Use Helidon gRPC client in Config Etcd module (#9674)

* Switches from Netty to our gRPC client.
* Updates problematic IT tests and constrains its scope to run only with V3 servers. V2 support is deprecated and marked for removal.
---------
Signed-off-by: Santiago Pericas-Geertsen <[email protected]>

Author: spericas

config/etcd/pom.xml

@@ -49,7 +49,10 @@
             <groupId>io.helidon.common</groupId>
             <artifactId>helidon-common-media-type</artifactId>
         </dependency>
-
+        <dependency>
+            <groupId>io.helidon.webclient</groupId>
+            <artifactId>helidon-webclient-grpc</artifactId>
+        </dependency>
         <!-- etcd v2 -->
         <dependency>
             <groupId>org.mousio</groupId>
@@ -60,11 +63,6 @@
             <groupId>io.grpc</groupId>
             <artifactId>grpc-api</artifactId>
         </dependency>
-        <dependency>
-            <groupId>io.grpc</groupId>
-            <artifactId>grpc-netty</artifactId>
-            <scope>runtime</scope>
-        </dependency>
         <dependency>
             <groupId>io.grpc</groupId>
             <artifactId>grpc-protobuf</artifactId>
@@ -136,21 +134,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <systemPropertyVariables>
-                        <property>
-                            <!-- on big machines (e.g. 52 cores hyperthreaded)
-                             this failed with too many open files
-                             -->
-                            <name>io.netty.eventLoopThreads</name>
-                            <value>2</value>
-                        </property>
-                    </systemPropertyVariables>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>build-helper-maven-plugin</artifactId>

config/etcd/src/main/java/io/helidon/config/etcd/internal/client/v2/EtcdV2Client.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -55,7 +55,7 @@ public class EtcdV2Client implements EtcdClient {
      *
      * @deprecated
      */
-    EtcdV2Client(URI... uris) {
+    public EtcdV2Client(URI... uris) {
         etcd = new mousio.etcd4j.EtcdClient(uris);
         etcd.setRetryHandler(new RetryWithTimeout(100, 2000));
     }

config/etcd/src/main/java/io/helidon/config/etcd/internal/client/v3/EtcdV3Client.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,8 +22,8 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.Flow;
 import java.util.concurrent.SubmissionPublisher;
-import java.util.concurrent.TimeUnit;
 
+import io.helidon.common.tls.Tls;
 import io.helidon.config.etcd.internal.client.EtcdClient;
 import io.helidon.config.etcd.internal.client.EtcdClientException;
 import io.helidon.config.etcd.internal.client.proto.KVGrpc;
@@ -34,23 +34,20 @@
 import io.helidon.config.etcd.internal.client.proto.WatchGrpc;
 import io.helidon.config.etcd.internal.client.proto.WatchRequest;
 import io.helidon.config.etcd.internal.client.proto.WatchResponse;
+import io.helidon.webclient.grpc.GrpcClient;
 
 import com.google.protobuf.ByteString;
-import io.grpc.ManagedChannel;
-import io.grpc.ManagedChannelBuilder;
 import io.grpc.StatusRuntimeException;
 import io.grpc.stub.StreamObserver;
 
 /**
  * Etcd API v3 client.
  */
 public class EtcdV3Client implements EtcdClient {
-
-    private static final System.Logger LOGGER = System.getLogger(EtcdV3Client.class.getName());
+    private static final Tls DISABLE_TLS = Tls.builder().enabled(false).build();
 
     private final Map<String, SubmissionPublisher<Long>> publishers = new ConcurrentHashMap<>();
 
-    private final ManagedChannel channel;
     private final KVGrpc.KVBlockingStub kvStub;
     private final WatchGrpc.WatchStub watchStub;
 
@@ -64,11 +61,12 @@ public EtcdV3Client(URI... uris) {
             throw new IllegalArgumentException("EtcdV3Client only supports a single URI");
         }
         URI uri = uris[0];
-        ManagedChannelBuilder mcb = ManagedChannelBuilder.forAddress(uri.getHost(), uri.getPort());
-        this.channel = mcb.usePlaintext().build();
-
-        kvStub = KVGrpc.newBlockingStub(channel);
-        watchStub = WatchGrpc.newStub(channel);
+        GrpcClient grpcClient = GrpcClient.builder()
+                .baseUri(uri)
+                .tls(DISABLE_TLS)       // must explicitly disable it
+                .build();
+        kvStub = KVGrpc.newBlockingStub(grpcClient.channel());
+        watchStub = WatchGrpc.newStub(grpcClient.channel());
     }
 
