffix() {
     // this is for internal use and is not part of the config definition...
     return originalProps.get(INTERNAL_TRANSACTIONAL_SUFFIX_PROP);
@@ -337,6 +351,10 @@ public String tablesDefaultPartitionBy() {
     return getString(TABLES_DEFAULT_PARTITION_BY);
   }
 
+  public long keepAliveTimeoutInMs() {
+    return getLong(COORDINATOR_EXECUTOR_KEEP_ALIVE_TIMEOUT_MS);
+  }
+
   public TableSinkConfig tableConfig(String tableName) {
     return tableConfigMap.computeIfAbsent(
         tableName,

kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/IcebergSinkConnector.java

@@ -55,6 +55,7 @@ public List<Map<String, String>> taskConfigs(int maxTasks) {
             i -> {
               Map<String, String> map = Maps.newHashMap(props);
               map.put(IcebergSinkConfig.INTERNAL_TRANSACTIONAL_SUFFIX_PROP, txnSuffix + i);
+              map.put("task.id", String.valueOf(i));
               return map;
             })
         .collect(Collectors.toList());

kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/channel/CommitterImpl.java

@@ -136,11 +136,23 @@ public void stop() {
 
   @Override
   public void close(Collection<TopicPartition> closedPartitions) {
+    if (!isInitialized.get()) {
+      LOG.warn("Unexpected close() call without resource initialization");
+      return;
+    }
     if (hasLeaderPartition(closedPartitions)) {
-      LOG.info("Committer lost leader partition. Stopping Coordinator.");
+      LOG.info(
+          "Committer {}-{} lost leader partition. Stopping Coordinator.",
+          config.connectorName(),
+          config.taskId());
       stopCoordinator();
     }
+    LOG.info("Stopping worker {}-{}.", config.connectorName(), config.taskId());
     stopWorker();
+    LOG.info(
+        "Seeking to last committed offsets for worker {}-{}.",
+        config.connectorName(),
+        config.taskId());
     KafkaUtils.seekToLastCommittedOffsets(context);
   }
 

kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/channel/Coordinator.java

@@ -28,6 +28,8 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -51,8 +53,8 @@
 import org.apache.iceberg.exceptions.NoSuchTableException;
 import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap;
 import org.apache.iceberg.relocated.com.google.common.collect.Maps;
+import org.apache.iceberg.relocated.com.google.common.util.concurrent.ThreadFactoryBuilder;
 import org.apache.iceberg.util.Tasks;
-import org.apache.iceberg.util.ThreadPools;
 import org.apache.kafka.clients.admin.MemberDescription;
 import org.apache.kafka.connect.errors.ConnectException;
 import org.apache.kafka.connect.sink.SinkTaskContext;
@@ -73,7 +75,6 @@ class Coordinator extends Channel {
   private final String snapshotOffsetsProp;
   private final ExecutorService exec;
   private final CommitState commitState;
-  private volatile boolean terminated;
 
   Coordinator(
       Catalog catalog,
@@ -91,7 +92,17 @@ class Coordinator extends Channel {
     this.snapshotOffsetsProp =
         String.format(
             "kafka.connect.offsets.%s.%s", config.controlTopic(), config.connectGroupId());
-    this.exec = ThreadPools.newFixedThreadPool("iceberg-committer", config.commitThreads());
+    this.exec =
+        new ThreadPoolExecutor(
+            config.commitThreads(),
+            config.commitThreads(),
+            config.keepAliveTimeoutInMs(),
+            TimeUnit.MILLISECONDS,
+            new LinkedBlockingQueue<>(),
+            new ThreadFactoryBuilder()
+                .setDaemon(true)
+                .setNameFormat("iceberg-committer" + "-%d")
+                .build());
     this.commitState = new CommitState(config);
   }
 
@@ -221,10 +232,6 @@ private void commitToTable(
             .filter(distinctByKey(ContentFile::location))
             .collect(Collectors.toList());
 
-    if (terminated) {
-      throw new ConnectException("Coordinator is terminated, commit aborted");
-    }
-
     if (dataFiles.isEmpty() && deleteFiles.isEmpty()) {
       LOG.info("Nothing to commit to table {}, skipping", tableIdentifier);
     } else {
@@ -304,10 +311,7 @@ private Map<Integer, Long> lastCommittedOffsetsForTable(Table table, String bran
   }
 
   void terminate() {
-    this.terminated = true;
-
     exec.shutdownNow();
-
     // wait for coordinator termination, else cause the sink task to fail
     try {
       if (!exec.awaitTermination(1, TimeUnit.MINUTES)) {
@@ -317,4 +321,10 @@ void terminate() {
       throw new ConnectException("Interrupted while waiting for coordinator shutdown", e);
     }
   }
+
+  @Override
+  public void stop() {
+    terminate();
+    super.stop();
+  }
 }

kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/channel/CoordinatorThread.java

@@ -64,6 +64,5 @@ boolean isTerminated() {
 
   void terminate() {
     this.terminated = true;
-    coordinator.terminate();
   }
 }