Support java 11 http2 client gh-689 (#869)

docs/src/main/asciidoc/spring-cloud-openfeign.adoc

@@ -140,10 +140,10 @@ If none of them is on the classpath, the default feign client is used.
 
 NOTE: `spring-cloud-starter-openfeign` supports `spring-cloud-starter-loadbalancer`. However, as is an optional dependency, you need to make sure it has been added to your project if you want to use it.
 
-The OkHttpClient and Apache HttpClient 5 Feign clients can be used by setting `spring.cloud.openfeign.okhttp.enabled` or `spring.cloud.openfeign.httpclient.hc5.enabled` to `true`, respectively, and having them on the classpath.
+The OkHttpClient, Apache HttpClient 5 and Http2Client Feign clients can be used by setting `spring.cloud.openfeign.okhttp.enabled` or `spring.cloud.openfeign.httpclient.hc5.enabled` or `spring.cloud.openfeign.http2client.enabled` to `true`, respectively, and having them on the classpath.
 You can customize the HTTP client used by providing a bean of either `org.apache.hc.client5.http.impl.classic.CloseableHttpClient` when using Apache HC5.
 
-You can further customise http clients by setting values in the `spring.cloud.openfeign.httpclient.xxx` properties. The ones prefixed just with `httpclient` will work for all the clients, the ones prefixed with `httpclient.hc5` to Apache HttpClient 5 and the ones prefixed with `httpclient.okhttp` to OkHttpClient. You can find a full list of properties you can customise in the appendix.
+You can further customise http clients by setting values in the `spring.cloud.openfeign.httpclient.xxx` properties. The ones prefixed just with `httpclient` will work for all the clients, the ones prefixed with `httpclient.hc5` to Apache HttpClient 5, the ones prefixed with `httpclient.okhttp` to OkHttpClient and the ones prefixed with `httpclient.http2` to Http2Client. You can find a full list of properties you can customise in the appendix.
 
 TIP: Starting with Spring Cloud OpenFeign 4, the Feign Apache HttpClient 4 is no longer supported. We suggest using Apache HttpClient 5 instead.
 

spring-cloud-openfeign-core/pom.xml

@@ -133,6 +133,11 @@
 			<artifactId>feign-okhttp</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>io.github.openfeign</groupId>
+			<artifactId>feign-java11</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>com.squareup.okhttp3</groupId>
 			<artifactId>okhttp</artifactId>

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/FeignAutoConfiguration.java

@@ -17,6 +17,7 @@
 package org.springframework.cloud.openfeign;
 
 import java.lang.reflect.Method;
+import java.net.http.HttpClient;
 import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.security.cert.X509Certificate;
@@ -39,6 +40,7 @@
 import feign.Feign;
 import feign.Target;
 import feign.hc5.ApacheHttp5Client;
+import feign.http2client.Http2Client;
 import feign.okhttp.OkHttpClient;
 import jakarta.annotation.PreDestroy;
 import okhttp3.ConnectionPool;
@@ -383,6 +385,25 @@ public OAuth2AccessTokenInterceptor defaultOAuth2AccessTokenInterceptor(
 
 	}
 
+	// the following configuration is for alternate feign clients if
+	// SC loadbalancer is not on the class path.
+	// see corresponding configurations in FeignLoadBalancerAutoConfiguration
+	// for load-balanced clients.
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass({ Http2Client.class, HttpClient.class })
+	@ConditionalOnMissingBean(HttpClient.class)
+	@ConditionalOnProperty("spring.cloud.openfeign.http2client.enabled")
+	@Import(org.springframework.cloud.openfeign.clientconfig.Http2ClientFeignConfiguration.class)
+	protected static class Http2ClientFeignConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(Client.class)
+		public Client feignClient(HttpClient httpClient) {
+			return new Http2Client(httpClient);
+		}
+
+	}
+
 }
 
 class FeignHints implements RuntimeHintsRegistrar {

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/clientconfig/Http2ClientFeignConfiguration.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2013-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.cloud.openfeign.clientconfig;
+
+import java.net.http.HttpClient;
+import java.time.Duration;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.cloud.openfeign.support.FeignHttpClientProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Default configuration for {@link HttpClient}.
+ *
+ * @author changjin wei(魏昌进)
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnMissingBean(HttpClient.class)
+public class Http2ClientFeignConfiguration {
+
+	@Bean
+	public HttpClient httpClient(FeignHttpClientProperties httpClientProperties) {
+		return HttpClient.newBuilder()
+				.followRedirects(httpClientProperties.isFollowRedirects() ? HttpClient.Redirect.ALWAYS
+						: HttpClient.Redirect.NEVER)
+				.version(HttpClient.Version.valueOf(httpClientProperties.getHttp2().getVersion()))
+				.connectTimeout(Duration.ofMillis(httpClientProperties.getConnectionTimeout())).build();
+	}
+
+}

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/loadbalancer/FeignLoadBalancerAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2022 the original author or authors.
+ * Copyright 2013-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,7 +54,7 @@
 // see
 // https://github.com/spring-cloud/spring-cloud-netflix/issues/2086#issuecomment-316281653
 @Import({ OkHttpFeignLoadBalancerConfiguration.class, HttpClient5FeignLoadBalancerConfiguration.class,
-		DefaultFeignLoadBalancerConfiguration.class })
+		Http2ClientFeignLoadBalancerConfiguration.class, DefaultFeignLoadBalancerConfiguration.class })
 public class FeignLoadBalancerAutoConfiguration {
 