     @Override
@@ -140,16 +138,7 @@ public Flow.Publisher<Long> watch(String key) throws EtcdClientException {
     }
 
     @Override
-    public void close() throws EtcdClientException {
+    public void close() {
         publishers.values().forEach(SubmissionPublisher::close);
-        if (!channel.isShutdown() && !channel.isTerminated()) {
-            try {
-                channel.awaitTermination(1, TimeUnit.SECONDS);
-            } catch (InterruptedException e) {
-                LOGGER.log(System.Logger.Level.INFO, "Error closing gRPC channel, reason: " + e.getLocalizedMessage(), e);
-            } finally {
-                channel.shutdown();
-            }
-        }
     }
 }

config/etcd/src/main/java/module-info.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@
     requires io.grpc.stub;
     requires io.helidon.common.media.type;
     requires io.helidon.common;
+    requires io.helidon.webclient.grpc;
 
     requires static java.annotation;
 

config/etcd/src/test/java/io/helidon/config/etcd/EtcdConfigSourceIT.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2022 Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,29 +29,27 @@
 import io.helidon.config.etcd.internal.client.EtcdClient;
 import io.helidon.config.hocon.HoconConfigParser;
 
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.EnumSource;
+import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.core.Is.is;
 
 /**
- * Tests {@link EtcdConfigSource} with both version, {@link EtcdApi#v2} and {@link EtcdApi#v3}.
+ * Integration test for {@link EtcdConfigSource} using {@link EtcdApi#v3}.
  */
 public class EtcdConfigSourceIT {
 
     private static final URI DEFAULT_URI = URI.create("http://localhost:2379");
 
-    @ParameterizedTest
-    @EnumSource(EtcdApi.class)
-    public void testConfig(EtcdApi version) throws Exception {
-        putConfiguration(version, "/application.conf");
+    @Test
+    public void testConfig() throws Exception {
+        putConfiguration("/application.conf");
         Config config = Config.builder()
                 .sources(EtcdConfigSource.builder()
                                  .uri(DEFAULT_URI)
                                  .key("configuration")
-                                 .api(version)
+                                 .api(EtcdApi.v3)
                                  .mediaType(MediaTypes.APPLICATION_HOCON)
                                  .build())
                 .addParser(HoconConfigParser.create())
@@ -60,15 +58,14 @@ public void testConfig(EtcdApi version) throws Exception {
         assertThat(config.get("security").asNodeList().get(), hasSize(1));
     }
 
-    @ParameterizedTest
-    @EnumSource(EtcdApi.class)
-    public void testConfigChanges(EtcdApi version) throws Exception {
-        putConfiguration(version, "/application.conf");
+    @Test
+    public void testConfigChanges() throws Exception {
+        putConfiguration("/application.conf");
         Config config = Config.builder()
                 .sources(EtcdConfigSource.builder()
                                  .uri(DEFAULT_URI)
                                  .key("configuration")
-                                 .api(version)
+                                 .api(EtcdApi.v3)
                                  .mediaType(MediaTypes.APPLICATION_HOCON)
                                  .changeWatcher(EtcdWatcher.create())
                                  .build())
@@ -77,27 +74,23 @@ public void testConfigChanges(EtcdApi version) throws Exception {
 
         assertThat(config.get("security").asNodeList().get(), hasSize(1));
 
-        CountDownLatch initLatch = new CountDownLatch(1);
         CountDownLatch nextLatch = new CountDownLatch(3);
+        config.onChange(it -> nextLatch.countDown());
 
-        config.onChange(it -> initLatch.countDown());
-
-        assertThat(initLatch.await(1, TimeUnit.SECONDS), is(true));
-
-        putConfiguration(version, "/application2.conf");
+        putConfiguration("/application2.conf");
         TimeUnit.MILLISECONDS.sleep(10);
-        putConfiguration(version, "/application3.conf");
+        putConfiguration("/application3.conf");
         TimeUnit.MILLISECONDS.sleep(10);
-        putConfiguration(version, "/application4.conf");
+        putConfiguration("/application4.conf");
 
