Dubbo 3.2 监控体系核心源码解读

傷城~ 2024-03-17 17:13 12阅读 0赞

### 一、核心类以及含义 ###

<table> 
 <thead> 
  <tr> 
   <th>对象</th> 
   <th>作用</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>MetricsConfig</td> 
   <td>监控指标的配置类，支持具体指标类型的开关，例如可将注册中心的指标关闭</td> 
  </tr> 
  <tr> 
   <td>MetricSample</td> 
   <td>指标收集样本，定义指标名称、tag、描述、类别等,直接与micrometer交互打点</td> 
  </tr> 
  <tr> 
   <td>MetricsLevel</td> 
   <td>监控指标级别：app、service、method、config</td> 
  </tr> 
  <tr> 
   <td>MetricsCat</td> 
   <td>一个组合对象，参数有：指标、对应的更新指标值的函数</td> 
  </tr> 
  <tr> 
   <td>MetricsCategory</td> 
   <td>指标类别（注册、元数据、请求、线程池等）</td> 
  </tr> 
  <tr> 
   <td>MetricsExport</td> 
   <td>export方法获取所有的 MetricSample 数据</td> 
  </tr> 
  <tr> 
   <td>AbstractMetricsExport</td> 
   <td>初始化的MetricsKey</td> 
  </tr> 
  <tr> 
   <td>CombMetricsCollector</td> 
   <td>指标收集器的抽象类，核心方法有记录 rt、自增指标、获取所有的指标样本 MetricSample 以编译通过 micromiter 打点</td> 
  </tr> 
  <tr> 
   <td>DefaultMetricsCollector</td> 
   <td>默认的指标收集器，负责收集请求类型的指标、线程池指标</td> 
  </tr> 
 </tbody> 
</table>

### 二、注册指标的收集 ###

#### 1. 定义指标类型 ####

构造函数定义收集的指标类型：应用与服务级别的注册、订阅、收到推送后的 notify 的成功、失败数量

public RegistryMetricsCollector(ApplicationModel applicationModel) {
        
            super(new BaseStatComposite(applicationModel) {
        
                @Override
                protected void init(ApplicationStatComposite applicationStatComposite) {
        
                    super.init(applicationStatComposite);
                    applicationStatComposite.init(RegistryMetricsConstants.APP_LEVEL_KEYS);
                }
        }
             @Override
                protected void init(ServiceStatComposite serviceStatComposite) {
        
                    super.init(serviceStatComposite);
                    serviceStatComposite.initWrapper(RegistryMetricsConstants.SERVICE_LEVEL_KEYS);
                }
    
                @Override
                protected void init(RtStatComposite rtStatComposite) {
        
                    super.init(rtStatComposite);
                    rtStatComposite.init(OP_TYPE_REGISTER, OP_TYPE_SUBSCRIBE, OP_TYPE_NOTIFY, OP_TYPE_REGISTER_SERVICE, OP_TYPE_SUBSCRIBE_SERVICE);
                }
                //...省略无关代码

#### 2. 订阅指标变更 ####

初始化注册指标收集器的时候创建指标定义对象 RegistrySubDispatcher

public RegistryMetricsCollector(ApplicationModel applicationModel) {
        
    //...省略无关代码
            super.setEventMulticaster(new RegistrySubDispatcher(this));
            this.applicationModel = applicationModel;
        }

在 RegistrySubDispatcher 中遍历了指标类型，为每个指标类型添加监听器，当收到指标变更事件时自动更新指标

public RegistrySubDispatcher(RegistryMetricsCollector collector) {
        
    
            CategorySet.ALL.forEach(categorySet ->
            {
        
                super.addListener(categorySet.getPost().getEventFunc().apply(collector));
                if (categorySet.getFinish() != null) {
        
                    super.addListener(categorySet.getFinish().getEventFunc().apply(collector));
                }
                if (categorySet.getError() != null) {
        
                    super.addListener(categorySet.getError().getEventFunc().apply(collector));
                }
            });
        }

#### 3. 收集指标集合 ####

从应用、rt、服务、方法四个维度收集指标集合

@Override
        public List<MetricSample> collect() {
        
            List<MetricSample> list = new ArrayList<>();
            if (!isCollectEnabled()) {
        
                return list;
            }
            list.addAll(super.export(MetricsCategory.REGISTRY));
            return list;
        }

#### 4. 注册行为监控打点 ####

启动时自动注册，使用静态类 MetricsEventBus 的 post 方法进行打点，该 post 方法会触发 MetricsDispatcher 发布注册监控事件，也会执行 MetricsDispatcher 对应的 listener ，最终执行 RegistryMetricsCollector 对应的 onEvent 方法，而该方法又会触发 MetricsEventMulticaster 对象的 publishEvent 方法，从而执行注册指标的对应的监听器最终将数据收集到各个 StatComposite 中

private void registerServiceInstance() {
        
            try {
        
                registered = true;
                MetricsEventBus.post(RegistryEvent.toRegisterEvent(applicationModel),
                    () -> {
        
                        ServiceInstanceMetadataUtils.registerMetadataAndInstance(applicationModel);
                        return null;
                    }
                );
            } catch (Exception e) {
        
                logger.error(CONFIG_REGISTER_INSTANCE_ERROR, "configuration server disconnected", "", "Register instance error.", e);
            }
    //省略无关代码

#### 5. 指标收集到 micrometer ####

定时执行收集任务

private void scheduleMetricsCollectorSyncJob() {
        
            NamedThreadFactory threadFactory = new NamedThreadFactory("metrics-collector-sync-job", true);
            collectorSyncJobExecutor = Executors.newScheduledThreadPool(1, threadFactory);
            collectorSyncJobExecutor.scheduleWithFixedDelay(this::refreshData, DEFAULT_SCHEDULE_INITIAL_DELAY, DEFAULT_SCHEDULE_PERIOD, TimeUnit.SECONDS);
        }

遍历每个指标收集器将收集到的指标样本通过 micrometer 记录起来

public void refreshData() {
        
            collectors.forEach(collector -> {
        
                List<MetricSample> samples = collector.collect();
                for (MetricSample sample : samples) {
        
                    try {
        
                        switch (sample.getType()) {
        
                            case GAUGE:
                                GaugeMetricSample gaugeSample = (GaugeMetricSample) sample;
                                List<Tag> tags = getTags(gaugeSample);
    
                                Gauge.builder(gaugeSample.getName(), gaugeSample.getValue(), gaugeSample.getApply())
                                    .description(gaugeSample.getDescription()).tags(tags).register(compositeRegistry);
                                break;
                            case COUNTER:
                                CounterMetricSample counterMetricSample = (CounterMetricSample) sample;
                                FunctionCounter.builder(counterMetricSample.getName(),  counterMetricSample.getValue(),
                                        Number::doubleValue).description(counterMetricSample.getDescription())
                                    .tags(getTags(counterMetricSample))
                                    .register(compositeRegistry);
                            case TIMER:
                            case LONG_TASK_TIMER:
                            case DISTRIBUTION_SUMMARY:
                                // TODO
                                break;
                            default:
                                break;
                        }
                    } catch (Exception e) {
        
                        logger.error(COMMON_METRICS_COLLECTOR_EXCEPTION, "", "", "error occurred when synchronize metrics collector.", e);
                    }
                }
            });
        }