spring cloud consul中TtlScheduler的原理和作用是什么
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本文主要研究一下spring cloud consul的TtlScheduler
TtlScheduler
spring-cloud-consul-discovery-2.1.2.RELEASE-sources.jar!/org/springframework/cloud/consul/discovery/TtlScheduler.java
public class TtlScheduler { private static final Log log = LogFactory.getLog(ConsulDiscoveryClient.class); private final Map<String, ScheduledFuture> serviceHeartbeats = new ConcurrentHashMap<>(); private final TaskScheduler scheduler = new ConcurrentTaskScheduler( Executors.newSingleThreadScheduledExecutor()); private HeartbeatProperties configuration; private ConsulClient client; public TtlScheduler(HeartbeatProperties configuration, ConsulClient client) { this.configuration = configuration; this.client = client; } @Deprecated public void add(final NewService service) { add(service.getId()); } /** * Add a service to the checks loop. * @param instanceId instance id */ public void add(String instanceId) { ScheduledFuture task = this.scheduler.scheduleAtFixedRate( new ConsulHeartbeatTask(instanceId), this.configuration .computeHearbeatInterval().toStandardDuration().getMillis()); ScheduledFuture previousTask = this.serviceHeartbeats.put(instanceId, task); if (previousTask != null) { previousTask.cancel(true); } } public void remove(String instanceId) { ScheduledFuture task = this.serviceHeartbeats.get(instanceId); if (task != null) { task.cancel(true); } this.serviceHeartbeats.remove(instanceId); } private class ConsulHeartbeatTask implements Runnable { private String checkId; ConsulHeartbeatTask(String serviceId) { this.checkId = serviceId; if (!this.checkId.startsWith("service:")) { this.checkId = "service:" + this.checkId; } } @Override public void run() { TtlScheduler.this.client.agentCheckPass(this.checkId); if (log.isDebugEnabled()) { log.debug("Sending consul heartbeat for: " + this.checkId); } } } }
TtlScheduler的构造器接收HeartbeatProperties、ConsulClient;add方法会往scheduler注册一个定时执行的ConsulHeartbeatTask,执行间隔由HeartbeatProperties的ttlValue及intervalRatio计算而来,同时如果previousTask不为null则对其进行cancel;remove方法则cancel调用ScheduledFuture,然后将其从serviceHeartbeats中移除;ConsulHeartbeatTask的run方法则是执行client.agentCheckPass
HeartbeatProperties
spring-cloud-consul-discovery-2.1.2.RELEASE-sources.jar!/org/springframework/cloud/consul/discovery/HeartbeatProperties.java
@ConfigurationProperties(prefix = "spring.cloud.consul.discovery.heartbeat") @Validated public class HeartbeatProperties { private static final Log log = org.apache.commons.logging.LogFactory .getLog(HeartbeatProperties.class); // TODO: change enabled to default to true when I stop seeing messages like // [WARN] agent: Check 'service:testConsulApp:xtest:8080' missed TTL, is now critical boolean enabled = false; @Min(1) private int ttlValue = 30; @NotNull private String ttlUnit = "s"; @DecimalMin("0.1") @DecimalMax("0.9") private double intervalRatio = 2.0 / 3.0; // TODO: did heartbeatInterval need to be a field? protected Period computeHearbeatInterval() { // heartbeat rate at ratio * ttl, but no later than ttl -1s and, (under lesser // priority), no sooner than 1s from now double interval = this.ttlValue * this.intervalRatio; double max = Math.max(interval, 1); int ttlMinus1 = this.ttlValue - 1; double min = Math.min(ttlMinus1, max); Period heartbeatInterval = new Period(Math.round(1000 * min)); log.debug("Computed heartbeatInterval: " + heartbeatInterval); return heartbeatInterval; } public String getTtl() { return this.ttlValue + this.ttlUnit; } public boolean isEnabled() { return this.enabled; } public void setEnabled(boolean enabled) { this.enabled = enabled; } public @Min(1) int getTtlValue() { return this.ttlValue; } public void setTtlValue(@Min(1) int ttlValue) { this.ttlValue = ttlValue; } public @NotNull String getTtlUnit() { return this.ttlUnit; } public void setTtlUnit(@NotNull String ttlUnit) { this.ttlUnit = ttlUnit; } public @DecimalMin("0.1") @DecimalMax("0.9") double getIntervalRatio() { return this.intervalRatio; } public void setIntervalRatio( @DecimalMin("0.1") @DecimalMax("0.9") double intervalRatio) { this.intervalRatio = intervalRatio; } @Override public String toString() { return new ToStringCreator(this).append("enabled", this.enabled) .append("ttlValue", this.ttlValue).append("ttlUnit", this.ttlUnit) .append("intervalRatio", this.intervalRatio).toString(); } }
HeartbeatProperties有ttlValue、intervalRatio等属性,其computeHearbeatInterval方法会取ttlMinus1及Math.max(interval, 1)的最小值作为heartbeatInterval
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在@ConditionalOnMissingBean以及@ConditionalOnProperty("spring.cloud.consul.discovery.heartbeat.enabled")的条件下会自动注册ttlScheduler
小结
TtlScheduler的构造器接收HeartbeatProperties、ConsulClient;add方法会往scheduler注册一个定时执行的ConsulHeartbeatTask,执行间隔由HeartbeatProperties的ttlValue及intervalRatio计算而来,同时如果previousTask不为null则对其进行cancel;remove方法则cancel调用ScheduledFuture,然后将其从serviceHeartbeats中移除;ConsulHeartbeatTask的run方法则是执行client.agentCheckPass
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