[SCB-2164]InstanceCacheCheckTask only print necessary message to avoi…

service-registry/src/main/java/org/apache/servicecomb/serviceregistry/api/registry/MicroserviceInstance.java

@@ -69,6 +69,16 @@ public class MicroserviceInstance {
 
   private String timestamp;
 
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("instanceId=" + instanceId + ";");
+    sb.append("serviceId=" + serviceId + ";");
+    sb.append("status=" + status + ";");
+    sb.append("endpoints=" + endpoints.toString());
+    return sb.toString();
+  }
+
   public String getTimestamp() {
     return timestamp;
   }

service-registry/src/main/java/org/apache/servicecomb/serviceregistry/diagnosis/instance/InstanceCacheCheckTask.java

@@ -31,8 +31,6 @@
 import com.netflix.config.DynamicPropertyFactory;
 import com.netflix.config.DynamicStringProperty;
 
-import io.vertx.core.json.Json;
-
 public class InstanceCacheCheckTask implements ServiceRegistryTaskInitializer {
   private static final Logger LOGGER = LoggerFactory.getLogger(InstanceCacheCheckTask.class);
 
@@ -131,7 +129,7 @@ protected void runTask() {
       InstanceCacheSummary instanceCacheSummary = checker.check();
       eventBus.post(instanceCacheSummary);
 
-      LOGGER.info("check instance cache, result={}.", Json.encode(instanceCacheSummary));
+      LOGGER.info("check instance cache, result={}.", instanceCacheSummary.getStatus());
     } catch (Throwable e) {
       LOGGER.error("failed check instance cache..", e);
     }

service-registry/src/main/java/org/apache/servicecomb/serviceregistry/diagnosis/instance/InstanceCacheChecker.java

@@ -114,6 +114,11 @@ protected InstanceCacheResult check(MicroserviceVersions microserviceVersions) {
     String local = Json.encode(microserviceVersions.getPulledInstances());
     String remote = Json.encode(remoteInstances);
     if (local.equals(remote)) {
+      LOGGER.info("instance cache match. appId={}, microservice={}.\n"
+              + "current cache: {}\n",
+          microserviceVersions.getAppId(),
+          microserviceVersions.getMicroserviceName(),
+          remoteInstances.toString());
       instanceCacheResult.setStatus(Status.NORMAL);
       return instanceCacheResult;
     }
@@ -123,8 +128,8 @@ protected InstanceCacheResult check(MicroserviceVersions microserviceVersions) {
             + "remote cache: {}",
         microserviceVersions.getAppId(),
         microserviceVersions.getMicroserviceName(),
-        local,
-        remote);
+        microserviceVersions.getPulledInstances().toString(),
+        remoteInstances.toString());
     instanceCacheResult.setStatus(Status.ABNORMAL);
     instanceCacheResult.setDetail("instance cache not match");
 

service-registry/src/test/java/org/apache/servicecomb/serviceregistry/api/registry/TestMicroServiceInstance.java

@@ -83,6 +83,7 @@ public void testDefaultValues() {
     Assert.assertNull(oMicroserviceInstance.getHealthCheck());
     Assert.assertNull(oMicroserviceInstance.getStage());
     Assert.assertEquals(MicroserviceInstanceStatus.UP, oMicroserviceInstance.getStatus());
+    Assert.assertEquals("instanceId=null;serviceId=null;status=UP;endpoints=[]", oMicroserviceInstance.toString());
   }
 
   @SuppressWarnings("deprecation")
@@ -107,6 +108,8 @@ public void testInitializedValues() {
     Assert.assertNotEquals(oMicroserviceInstance.hashCode(), other.hashCode());
     Assert.assertEquals(oMicroserviceInstance, same);
     Assert.assertEquals(oMicroserviceInstance.hashCode(), same.hashCode());
+    Assert.assertEquals("instanceId=testInstanceID;serviceId=testServiceID;status=DOWN;endpoints=[testEndpoints]",
+        oMicroserviceInstance.toString());
   }
 
   @SuppressWarnings("deprecation")