dpol1 commented on code in PR #3062:
URL: https://github.com/apache/hugegraph/pull/3062#discussion_r3457937601
##########
hugegraph-server/hugegraph-core/src/main/java/org/apache/hugegraph/meta/EtcdMetaDriver.java:
##########
@@ -314,9 +341,35 @@ public <T> void listen(String key, Consumer<T> consumer) {
@SuppressWarnings("unchecked")
@Override
public <T> void listenPrefix(String prefix, Consumer<T> consumer) {
- ByteSequence sequence = toByteSequence(prefix);
WatchOption option = WatchOption.newBuilder().isPrefix(true).build();
- this.client.getWatchClient().watch(sequence, option,
(Consumer<WatchResponse>) consumer);
+ this.watchKey(toByteSequence(prefix), option,
+ (Consumer<WatchResponse>) consumer);
+ }
+
+ /**
+ * Subscribe a self-healing watch. Unlike the bare {@code Consumer}
overload,
+ * this surfaces {@code onError}/{@code onCompleted}: when the underlying
+ * watch terminates (e.g. a transport reconnect drops the gRPC stream) it
+ * re-subscribes after a short backoff, so the listener is not silently
lost.
+ * Mirrors the re-subscribe behaviour PdMetaDriver already gets from
KvClient.
+ */
+ private void watchKey(ByteSequence key, WatchOption option,
+ Consumer<WatchResponse> consumer) {
+ Watch.Listener listener = Watch.listener(
+ consumer,
+ throwable -> this.scheduleReWatch(key, option, consumer,
throwable),
Review Comment:
Address by d2bd2a2
##########
hugegraph-server/hugegraph-core/src/main/java/org/apache/hugegraph/meta/EtcdMetaDriver.java:
##########
@@ -314,9 +341,35 @@ public <T> void listen(String key, Consumer<T> consumer) {
@SuppressWarnings("unchecked")
@Override
public <T> void listenPrefix(String prefix, Consumer<T> consumer) {
- ByteSequence sequence = toByteSequence(prefix);
WatchOption option = WatchOption.newBuilder().isPrefix(true).build();
- this.client.getWatchClient().watch(sequence, option,
(Consumer<WatchResponse>) consumer);
+ this.watchKey(toByteSequence(prefix), option,
+ (Consumer<WatchResponse>) consumer);
+ }
+
+ /**
+ * Subscribe a self-healing watch. Unlike the bare {@code Consumer}
overload,
+ * this surfaces {@code onError}/{@code onCompleted}: when the underlying
+ * watch terminates (e.g. a transport reconnect drops the gRPC stream) it
+ * re-subscribes after a short backoff, so the listener is not silently
lost.
+ * Mirrors the re-subscribe behaviour PdMetaDriver already gets from
KvClient.
+ */
+ private void watchKey(ByteSequence key, WatchOption option,
+ Consumer<WatchResponse> consumer) {
+ Watch.Listener listener = Watch.listener(
+ consumer,
+ throwable -> this.scheduleReWatch(key, option, consumer,
throwable),
+ () -> this.scheduleReWatch(key, option, consumer, null));
+ // Watcher intentionally not closed: process-lifetime watch, recreated
+ // on self-heal; the prior watcher's stream has already terminated.
+ this.client.getWatchClient().watch(key, option, listener);
+ }
+ private void scheduleReWatch(ByteSequence key, WatchOption option,
+ Consumer<WatchResponse> consumer,
+ Throwable cause) {
+ LOG.warn("etcd meta watch dropped, re-subscribing", cause);
+ this.reWatchExecutor.schedule(
Review Comment:
Address by d2bd2a2
##########
hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/meta/EtcdMetaDriverTest.java:
##########
@@ -0,0 +1,115 @@
+/*
+ * 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.hugegraph.meta;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.apache.hugegraph.testutil.Assert;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mockito;
+
+import io.etcd.jetcd.ByteSequence;
+import io.etcd.jetcd.Client;
+import io.etcd.jetcd.Watch;
+import io.etcd.jetcd.options.WatchOption;
+import io.etcd.jetcd.watch.WatchResponse;
+
+/**
+ * Unit tests for {@link EtcdMetaDriver}'s self-healing watch: a dropped watch
+ * (onError / onCompleted) must be re-subscribed so the listener is not
silently
+ * lost after a transport reconnect (issue #3036). Uses a mock jetcd
+ * {@link Client} via the package-private test constructor; no live etcd
needed.
+ */
+public class EtcdMetaDriverTest {
+
+ @Test
+ public void testListenReSubscribesOnError() {
+ Watch watch = Mockito.mock(Watch.class);
+ EtcdMetaDriver driver = newDriver(watch);
+
+ driver.listen("k", response -> { });
+ captureListener(watch).onError(new RuntimeException("watch dropped"));
+
+ // The watch terminated, so the driver must re-subscribe: a second
+ // watch() call lands once the (0ms) backoff task runs.
+ Mockito.verify(watch, Mockito.timeout(2000).times(2))
+ .watch(Mockito.any(ByteSequence.class),
+ Mockito.any(WatchOption.class),
+ Mockito.any(Watch.Listener.class));
+ }
+
+ @Test
+ public void testListenReSubscribesOnCompleted() {
+ Watch watch = Mockito.mock(Watch.class);
+ EtcdMetaDriver driver = newDriver(watch);
+
+ driver.listen("k", response -> { });
+ captureListener(watch).onCompleted();
+
+ Mockito.verify(watch, Mockito.timeout(2000).times(2))
+ .watch(Mockito.any(ByteSequence.class),
+ Mockito.any(WatchOption.class),
+ Mockito.any(Watch.Listener.class));
+ }
+
+ @Test
+ public void testListenPrefixReSubscribesOnError() {
+ Watch watch = Mockito.mock(Watch.class);
Review Comment:
Address by d2bd2a2
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