spring cloud : spring cloud gateway - logging filter, load balancer

springcloud/apigateway-service/src/main/java/com/example/apigatewayservice/filter/LoggingFilter.java

@@ -0,0 +1,51 @@
+package com.example.apigatewayservice.filter;
+
+import lombok.Data;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.OrderedGatewayFilter;
+import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
+import org.springframework.core.Ordered;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.stereotype.Component;
+import reactor.core.publisher.Mono;
+
+@Component
+@Slf4j
+public class LoggingFilter extends AbstractGatewayFilterFactory<LoggingFilter.Config> {
+
+    public LoggingFilter() {
+        super(Config.class);
+    }
+
+    @Override
+    public GatewayFilter apply(Config config) {
+
+        GatewayFilter filter = new OrderedGatewayFilter((exchange, chain) -> {
+            ServerHttpRequest request = exchange.getRequest();
+            ServerHttpResponse response = exchange.getResponse();
+
+            log.info("Logging filter baseMessage : {}", config.getBaseMessage());
+
+            if (config.isPreLogger()) {
+                log.info("Logging PRE filter: request id -> {}", request.getId());
+            }
+
+            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
+                if (config.isPostLogger()) {
+                    log.info("Logging POST filter: response code -> {}", response.getStatusCode());
+                }
+            }));
+        }, Ordered.HIGHEST_PRECEDENCE);
+
+        return filter;
+    }
+
+    @Data
+    public static class Config {
+        private String baseMessage;
+        private boolean preLogger;
+        private boolean postLogger;
+    }
+}

springcloud/apigateway-service/src/main/resources/application.yml

@@ -3,8 +3,8 @@ server:
 
 eureka:
   client:
-    fetch-registry: false
-    register-with-eureka: false
+    fetch-registry: true
+    register-with-eureka: true
     service-url:
       defaultZone: http://localhost:8761/eureka
 
@@ -22,7 +22,7 @@ spring:
             postLogger: true
       routes:
         - id: first-service
-          uri: http://localhost:8081/
+          uri: lb://MY-FIRST-SERVICE
           predicates:
             - Path=/first-service/**
           filters:
@@ -30,10 +30,15 @@ spring:
 #            - AddResponseHeader=first-response, first-response-header2
             - CustomFilter
         - id: second-service
-          uri: http://localhost:8082/
+          uri: lb://MY-SECOND-SERVICE
           predicates:
             - Path=/second-service/**
           filters:
 #            - AddRequestHeader=second-request, second-request-header2
 #            - AddResponseHeader=second-response, second-response-header2
-            - CustomFilter
+            - name: CustomFilter
+            - name: LoggingFilter
+              args:
+                baseMessage: Hi, there.
+                preLogger: true
+                postLogger: true

springcloud/first-service/src/main/java/com/example/firstservice/FirstServiceController.java

@@ -1,16 +1,27 @@
 package com.example.firstservice;
 
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.env.Environment;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import javax.servlet.http.HttpServletRequest;
+
 @Slf4j
 @RestController
 @RequestMapping("/first-service")
 public class FirstServiceController {
 
+    Environment env;
+
+    @Autowired
+    public FirstServiceController(Environment env) {
+        this.env = env;
+    }
+
     @GetMapping("/welcome")
     public String welcome() {
         return "Welcome to the First Service.";
@@ -23,7 +34,9 @@ public class FirstServiceController {
     }
 
     @GetMapping("/check")
-    public String check() {
-        return "Hi, there. This is a message from first Service.";
+    public String check(HttpServletRequest request) {
+        log.info("Server port={}", request.getServerPort());
+        return String.format("Hi, there. This is a message from first Service on PORT %s",
+                env.getProperty("local.server.port"));
     }
 }

springcloud/first-service/src/main/resources/application.yml

@@ -1,10 +1,16 @@
 server:
-  port: 8081
+  port: 0
 
 spring:
   application:
     name: my-first-service
+
 eureka:
   client:
-    register-with-eureka: false
-    fetch-registry: false
+    fetch-registry: true
+    register-with-eureka: true
+    service-url:
+      defaultZone: http://localhost:8761/eureka
+
+  instance:
+    instance-id: ${spring.application.name}:${spring.application.instance-id:${random.value}}

springcloud/second-service/src/main/resources/application.yml

@@ -4,7 +4,10 @@ server:
 spring:
   application:
     name: my-second-service
+
 eureka:
   client:
-    register-with-eureka: false
-    fetch-registry: false
+    fetch-registry: true
+    register-with-eureka: true
+    service-url:
+      defaultZone: http://localhost:8761/eureka