refactor the hard code with Eureka to support optional Eureka and Nacos.

src/main/java/we/proxy/AbstractDiscoveryClientUriSelector.java

@@ -0,0 +1,17 @@
+package we.proxy;
+
+import we.util.Constants;
+import we.util.ThreadContext;
+
+/**
+ * Abstract implementation of {@code DiscoveryClientUriSelector}
+ *
+ * @author zhongjie
+ */
+abstract public class AbstractDiscoveryClientUriSelector implements DiscoveryClientUriSelector {
+
+    protected String buildUri(String ipAddr, int port, String path) {
+        StringBuilder b = ThreadContext.getStringBuilder();
+        return b.append(Constants.Symbol.HTTP_PROTOCOL_PREFIX).append(ipAddr).append(Constants.Symbol.COLON).append(port).append(path).toString();
+    }
+}

src/main/java/we/proxy/DisableDiscoveryUriSelector.java

@@ -0,0 +1,19 @@
+package we.proxy;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
+import org.springframework.stereotype.Service;
+
+/**
+ * The disable implementation of {@code DiscoveryClientUriSelector}, used when Nacos and Eureka discovery are not enabled.
+ *
+ * @author zhongjie
+ */
+
+@ConditionalOnExpression("${nacos.discovery.enabled} == false and ${eureka.client.enabled} == false")
+@Service
+public class DisableDiscoveryUriSelector implements DiscoveryClientUriSelector {
+    @Override
+    public String getNextUri(String service, String relativeUri) {
+        throw new RuntimeException("No " + service + " because discovery disabled", null, false, false) {};
+    }
+}

src/main/java/we/proxy/DiscoveryClientUriSelector.java

@@ -0,0 +1,16 @@
+package we.proxy;
+
+/**
+ * A {@code DiscoveryClientUriSelector} is used to select the uri for the next request
+ *
+ * @author zhongjie
+ */
+public interface DiscoveryClientUriSelector {
+    /**
+     * find a instance of service by discovery and return the uri that http://{instance-ip-addr}:{instance-port}{relativeUri}
+     * @param service service name
+     * @param relativeUri relative uri
+     * @return the uri for the next request
+     */
+    String getNextUri(String service, String relativeUri);
+}

src/main/java/we/proxy/EurekaUriSelector.java

@@ -0,0 +1,55 @@
+package we.proxy;
+
+import com.netflix.appinfo.InstanceInfo;
+import com.netflix.discovery.EurekaClient;
+import com.netflix.discovery.shared.Applications;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.stereotype.Service;
+
+import javax.annotation.Resource;
+import java.util.List;
+
+/**
+ * The Eureka implementation of {@code DiscoveryClientUriSelector}
+ *
+ * @author zhongjie
+ */
+@ConditionalOnProperty(value = "eureka.client.enabled", matchIfMissing = true)
+@Service
+public class EurekaUriSelector extends AbstractDiscoveryClientUriSelector {
+
+    @Resource
+    private EurekaClient eurekaClient;
+
+    @Override
+    public String getNextUri(String service, String relativeUri) {
+        InstanceInfo inst = roundRobinChoose1instFrom(service);
+        return buildUri(inst.getIPAddr(), inst.getPort(), relativeUri);
+    }
+
+
+    // private static List<InstanceInfo> aggrMemberInsts = new ArrayList<>();
+    // static {
+    //     InstanceInfo i0 = InstanceInfo.Builder.newBuilder().setAppName("TRIP-MINI").setIPAddr("xxx.25.63.192").setPort(7094).build();
+    //     aggrMemberInsts.add(i0);
+    // }
+    // private static AtomicLong counter = new AtomicLong(0);
+    // private static final String aggrMember = "trip-mini";
+
+
+    private InstanceInfo roundRobinChoose1instFrom(String service) {
+
+        // if (aggrMember.equals(service)) {
+        //     int idx = (int) (counter.incrementAndGet() % aggrMemberInsts.size());
+        //     return aggrMemberInsts.get(idx);
+        // }
+
+        List<InstanceInfo> insts = eurekaClient.getInstancesByVipAddress(service, false);
+        if (insts == null || insts.isEmpty()) {
+            throw new RuntimeException("eureka no " + service, null, false, false) {};
+        }
+        Applications apps = eurekaClient.getApplications();
+        int index = (int) (apps.getNextIndex(service.toUpperCase(), false).incrementAndGet() % insts.size());
+        return insts.get(index);
+    }
+}

src/main/java/we/proxy/FizzWebClient.java

@@ -17,10 +17,7 @@
 
 package we.proxy;
 
