@RefreshScope stops @Scheduled task

Question

I have a monitoring app wherein I am running a fixedRate task. This is pulling in a config parameter configured with Consul. I want to pull in updated configuration, so I ad

Answer 1

My solution consists of listening to EnvironmentChangeEvent

@Configuration
public class SchedulingSpringConfig implements ApplicationListener, SchedulingConfigurer {

  private static final Logger LOGGER = LoggerFactory.getLogger(SchedulingSpringConfig.class);

  private final DemoProperties demoProperties;

  public SchedulingSpringConfig(DemoProperties demoProperties) {
    this.demoProperties = demoProperties;
  }

  @Override
  public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
    LOGGER.info("Configuring scheduled task with cron expression: {}", demoProperties.getCronExpression());
    taskRegistrar.addTriggerTask(triggerTask());
    taskRegistrar.setTaskScheduler(taskScheduler());
  }

  @Bean
  public TriggerTask triggerTask() {
    return new TriggerTask(this::work, cronTrigger());
  }

  private void work() {
    LOGGER.info("Doing work!");
  }

  @Bean
  @RefreshScope
  public CronTrigger cronTrigger() {
    return new CronTrigger(demoProperties.getCronExpression());
  }

  @Bean
  public ThreadPoolTaskScheduler taskScheduler() {
    return new ThreadPoolTaskScheduler();
  }

  @Override
  public void onApplicationEvent(EnvironmentChangeEvent event) {
    if (event.getKeys().contains("demo.config.cronExpression")) {
      ScheduledTasksRefresher scheduledTasksRefresher = new ScheduledTasksRefresher(triggerTask());
      scheduledTasksRefresher.afterPropertiesSet();
    }
  }
}

Then I use the ContextLifecycleScheduledTaskRegistrar to recreate the task.

public class ScheduledTasksRefresher extends ContextLifecycleScheduledTaskRegistrar {

  private final TriggerTask triggerTask;

  ScheduledTasksRefresher(TriggerTask triggerTask) {
    this.triggerTask = triggerTask;
  }

  @Override
  public void afterPropertiesSet() {
    super.destroy();
    super.addTriggerTask(triggerTask);
    super.afterSingletonsInstantiated();
  }
}

Properties definition:

@ConfigurationProperties(prefix = "demo.config", ignoreUnknownFields = false)
public class DemoProperties {

  private String cronExpression;

  public String getCronExpression() {
    return cronExpression;
  }

  public void setCronExpression(String cronExpression) {
    this.cronExpression = cronExpression;
  }
}

Main definition:

@SpringBootApplication
@EnableConfigurationProperties(DemoProperties.class)
@EnableScheduling
public class DemoApplication {

  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }
}