序
本文講述如何使用shedlock給spring schedule上鎖，保證集群內部調度任務不會重復執行，避免資源浪費。
maven
<dependency>
<groupId>net.javacrumbs.shedlock</groupId>
<artifactId>shedlock-spring</artifactId>
<version>0.16.1</version>
</dependency>
<dependency>
<groupId>net.javacrumbs.shedlock</groupId>
<artifactId>shedlock-provider-jdbc-template</artifactId>
<version>0.16.1</version>
</dependency>
shedlock提供了mongo、redis、zookeeper、jdbc等的鎖實現，這里使用jdbc。
shedlock配置
@Configuration
@EnableScheduling
public class ShedlockConfig {
@Bean
public LockProvider lockProvider(DataSource dataSource) {
return new JdbcTemplateLockProvider(dataSource);
}
@Bean
public ScheduledLockConfiguration scheduledLockConfiguration(LockProvider lockProvider) {
return ScheduledLockConfigurationBuilder
.withLockProvider(lockProvider)
.withPoolSize(10)
.withDefaultLockAtMostFor(Duration.ofMinutes(10))
.build();
}
}
這里使用了jdbc的lock provider，同時設定默認最大的lock expire時間為10分鐘
shedlock表
CREATE TABLE shedlock(
name VARCHAR(64),
lock_until TIMESTAMP(3) NULL,
locked_at TIMESTAMP(3) NULL,
locked_by VARCHAR(255),
PRIMARY KEY (name)
)
這個需要手工建立，不過可以優化一下，自動建表。
實例
@Scheduled(fixedDelay = 10*1000 /**ms**/,initialDelay = 10*1000)
@SchedulerLock(name = "demoLockTask", lockAtMostFor = 5*1000)
public void checkTask(){
LOGGER.error("checkTask executed");
}
