使用shedlock將spring schedule上鎖

序

本文講述如何使用shedlock給spring schedule上鎖，保證集羣內部調度任務不會重複執行，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，這裏使用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();
    }
}

這裏使用了jdbc的lock provider，同時設定默認最大的lock expire時間爲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)
)

這個須要手工創建，不過能夠優化一下，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");
    }

doc

• ShedLock