 	@Bean

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/loadbalancer/Http2ClientFeignLoadBalancerConfiguration.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2013-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.cloud.openfeign.loadbalancer;
+
+import java.net.http.HttpClient;
+import java.util.List;
+
+import feign.Client;
+import feign.http2client.Http2Client;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryFactory;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerClientsProperties;
+import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Conditional;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Configuration instantiating a {@link LoadBalancerClient}-based {@link Client} object
+ * that uses {@link Http2Client} under the hood.
+ *
+ * @author changjin wei(魏昌进)
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass({ Http2Client.class, HttpClient.class })
+@ConditionalOnBean({ LoadBalancerClient.class, LoadBalancerClientFactory.class })
+@ConditionalOnProperty("spring.cloud.openfeign.http2client.enabled")
+@EnableConfigurationProperties(LoadBalancerClientsProperties.class)
+class Http2ClientFeignLoadBalancerConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean
+	@Conditional(OnRetryNotEnabledCondition.class)
+	public Client feignClient(LoadBalancerClient loadBalancerClient, HttpClient httpClient,
+			LoadBalancerClientFactory loadBalancerClientFactory,
+			List<LoadBalancerFeignRequestTransformer> transformers) {
+		Client delegate = new Http2Client(httpClient);
+		return new FeignBlockingLoadBalancerClient(delegate, loadBalancerClient, loadBalancerClientFactory,
+				transformers);
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	@ConditionalOnClass(name = "org.springframework.retry.support.RetryTemplate")
+	@ConditionalOnBean(LoadBalancedRetryFactory.class)
+	@ConditionalOnProperty(value = "spring.cloud.loadbalancer.retry.enabled", havingValue = "true",
+			matchIfMissing = true)
+	public Client feignRetryClient(LoadBalancerClient loadBalancerClient, HttpClient httpClient,
+			LoadBalancedRetryFactory loadBalancedRetryFactory, LoadBalancerClientFactory loadBalancerClientFactory,
+			List<LoadBalancerFeignRequestTransformer> transformers) {
+		Client delegate = new Http2Client(httpClient);
+		return new RetryableFeignBlockingLoadBalancerClient(delegate, loadBalancerClient, loadBalancedRetryFactory,
+				loadBalancerClientFactory, transformers);
+	}
+
+}

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/FeignHttpClientProperties.java

@@ -16,10 +16,12 @@
 
 package org.springframework.cloud.openfeign.support;
 
+import java.net.http.HttpClient;
 import java.time.Duration;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+import feign.http2client.Http2Client;
 import feign.okhttp.OkHttpClient;
 import okhttp3.Protocol;
 
@@ -100,6 +102,11 @@ public class FeignHttpClientProperties {
 	 */
 	private OkHttp okHttp = new OkHttp();
 
+	/**
+	 * Additional {@link Http2Client}-specific properties.
+	 */
+	private Http2Properties http2 = new Http2Properties();
+
 	public int getConnectionTimerRepeat() {
 		return connectionTimerRepeat;
 	}
@@ -180,6 +187,14 @@ public void setOkHttp(OkHttp okHttp) {
 		this.okHttp = okHttp;
 	}
 
+	public Http2Properties getHttp2() {
+		return http2;
+	}
+
+	public void setHttp2(Http2Properties http2) {
+		this.http2 = http2;
+	}
+
 	public static class Hc5Properties {
 
 		/**
@@ -362,4 +377,25 @@ public void setProtocols(List<String> protocols) {
 
 	}
 
+	/**
+	 * {@link Http2Client}-specific properties.
+	 */
+	public static class Http2Properties {
+
+		/**
+		 * Configure the protocols used by this client to communicate with remote servers.
+		 * Uses {@link String} value of {@link HttpClient.Version}.
+		 */
+		private String version = "HTTP_2";
+
+		public String getVersion() {
+			return version;
+		}
+
+		public void setVersion(String version) {
+			this.version = version;
+		}
+
+	}
+
 }

spring-cloud-openfeign-core/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -44,6 +44,12 @@
 			"description": "Enables the use of the OK HTTP Client by Feign.",
 			"defaultValue": "false"
 		},
+		{
+			"name": "spring.cloud.openfeign.http2client.enabled",
+			"type": "java.lang.Boolean",
+			"description": "Enables the use of the Java11 HTTP 2 Client by Feign.",
+			"defaultValue": "false"
+		},
 		{
 			"name": "spring.cloud.openfeign.compression.response.enabled",
 			"type": "java.lang.Boolean",

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/FeignHttp2ClientConfigurationTests.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2013-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.cloud.openfeign;
+
+import java.net.http.HttpClient;
+import java.time.Duration;
+import java.util.Optional;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.context.ConfigurableApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author changjin wei(魏昌进)
+ */
+class FeignHttp2ClientConfigurationTests {
+
+	private ConfigurableApplicationContext context;
+
+	@BeforeEach
+	void setUp() {
+		context = new SpringApplicationBuilder()
+				.properties("debug=true", "spring.cloud.openfeign.http2client.enabled=true",
+						"spring.cloud.openfeign.httpclient.http2.version=HTTP_1_1",
+						"spring.cloud.openfeign.httpclient.connectionTimeout=15")
+				.web(WebApplicationType.NONE).sources(FeignAutoConfiguration.class).run();
+	}
+
+	@AfterEach
+	void tearDown() {
+		if (context != null) {
+			context.close();
+		}
+	}
+
+	@Test
+	void shouldConfigureConnectTimeout() {
+		HttpClient httpClient = context.getBean(HttpClient.class);
+
+		assertThat(httpClient.connectTimeout()).isEqualTo(Optional.ofNullable(Duration.ofMillis(15)));
+	}
+
+	@Test
+	void shouldResolveVersionFromProperties() {
+		HttpClient httpClient = context.getBean(HttpClient.class);
+
+		assertThat(httpClient.version()).isEqualTo(HttpClient.Version.HTTP_1_1);
+	}
+
+}