KAFKA-8066; Always close the sensors in Selector.close() (#6402)

When shutting down the ReplicaFetcher thread, we may fail to unregister sensors in selector.close(). When that happened, we will fail to start up the ReplicaFetcherThread with the same fetch id again because of the IllegalArgumentException in sensor registration. This issue will cause constant URPs in the cluster because the ReplicaFetchterThread is gone.

This patch addresses this issue by introducing a try-finally block in selector.close() so that we will always unregister the sensors in shutting down ReplicaFetcherThreads.

Reviewers: Rajini Sivaram <rajinisivaram@googlemail.com>, Jason Gustafson <jason@confluent.io>

clients/src/main/java/org/apache/kafka/clients/ClientUtils.java

@@ -27,14 +27,12 @@ import org.apache.kafka.common.utils.Time;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.Closeable;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicReference;
 
 import static org.apache.kafka.common.utils.Utils.getHost;
 import static org.apache.kafka.common.utils.Utils.getPort;
@@ -91,17 +89,6 @@ public final class ClientUtils {
         return addresses;
     }
 
-    public static void closeQuietly(Closeable c, String name, AtomicReference<Throwable> firstException) {
-        if (c != null) {
-            try {
-                c.close();
-            } catch (Throwable t) {
-                firstException.compareAndSet(null, t);
-                log.error("Failed to close " + name, t);
-            }
-        }
-    }
-
     /**
      * @param config client configs
      * @return configured ChannelBuilder based on the configs.

clients/src/main/java/org/apache/kafka/clients/consumer/KafkaConsumer.java

@@ -2201,12 +2201,12 @@ public class KafkaConsumer<K, V> implements Consumer<K, V> {
             firstException.compareAndSet(null, t);
             log.error("Failed to close coordinator", t);
         }
-        ClientUtils.closeQuietly(fetcher, "fetcher", firstException);
-        ClientUtils.closeQuietly(interceptors, "consumer interceptors", firstException);
-        ClientUtils.closeQuietly(metrics, "consumer metrics", firstException);
-        ClientUtils.closeQuietly(client, "consumer network client", firstException);
-        ClientUtils.closeQuietly(keyDeserializer, "consumer key deserializer", firstException);
-        ClientUtils.closeQuietly(valueDeserializer, "consumer value deserializer", firstException);
+        Utils.closeQuietly(fetcher, "fetcher", firstException);
+        Utils.closeQuietly(interceptors, "consumer interceptors", firstException);
+        Utils.closeQuietly(metrics, "consumer metrics", firstException);
+        Utils.closeQuietly(client, "consumer network client", firstException);
+        Utils.closeQuietly(keyDeserializer, "consumer key deserializer", firstException);
+        Utils.closeQuietly(valueDeserializer, "consumer value deserializer", firstException);
         AppInfoParser.unregisterAppInfo(JMX_PREFIX, clientId, metrics);
         log.debug("Kafka consumer has been closed");
         Throwable exception = firstException.get();

clients/src/main/java/org/apache/kafka/clients/producer/KafkaProducer.java

@@ -67,6 +67,7 @@ import org.apache.kafka.common.utils.AppInfoParser;
 import org.apache.kafka.common.utils.KafkaThread;
 import org.apache.kafka.common.utils.LogContext;
 import org.apache.kafka.common.utils.Time;
+import org.apache.kafka.common.utils.Utils;
 import org.slf4j.Logger;
 
 import java.net.InetSocketAddress;
@@ -1188,11 +1189,11 @@ public class KafkaProducer<K, V> implements Producer<K, V> {
             }
         }
 
-        ClientUtils.closeQuietly(interceptors, "producer interceptors", firstException);
-        ClientUtils.closeQuietly(metrics, "producer metrics", firstException);
-        ClientUtils.closeQuietly(keySerializer, "producer keySerializer", firstException);
-        ClientUtils.closeQuietly(valueSerializer, "producer valueSerializer", firstException);
-        ClientUtils.closeQuietly(partitioner, "producer partitioner", firstException);
+        Utils.closeQuietly(interceptors, "producer interceptors", firstException);
+        Utils.closeQuietly(metrics, "producer metrics", firstException);
+        Utils.closeQuietly(keySerializer, "producer keySerializer", firstException);
+        Utils.closeQuietly(valueSerializer, "producer valueSerializer", firstException);
+        Utils.closeQuietly(partitioner, "producer partitioner", firstException);
         AppInfoParser.unregisterAppInfo(JMX_PREFIX, clientId, metrics);
         Throwable exception = firstException.get();
         if (exception != null && !swallowException) {

clients/src/main/java/org/apache/kafka/common/network/Selector.java

@@ -30,6 +30,7 @@ import org.apache.kafka.common.metrics.stats.SampledStat;
 import org.apache.kafka.common.metrics.stats.Total;
 import org.apache.kafka.common.utils.LogContext;
 import org.apache.kafka.common.utils.Time;
+import org.apache.kafka.common.utils.Utils;
 import org.slf4j.Logger;
 
