spring cloud的ConsulCatalogWatch有什么作用

本篇内容主要讲解"spring cloud的ConsulCatalogWatch有什么作用"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"spring cloud的ConsulCatalogWatch有什么作用"吧!

序

本文主要研究一下spring cloud的ConsulCatalogWatch

ConsulCatalogWatch

spring-cloud-consul-discovery-2.1.2.RELEASE-sources.jar!/org/springframework/cloud/consul/discovery/ConsulCatalogWatch.java

public class ConsulCatalogWatch                implements ApplicationEventPublisherAware, SmartLifecycle {        private static final Log log = LogFactory.getLog(ConsulDiscoveryClient.class);        private final ConsulDiscoveryProperties properties;        private final ConsulClient consul;        private final TaskScheduler taskScheduler;        private final AtomicReference catalogServicesIndex = new AtomicReference<>();        private final AtomicBoolean running = new AtomicBoolean(false);        private ApplicationEventPublisher publisher;        private ScheduledFuture watchFuture;        public ConsulCatalogWatch(ConsulDiscoveryProperties properties, ConsulClient consul) {                this(properties, consul, getTaskScheduler());        }        public ConsulCatalogWatch(ConsulDiscoveryProperties properties, ConsulClient consul,                        TaskScheduler taskScheduler) {                this.properties = properties;                this.consul = consul;                this.taskScheduler = taskScheduler;        }        private static ThreadPoolTaskScheduler getTaskScheduler() {                ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();                taskScheduler.initialize();                return taskScheduler;        }        @Override        public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {                this.publisher = publisher;        }        @Override        public boolean isAutoStartup() {                return true;        }        @Override        public void stop(Runnable callback) {                this.stop();                callback.run();        }        @Override        public void start() {                if (this.running.compareAndSet(false, true)) {                        this.watchFuture = this.taskScheduler.scheduleWithFixedDelay(                                        this::catalogServicesWatch,                                        this.properties.getCatalogServicesWatchDelay());                }        }        @Override        public void stop() {                if (this.running.compareAndSet(true, false) && this.watchFuture != null) {                        this.watchFuture.cancel(true);                }        }        @Override        public boolean isRunning() {                return false;        }        @Override        public int getPhase() {                return 0;        }        @Timed("consul.watch-catalog-services")        public void catalogServicesWatch() {                try {                        long index = -1;                        if (this.catalogServicesIndex.get() != null) {                                index = this.catalogServicesIndex.get().longValue();                        }                        Response>> response = this.consul.getCatalogServices(                                        new QueryParams(this.properties.getCatalogServicesWatchTimeout(),                                                        index),                                        this.properties.getAclToken());                        Long consulIndex = response.getConsulIndex();                        if (consulIndex != null) {                                this.catalogServicesIndex.set(BigInteger.valueOf(consulIndex));                        }                        if (log.isTraceEnabled()) {                                log.trace("Received services update from consul: " + response.getValue()                                                + ", index: " + consulIndex);                        }                        this.publisher.publishEvent(new HeartbeatEvent(this, consulIndex));                }                catch (Exception e) {                        log.error("Error watching Consul CatalogServices", e);                }        }}

• ConsulCatalogWatch构造器接收ConsulDiscoveryProperties、ConsulClient、TaskScheduler；其start方法会使用taskScheduler.scheduleWithFixedDelay注册catalogServicesWatch的定时任务；stop方法则是cancel掉这个定时任务；catalogServicesWatch方法使用consul.getCatalogServices方法获取consulIndex然后更新本地的catalogServicesIndex，发布HeartbeatEvent

ConsulDiscoveryClientConfiguration

spring-cloud-consul-discovery-2.1.2.RELEASE-sources.jar!/org/springframework/cloud/consul/discovery/ConsulDiscoveryClientConfiguration.java

@Configuration@ConditionalOnConsulEnabled@ConditionalOnProperty(value = "spring.cloud.consul.discovery.enabled", matchIfMissing = true)@ConditionalOnDiscoveryEnabled@EnableConfigurationProperties@AutoConfigureBefore({ SimpleDiscoveryClientAutoConfiguration.class,                CommonsClientAutoConfiguration.class })public class ConsulDiscoveryClientConfiguration {        /**         * Name of the catalog watch task scheduler bean.         */        public static final String CATALOG_WATCH_TASK_SCHEDULER_NAME = "catalogWatchTaskScheduler";        @Autowired        private ConsulClient consulClient;        @Bean        @ConditionalOnMissingBean        @ConditionalOnProperty("spring.cloud.consul.discovery.heartbeat.enabled")        // TODO: move to service-registry for Edgware        public TtlScheduler ttlScheduler(HeartbeatProperties heartbeatProperties) {                return new TtlScheduler(heartbeatProperties, this.consulClient);        }        @Bean        @ConditionalOnMissingBean        // TODO: move to service-registry for Edgware        public HeartbeatProperties heartbeatProperties() {                return new HeartbeatProperties();        }        @Bean        @ConditionalOnMissingBean        // TODO: Split appropriate values to service-registry for Edgware        public ConsulDiscoveryProperties consulDiscoveryProperties(InetUtils inetUtils) {                return new ConsulDiscoveryProperties(inetUtils);        }        @Bean        @ConditionalOnMissingBean        public ConsulDiscoveryClient consulDiscoveryClient(                        ConsulDiscoveryProperties discoveryProperties) {                return new ConsulDiscoveryClient(this.consulClient, discoveryProperties);        }        @Bean        @ConditionalOnMissingBean        @ConditionalOnProperty(name = "spring.cloud.consul.discovery.catalog-services-watch.enabled", matchIfMissing = true)        public ConsulCatalogWatch consulCatalogWatch(                        ConsulDiscoveryProperties discoveryProperties,                        @Qualifier(CATALOG_WATCH_TASK_SCHEDULER_NAME) TaskScheduler taskScheduler) {                return new ConsulCatalogWatch(discoveryProperties, this.consulClient,                                taskScheduler);        }        @Bean(name = CATALOG_WATCH_TASK_SCHEDULER_NAME)        @ConditionalOnProperty(name = "spring.cloud.consul.discovery.catalog-services-watch.enabled", matchIfMissing = true)        public TaskScheduler catalogWatchTaskScheduler() {                return new ThreadPoolTaskScheduler();        }}

• ConsulDiscoveryClientConfiguration会注册ConsulCatalogWatch，其使用了名为catalogWatchTaskScheduler的taskScheduler；这里创建的是ThreadPoolTaskScheduler

小结

ConsulCatalogWatch构造器接收ConsulDiscoveryProperties、ConsulClient、TaskScheduler；其start方法会使用taskScheduler.scheduleWithFixedDelay注册catalogServicesWatch的定时任务；stop方法则是cancel掉这个定时任务；catalogServicesWatch方法使用consul.getCatalogServices方法获取consulIndex然后更新本地的catalogServicesIndex，发布HeartbeatEvent

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