bugfix: fix prometheus fail to return seata metrics data when using Nacos (apache#6786)

Author: slievrly

changes/en-us/2.x.md

@@ -30,6 +30,7 @@ Add changes here for all PR submitted to the 2.x branch.
 - [[#6778](https://github.com/apache/incubator-seata/pull/6778)] fix namingserver node term
 - [[#6765](https://github.com/apache/incubator-seata/pull/6765)] fix MySQL driver loading by replacing custom classloader with system classloader for better compatibility and simplified process
 - [[#6781](https://github.com/apache/incubator-seata/pull/6781)] the issue where the TC occasionally fails to go offline from the NamingServer
+- [[#6785](https://github.com/apache/incubator-seata/pull/6785)] fix prometheus fail to return seata metrics data when using Nacos
 - [[#6797](https://github.com/apache/incubator-seata/pull/6797)] fall back to any of available cluster address when query cluster address is empty
 - [[#6800](https://github.com/apache/incubator-seata/pull/6800)] make exception message generic for all database drivers
 - [[#6759](https://github.com/apache/incubator-seata/pull/6759)] fix the error of active refresh failure of cross-database table metadata

changes/zh-cn/2.x.md

@@ -31,6 +31,7 @@
 - [[#6778](https://github.com/apache/incubator-seata/pull/6778)] 修复namingserver的节点term为0问题
 - [[#6765](https://github.com/apache/incubator-seata/pull/6765)] 改进MySQL驱动加载机制，将自定义类加载器替换为系统类加载器，更兼容简化流程
 - [[#6781](https://github.com/apache/incubator-seata/pull/6781)] 修复tc下线时,由于定时任务没有先关闭,导致下线后还会被注册上,需要靠namingserver的健康检查来下线的bug
+- [[#6785](https://github.com/apache/incubator-seata/pull/6785)] 修复 prometheus 在与 Nacos 集成时无法返回 seata metrics 数据的问题
 - [[#6797](https://github.com/apache/incubator-seata/pull/6797)] 当查询的集群地址为空时，获取可用的任意集群地址
 - [[#6800](https://github.com/apache/incubator-seata/pull/6800)] 使异常消息对所有数据库驱动程序通用
 - [[#6812](https://github.com/apache/incubator-seata/pull/6812)] 修复切换事务分组和节点下线时namingserver没有实时感知和推送的bug

common/src/main/java/org/apache/seata/common/DefaultValues.java

@@ -259,7 +259,7 @@ public interface DefaultValues {
     /**
      * the const DEFAULT_METRICS_ENABLED
      */
-    boolean DEFAULT_METRICS_ENABLED = false;
+    boolean DEFAULT_METRICS_ENABLED = true;
 
     /**
      * the const DEFAULT_METRICS_REGISTRY_TYPE

metrics/seata-metrics-exporter-prometheus/src/main/java/org/apache/seata/metrics/exporter/prometheus/PrometheusExporter.java

@@ -17,12 +17,14 @@
 package org.apache.seata.metrics.exporter.prometheus;
 
 import java.io.IOException;
+import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map.Entry;
 
 import io.prometheus.client.Collector;
 import io.prometheus.client.Collector.MetricFamilySamples.Sample;
+import io.prometheus.client.CollectorRegistry;
 import io.prometheus.client.exporter.HTTPServer;
 import org.apache.seata.common.loader.LoadLevel;
 import org.apache.seata.config.ConfigurationFactory;
@@ -48,8 +50,9 @@ public class PrometheusExporter extends Collector implements Collector.Describab
     public PrometheusExporter() throws IOException {
         int port = ConfigurationFactory.getInstance().getInt(
             ConfigurationKeys.METRICS_PREFIX + METRICS_EXPORTER_PROMETHEUS_PORT, DEFAULT_PROMETHEUS_PORT);
-        this.server = new HTTPServer(port, true);
-        this.register();
+        CollectorRegistry collectorRegistry = new CollectorRegistry(true);
+        this.register(collectorRegistry);
+        this.server = new HTTPServer(new InetSocketAddress(port),collectorRegistry, true);
     }
 
     @Override

script/config-center/config.txt

@@ -164,7 +164,7 @@ server.raft.sync=true
 
 
 #Metrics configuration, only for the server
-metrics.enabled=false
+metrics.enabled=true
 metrics.registryType=compact
 metrics.exporterList=prometheus
 metrics.exporterPrometheusPort=9898