 import java.io.IOException;
@@ -52,6 +53,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * A nioSelector interface for doing non-blocking multi-connection network I/O.
@@ -358,15 +360,24 @@ public class Selector implements Selectable, AutoCloseable {
     @Override
     public void close() {
         List<String> connections = new ArrayList<>(channels.keySet());
-        for (String id : connections)
-            close(id);
         try {
-            this.nioSelector.close();
-        } catch (IOException | SecurityException e) {
-            log.error("Exception closing nioSelector:", e);
+            for (String id : connections)
+                close(id);
+        } finally {
+            // If there is any exception thrown in close(id), we should still be able
+            // to close the remaining objects, especially the sensors because keeping
+            // the sensors may lead to failure to start up the ReplicaFetcherThread if
+            // the old sensors with the same names has not yet been cleaned up.
+            AtomicReference<Throwable> firstException = new AtomicReference<>();
+            Utils.closeQuietly(nioSelector, "nioSelector", firstException);
+            Utils.closeQuietly(sensors, "sensors", firstException);
+            Utils.closeQuietly(channelBuilder, "channelBuilder", firstException);
+            Throwable exception = firstException.get();
+            if (exception instanceof RuntimeException && !(exception instanceof SecurityException)) {
+                throw (RuntimeException) exception;
+            }
+
         }
-        sensors.close();
-        channelBuilder.close();
     }
 
     /**

clients/src/main/java/org/apache/kafka/common/utils/Utils.java

@@ -57,6 +57,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Properties;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -857,6 +858,18 @@ public final class Utils {
         }
     }
 
+    public static void closeQuietly(AutoCloseable closeable, String name, AtomicReference<Throwable> firstException) {
+        if (closeable != null) {
+            try {
+                closeable.close();
+            } catch (Throwable t) {
+                firstException.compareAndSet(null, t);
+                log.error("Failed to close {} with type {}", name, closeable.getClass().getName(), t);
+            }
+        }
+    }
+
+
     /**
      * A cheap way to deterministically convert a number to a positive value. When the input is
      * positive, the original value is returned. When the input number is negative, the returned

clients/src/test/java/org/apache/kafka/common/network/SelectorTest.java

@@ -59,6 +59,7 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
@@ -717,6 +718,26 @@ public class SelectorTest {
         assertNull(selector.lowestPriorityChannel());
     }
 
+    @Test
+    public void testMetricsCleanupOnSelectorClose() throws Exception {
+        Metrics metrics = new Metrics();
+        Selector selector = new ImmediatelyConnectingSelector(5000, metrics, time, "MetricGroup", channelBuilder, new LogContext()) {
+            @Override
+            public void close(String id) {
+                throw new RuntimeException();
+            }
+        };
+        assertTrue(metrics.metrics().size() > 1);
+        String id = "0";
+        selector.connect(id, new InetSocketAddress("localhost", server.port), BUFFER_SIZE, BUFFER_SIZE);
+
+        // Close the selector and ensure a RuntimeException has been throw
+        assertThrows(RuntimeException.class, selector::close);
+
+        // We should only have one remaining metric for kafka-metrics-count, which is a global metric
+        assertEquals(1, metrics.metrics().size());
+    }
+
 
     private String blockingRequest(String node, String s) throws IOException {
         selector.send(createSend(node, s));

connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/WorkerGroupMember.java

@@ -34,6 +34,7 @@ import org.apache.kafka.common.network.Selector;
 import org.apache.kafka.common.utils.AppInfoParser;
 import org.apache.kafka.common.utils.LogContext;
 import org.apache.kafka.common.utils.Time;
+import org.apache.kafka.common.utils.Utils;
 import org.apache.kafka.connect.storage.ConfigBackingStore;
 import org.apache.kafka.connect.util.ConnectorTaskId;
 import org.slf4j.Logger;
@@ -205,9 +206,9 @@ public class WorkerGroupMember {
         log.trace("Stopping the Connect group member.");
         AtomicReference<Throwable> firstException = new AtomicReference<>();
         this.stopped = true;
-        ClientUtils.closeQuietly(coordinator, "coordinator", firstException);
-        ClientUtils.closeQuietly(metrics, "consumer metrics", firstException);
-        ClientUtils.closeQuietly(client, "consumer network client", firstException);
+        Utils.closeQuietly(coordinator, "coordinator", firstException);
+        Utils.closeQuietly(metrics, "consumer metrics", firstException);
+        Utils.closeQuietly(client, "consumer network client", firstException);
         AppInfoParser.unregisterAppInfo(JMX_PREFIX, clientId, metrics);
         if (firstException.get() != null && !swallowException)
             throw new KafkaException("Failed to stop the Connect group member", firstException.get());