I would like to setup Shedlock to guard a sensitive process so that only ONE instance of the process ever runs even when multiple application processes are started.
In my pom.xml
<dependency>
<groupId>net.javacrumbs.shedlock</groupId>
<artifactId>shedlock-spring</artifactId>
</dependency>
<dependency>
<groupId>net.javacrumbs.shedlock</groupId>
<artifactId>shedlock-provider-jdbc-template</artifactId>
</dependency>
My DB:
CREATE TABLE shedlock(
name VARCHAR(64) NOT NULL,
lock_until TIMESTAMP NOT NULL,
locked_at TIMESTAMP NOT NULL,
locked_by VARCHAR(255) NOT NULL,
PRIMARY KEY (name));
My configuration:
@Configuration
@EnableScheduling
public class ShedlockConfiguration {
@Bean
public LockProvider lockProvider(DataSource dataSource) {
return new JdbcTemplateLockProvider(
JdbcTemplateLockProvider.Configuration.builder()
.withJdbcTemplate(new JdbcTemplate(dataSource))
.usingDbTime()
.build()
);
}
}
My schedule:
@Component
public class SchedulerA {
@Scheduled(initialDelayString = "${examples.scheduler.initial-delay:PT1S}",
fixedDelayString = "${examples.scheduler.fixed-delay:PT10S}")
@SchedulerLock(name = "example_scheduler",
lockAtLeastFor = "${examples.scheduler.lock-at-least:PT5S}",
lockAtMostFor = "${examples.scheduler.lock-at-most:PT30S}")
public void schedule() {
// Implementation not important
}
}
Symptom: If I start only one instance with multiple SchedulerA classes like SchedulerB, SchedulerC, etc which are all copies of the same code I can see the Shedlock does its thing and only allow one LOCAL instance to execute at a time. But, when I start up multiple Spring Boot applications, they all their schedules concurrently even when they use the same DB, same table, same scheduler name. I also notice no entries in the DB table, but the debug logs also reveals no errors.
Question: Is this the expected behaviour of Shedlock? Should I research another solution or did I misconfigured something?
You need to add @EnableSchedulerLock to your configuration class as per documents : "In order to enable schedule locking use @EnableSchedulerLock annotation"