Support seata feign loadbalancer

spring-cloud-alibaba-seata/pom.xml

@@ -38,6 +38,12 @@
             <optional>true</optional>
         </dependency>
 
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-loadbalancer</artifactId>
+            <optional>true</optional>
+        </dependency>
+
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>

spring-cloud-alibaba-seata/src/main/java/com/alibaba/cloud/seata/feign/SeataFeignBlockingLoadBalancerClient.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2013-2018 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 com.alibaba.cloud.seata.feign;
+
+import java.io.IOException;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import feign.Client;
+import feign.Request;
+import feign.Response;
+import io.seata.core.context.RootContext;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
+import org.springframework.http.HttpStatus;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * @author yuhuangbin
+ */
+public class SeataFeignBlockingLoadBalancerClient implements Client {
+
+	private static final Log LOG = LogFactory
+			.getLog(SeataFeignBlockingLoadBalancerClient.class);
+
+	private final Client delegate;
+
+	private final BlockingLoadBalancerClient loadBalancerClient;
+
+	SeataFeignBlockingLoadBalancerClient(Client delegate,
+			BlockingLoadBalancerClient loadBalancerClient) {
+		this.delegate = delegate;
+		this.loadBalancerClient = loadBalancerClient;
+	}
+
+	@Override
+	public Response execute(Request request, Request.Options options) throws IOException {
+		final URI originalUri = URI.create(request.url());
+		String serviceId = originalUri.getHost();
+		Assert.state(serviceId != null,
+				"Request URI does not contain a valid hostname: " + originalUri);
+		ServiceInstance instance = loadBalancerClient.choose(serviceId);
+		if (instance == null) {
+			String message = "Load balancer does not contain an instance for the service "
+					+ serviceId;
+			if (LOG.isWarnEnabled()) {
+				LOG.warn(message);
+			}
+			return Response.builder().request(request)
+					.status(HttpStatus.SERVICE_UNAVAILABLE.value())
+					.body(message, StandardCharsets.UTF_8).build();
+		}
+		String reconstructedUrl = loadBalancerClient.reconstructURI(instance, originalUri)
+				.toString();
+		Request newRequest = Request.create(request.httpMethod(), reconstructedUrl,
+				enrichRequstHeader(request.headers()), request.requestBody());
+
+		return delegate.execute(newRequest, options);
+	}
+
+	private Map<String, Collection<String>> enrichRequstHeader(
+			Map<String, Collection<String>> headers) {
+		String xid = RootContext.getXID();
+		if (!StringUtils.isEmpty(xid)) {
+			Map<String, Collection<String>> newHeaders = new HashMap<>();
+			newHeaders.putAll(headers);
+			newHeaders.put(RootContext.KEY_XID, Arrays.asList(xid));
+			return newHeaders;
+		}
+		return headers;
+	}
+
+}

spring-cloud-alibaba-seata/src/main/java/com/alibaba/cloud/seata/feign/SeataFeignObjectWrapper.java

@@ -16,9 +16,14 @@
 
 package com.alibaba.cloud.seata.feign;
 
+import java.lang.reflect.Field;
+
 import feign.Client;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.BeanFactory;
+import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
 import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
 import org.springframework.cloud.openfeign.ribbon.CachingSpringLoadBalancerFactory;
 import org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient;
@@ -28,12 +33,16 @@ import org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient;
  */
 public class SeataFeignObjectWrapper {
 
+	private static final Log LOG = LogFactory.getLog(SeataFeignObjectWrapper.class);
+
 	private final BeanFactory beanFactory;
 
 	private CachingSpringLoadBalancerFactory cachingSpringLoadBalancerFactory;
 
 	private SpringClientFactory springClientFactory;
 
+	private BlockingLoadBalancerClient loadBalancerClient;
+
 	SeataFeignObjectWrapper(BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 	}
@@ -45,11 +54,41 @@ public class SeataFeignObjectWrapper {
 				return new SeataLoadBalancerFeignClient(client.getDelegate(), factory(),
 						clientFactory(), this.beanFactory);
 			}
+			if (bean.getClass().getName().equals(
+					"org.springframework.cloud.openfeign.loadbalancer.FeignBlockingLoadBalancerClient")) {
+				return new SeataFeignBlockingLoadBalancerClient(getClient(bean),
+						loadBalancerClient());
+			}
 			return new SeataFeignClient(this.beanFactory, (Client) bean);
 		}
 		return bean;
 	}
 
+	private Client getClient(Object bean) {
+		Field client = null;
+		boolean oldAccessible = false;
+		try {
+			client = bean.getClass().getDeclaredField("delegate");
+			oldAccessible = client.isAccessible();
+			client.setAccessible(true);
+			return (Client) client.get(bean);
+		}
+		catch (Exception e) {
+			LOG.error("get delegate client error", e);
+		}
+		finally {
+			client.setAccessible(oldAccessible);
+		}
+		return null;
+	}
+
+	private BlockingLoadBalancerClient loadBalancerClient() {
+		if (this.loadBalancerClient != null) {
+			return this.loadBalancerClient;
+		}
+		return beanFactory.getBean(BlockingLoadBalancerClient.class);
+	}
+
 	CachingSpringLoadBalancerFactory factory() {
 		if (this.cachingSpringLoadBalancerFactory == null) {
 			this.cachingSpringLoadBalancerFactory = this.beanFactory