-import com.netflix.appinfo.InstanceInfo;
-import com.netflix.discovery.EurekaClient;
-import com.netflix.discovery.shared.Applications;
-
+import com.alibaba.nacos.api.config.annotation.NacosValue;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
@@ -43,10 +40,7 @@ import we.util.WebUtils;
 
 import javax.annotation.PostConstruct;
 import javax.annotation.Resource;
-import java.util.ArrayList;
-import java.util.List;
 import java.util.concurrent.ThreadLocalRandom;
-import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * @author hongqiaowei
@@ -62,7 +56,7 @@ public class FizzWebClient {
     private static final String localhost    = "localhost";
 
     @Resource
-    private EurekaClient eurekaClient;
+    private DiscoveryClientUriSelector discoveryClientUriSelector;
 
     @Resource(name = ProxyWebClientConfig.proxyWebClient)
     private WebClient proxyWebClient;
@@ -70,6 +64,7 @@ public class FizzWebClient {
     @Resource(name = AggrWebClientConfig.aggrWebClient)
     private WebClient aggrWebClient;
 
+    @NacosValue(value = "${fizz-web-client.timeout:-1}")
     @Value("${fizz-web-client.timeout:-1}")
     private long timeout = -1;
 
@@ -140,8 +135,7 @@ public class FizzWebClient {
         // what about multiple nginx instance
 
         // current
-        InstanceInfo inst = roundRobinChoose1instFrom(service);
-        String uri = buildUri(inst, relativeUri);
+        String uri = discoveryClientUriSelector.getNextUri(service, relativeUri);
         return send2uri(originReqIdOrBizId, method, uri, headers, body, cbc);
     }
 
@@ -225,37 +219,8 @@ public class FizzWebClient {
         // TODO 请求完成后，做metric, 以反哺后续的请求转发
     }
 
-    private String buildUri(InstanceInfo inst, String path) {
-        StringBuilder b = ThreadContext.getStringBuilder();
-        return b.append(Constants.Symbol.HTTP_PROTOCOL_PREFIX).append(inst.getIPAddr()).append(Constants.Symbol.COLON).append(inst.getPort()).append(path).toString();
-    }
 
 
-    // private static List<InstanceInfo> aggrMemberInsts = new ArrayList<>();
-    // static {
-    //     InstanceInfo i0 = InstanceInfo.Builder.newBuilder().setAppName("TRIP-MINI").setIPAddr("xxx.25.63.192").setPort(7094).build();
-    //     aggrMemberInsts.add(i0);
-    // }
-    // private static AtomicLong counter = new AtomicLong(0);
-    // private static final String aggrMember = "trip-mini";
-
-
-    private InstanceInfo roundRobinChoose1instFrom(String service) {
-
-        // if (aggrMember.equals(service)) {
-        //     int idx = (int) (counter.incrementAndGet() % aggrMemberInsts.size());
-        //     return aggrMemberInsts.get(idx);
-        // }
-
-        List<InstanceInfo> insts = eurekaClient.getInstancesByVipAddress(service, false);
-        if (insts == null || insts.isEmpty()) {
-            throw new RuntimeException("eureka no " + service, null, false, false) {};
-        }
-        Applications apps = eurekaClient.getApplications();
-        int index = (int) (apps.getNextIndex(service.toUpperCase(), false).incrementAndGet() % insts.size());
-        return insts.get(index);
-    }
-
     private String extractServiceOrAddress(String uriOrSvc) {
         return uriOrSvc.substring(7, uriOrSvc.indexOf(Constants.Symbol.FORWARD_SLASH, 10));
     }

src/main/java/we/proxy/NacosUriSelector.java

@@ -0,0 +1,46 @@
+package we.proxy;
+
+import com.alibaba.nacos.api.exception.NacosException;
+import com.alibaba.nacos.api.naming.NamingService;
+import com.alibaba.nacos.api.naming.pojo.Instance;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.stereotype.Service;
+
+import javax.annotation.Resource;
+
+/**
+ * The Nacos implementation of {@code DiscoveryClientUriSelector}
+ *
+ * @author zhongjie
+ */
+@ConditionalOnProperty(value = "nacos.discovery.enabled")
+@Service
+public class NacosUriSelector extends AbstractDiscoveryClientUriSelector {
+    private static final Logger log = LoggerFactory.getLogger(NacosUriSelector.class);
+
+    @Resource
+    private NamingService naming;
+
+    @Override
+    public String getNextUri(String service, String relativeUri) {
+        Instance instance = this.selectOneHealthyInstance(service);
+        return super.buildUri(instance.getIp(), instance.getPort(), relativeUri);
+    }
+
+    private Instance selectOneHealthyInstance(String service) {
+        Instance instance = null;
+        try {
+            instance = naming.selectOneHealthyInstance(service);
+        } catch (NacosException e) {
+            log.warn("Nacos selectOneHealthyInstance({}) exception", service, e);
+        }
+
+        if (instance == null) {
+            throw new RuntimeException("Nacos no " + service, null, false, false) {};
+        }
+
+        return instance;
+    }
+}