         assertThat(nextLatch.await(20, TimeUnit.SECONDS), is(true));
     }
 
-    private static void putConfiguration(EtcdApi version, String resourcePath) throws Exception {
-        EtcdClient etcd = version.clientFactory().createClient(DEFAULT_URI);
-
+    private static void putConfiguration(String resourcePath) throws Exception {
+        EtcdClient etcd = EtcdApi.v3.clientFactory().createClient(DEFAULT_URI);
         File file = new File(EtcdConfigSourceIT.class.getResource(resourcePath).getFile());
-        etcd.put("configuration", String.join("\n", Files.readAllLines(file.toPath(), Charset.defaultCharset())));
+        etcd.put("configuration", String.join("\n",
+                Files.readAllLines(file.toPath(), Charset.defaultCharset())));
         etcd.close();
     }
 }

config/etcd/src/test/java/io/helidon/config/etcd/client/EtcdClientIT.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2021 Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,22 +18,17 @@
 
 import java.lang.reflect.InvocationTargetException;
 import java.net.URI;
-import java.util.List;
 import java.util.Random;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Flow;
 import java.util.concurrent.TimeUnit;
-import java.util.stream.Stream;
 
 import io.helidon.config.etcd.internal.client.EtcdClient;
 import io.helidon.config.etcd.internal.client.EtcdClientException;
-import io.helidon.config.etcd.internal.client.v2.EtcdV2Client;
 import io.helidon.config.etcd.internal.client.v3.EtcdV3Client;
 
 import org.hamcrest.core.Is;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -47,34 +42,26 @@ public class EtcdClientIT {
 
     private static final URI uri = URI.create("http://localhost:2379");
 
-    private static Stream<Class<? extends EtcdClient>> clients() {
-        return List.of(EtcdV2Client.class, EtcdV3Client.class).stream();
-    }
-
-    @ParameterizedTest
-    @MethodSource("clients")
-    public <T extends EtcdClient> void testPutGet(Class<T> clientClass) throws EtcdClientException {
-        runTest(clientClass, etcdClient -> {
+    @Test
+    public void testPutGet() {
+        runTest(etcdClient -> {
             etcdClient.put("key", "value");
             String result = etcdClient.get("key");
             assertThat(result, is("value"));
-            
         });
     }
-    
-    @ParameterizedTest
-    @MethodSource("clients")
-    public <T extends EtcdClient> void testGetNonExistingKey(Class<T> clientClass) throws EtcdClientException {
-        runTest(clientClass, etcdClient -> {
+
+    @Test
+    public void testGetNonExistingKey()  {
+        runTest(etcdClient -> {
             String result = etcdClient.get("non-existing-key");
             assertThat(result, nullValue());
         });
     }
 
-    @ParameterizedTest
-    @MethodSource("clients")
-    public <T extends EtcdClient> void testWatchNewKey(Class<T> clientClass) throws EtcdClientException, ExecutionException, InterruptedException {
-        runTest(clientClass, etcdClient -> {
+    @Test
+    public void testWatchNewKey() {
+        runTest(etcdClient -> {
             final String key = "key#" + new Random().nextLong();
             final String finalValue = "new value";
 
@@ -115,10 +102,9 @@ public void onComplete() {
         });
     }
 
-    @ParameterizedTest
-    @MethodSource("clients")
-    public <T extends EtcdClient> void testWatchValueChanges(Class<T> clientClass) throws EtcdClientException, ExecutionException, InterruptedException {
-        runTest(clientClass, etcdClient -> {
+    @Test
+    public void testWatchValueChanges() {
+        runTest(etcdClient -> {
             final String key = "key";
 
             etcdClient.put(key, "any value to change (just to be sure there is not already set to the final value");
@@ -166,14 +152,14 @@ public void onComplete() {
      */
     @FunctionalInterface
     private interface EtcdClientConsumer {
-        public void accept(EtcdClient t) throws EtcdClientException, InterruptedException;
+        void accept(EtcdClient t) throws EtcdClientException, InterruptedException;
     }
 
-    private <T extends EtcdClient> void runTest(
-            Class<T> clientClass,
-            EtcdClientConsumer test) throws EtcdClientException {
+    private <T extends EtcdClient> void runTest(EtcdClientConsumer test) {
         try {
-            try (EtcdClient etcdClient = clientClass.getDeclaredConstructor(URI.class).newInstance(uri)) {
+            URI[] uris = new URI[] {uri};
+            try (EtcdClient etcdClient = EtcdV3Client.class.getDeclaredConstructor(URI[].class)
+                    .newInstance(new Object[] {uris})) {
                 test.accept(etcdClient);
             } catch (EtcdClientException ex) {
                 fail(ex);