Moves ClientUriSupplier as a top-level class. Adds new test showing h…

…ow to retry and advance to next URI using a supplier.

webclient/grpc/src/main/java/io/helidon/webclient/grpc/ClientUriSupplier.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2024 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.
+ * 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 io.helidon.webclient.grpc;
+
+import java.util.Iterator;
+
+import io.helidon.webclient.api.ClientUri;
+
+/**
+ * Interface implemented by all client URI suppliers.
+ */
+public interface ClientUriSupplier extends Iterator<ClientUri>, Iterable<ClientUri> {
+
+    @Override
+    default Iterator<ClientUri> iterator() {
+        return this;
+    }
+}

webclient/grpc/src/main/java/io/helidon/webclient/grpc/ClientUriSuppliers.java

@@ -29,12 +29,6 @@
  */
 public class ClientUriSuppliers {
 
-    /**
-     * Interfaces implemented by all client URI suppliers.
-     */
-    public interface ClientUriSupplier extends Iterator<ClientUri> {
-    }
-
     /**
      * Supplies an iterator that returns URIs chosen in order from
      * first to last.

webclient/grpc/src/main/java/io/helidon/webclient/grpc/GrpcBaseClientCall.java

@@ -73,7 +73,7 @@ abstract class GrpcBaseClientCall<ReqT, ResT> extends ClientCall<ReqT, ResT> {
     private final Duration pollWaitTime;
     private final boolean abortPollTimeExpired;
     private final Duration heartbeatPeriod;
-    private final ClientUriSuppliers.ClientUriSupplier clientUriSupplier;
+    private final ClientUriSupplier clientUriSupplier;
 
     private final MethodDescriptor.Marshaller<ReqT> requestMarshaller;
     private final MethodDescriptor.Marshaller<ResT> responseMarshaller;

webclient/grpc/src/main/java/io/helidon/webclient/grpc/GrpcClientConfigBlueprint.java

@@ -39,12 +39,11 @@ interface GrpcClientConfigBlueprint extends HttpClientConfig, Prototype.Factory<
     GrpcClientProtocolConfig protocolConfig();
 
     /**
-     * A {@link io.helidon.webclient.grpc.ClientUriSuppliers.ClientUriSupplier} that
-     * can dynamically provide zero or more {@link io.helidon.webclient.api.ClientUri}s
-     * to connect to.
+     * A {@link io.helidon.webclient.grpc.ClientUriSupplier} that can dynamically
+     * provide zero or more {@link io.helidon.webclient.api.ClientUri}s to connect.
      *
      * @return a supplier for zero or more client URIs
      */
-    Optional<ClientUriSuppliers.ClientUriSupplier> clientUriSupplier();
+    Optional<ClientUriSupplier> clientUriSupplier();
 }
 

webclient/tests/grpc/pom.xml

@@ -104,6 +104,11 @@
             <artifactId>helidon-webserver-testing-junit5-grpc</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.fault-tolerance</groupId>
+            <artifactId>helidon-fault-tolerance</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

webclient/tests/grpc/src/test/java/io/helidon/webclient/grpc/tests/GrpcClientUriTest.java

@@ -21,6 +21,7 @@
 
 import io.helidon.common.configurable.Resource;
 import io.helidon.common.tls.Tls;
+import io.helidon.faulttolerance.Retry;
 import io.helidon.webclient.api.ClientUri;
 import io.helidon.webclient.grpc.ClientUriSuppliers;
 import io.helidon.webclient.grpc.GrpcClient;
@@ -52,8 +53,11 @@ class GrpcClientUriTest extends GrpcBaseTest {
                 .build();
     }
 
+    /**
+     * Shows how each gRPC call advances the iterator in the {@code ClientUriSupplier}.
+     */
     @Test
-    void testClientUris() {
+    void testSupplier() {
         CountDownLatch latch = new CountDownLatch(2);
         ClientUri clientUri = ClientUri.create(URI.create("https://localhost:" + server.port()));
         GrpcClient grpcClient = GrpcClient.builder()
@@ -66,7 +70,26 @@ void testClientUris() {
         assertThat(res1.getText(), is("HELLO"));
         Strings.StringMessage res2 = service.upper(newStringMessage("hello"));
         assertThat(res2.getText(), is("HELLO"));
+        assertThat(latch.getCount(), is(0L));
+    }
+
+    /**
+     * Should fail to connect to first URI but succeed with second after retrying.
+     */
+    @Test
+    void testSupplierWithRetries() {
+        CountDownLatch latch = new CountDownLatch(2);
+        ClientUri badUri = ClientUri.create(URI.create("https://foo:8000"));
+        ClientUri goodUri = ClientUri.create(URI.create("https://localhost:" + server.port()));
+        GrpcClient grpcClient = GrpcClient.builder()
+                .tls(clientTls)
+                .clientUriSupplier(new ClientUriSupplierTest(latch, badUri, goodUri))
+                .build();
+        StringServiceGrpc.StringServiceBlockingStub service = StringServiceGrpc.newBlockingStub(grpcClient.channel());
 
+        Retry retry = Retry.builder().calls(2).build();
+        Strings.StringMessage res = retry.invoke(() -> service.upper(newStringMessage("hello")));
+        assertThat(res.getText(), is("HELLO"));
         assertThat(latch.getCount(), is(0L));
     }