CODEWITHSUNDEEP
springspring-boot
Arya
Arya

Reputation: 8995

Spring async ConcurrentTaskExecutor not really working correctly?

It's my first time working with Async in Spring boot. Here is how my project is structured.

I have the following ExecutorConfig class

@Configuration
@EnableAsync
public class ExecutorConfig {
    @Bean(name = "ConcurrentTaskExecutor")
    public Executor getAsyncExecutor() {
        return new ConcurrentTaskExecutor(Executors.newFixedThreadPool(10));
    }
}

This following class which will be called with @Scheduled 

@Component
public class RealtyTracCountyScraper {

    @Autowired
    StateScrapeQueueRepository stateScrapeQueueRepository;

    @Autowired
    CountyScrapeRepository countyScrapeRepository;

    @Autowired
    CountyScraper countyScraper;

    // @Scheduled(cron = "0 0 */3 * * *")
    @EventListener(ApplicationReadyEvent.class)
    public void scrapeCountyLinks() {
        System.out.println("Scrape county links ran!");
        try {
            List<String> stateLinks = stateScrapeQueueRepository.getStatesLinks("");

            for (int i = 0; i < stateLinks.size(); i++) {
                countyScraper.run(stateLinks.get(i));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            System.out.println("---------------------");
        }
    }

}

and this class which gets called from the class above (This is the class that contains the multithreaded method)

@Component
public class CountyScraper implements AsyncConfigurer {

    @Autowired
    StateScrapeQueueRepository stateScrapeQueueRepository;

    @Autowired
    CountyScrapeRepository countyScrapeRepository;

    @Async("ConcurrentTaskExecutor")
    public void run(String stateLink) {
        System.out.println("New thread");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Done");

    }
}

Even though I have set 10 fixed threads in the ExecutorConfig class, it looks like only one thread works at a time. Any idea what I am doing wrong?

Upvotes: 2

Views: 2947

Answers (1)

M. Deinum
M. Deinum

Reputation: 125202

I guess there are a couple of things not completely right in your code.

  1. Your component implements AsyncConfigurer
  2. You don't have @EnableScheduling

Your CountyScraper implements the AsyncConfigurer interface. Leading to 2 possible problems. The first is configuring async processing with the defaults and usage of interface based proxies instead of class based proxies. Hence eliminating the @Async. Although the latter doesn't seem to be the case, one might never know.

The AsyncConfigurer should actually be implemented by your ExecutorConfig. 

@Configuration
@EnableAsync
@EnableScheduling
public class ExecutorConfig implements AsyncConfigurer {

    public Executor getAsyncExecutor() {
        return taskExecutor();
    }

    @Bean
    public ThreadPoolTaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new TaskExecutor();
        taskExecutor.setCorePoolSize(10);
        return taskExecutor;
    }
}

This will configure the default Executor used for async processing. Instead of a ConcurrentTaskExecutor I used the ThreadPoolTaskExecutor instead. The latter allows a bit more configuration and will cleanup the threads nicely when Spring Boot shutsdown.

TIP: If you are using Spring Boot 2.1 you can actually ditch the configuration of the TaskExecutor and replace it with configuration only.

Now you can use a simple @Async instead of naming the executor explicitly (which will now fail because it is named differently). 

spring.task.execution.pool.core-size=10 # Default is 8

Your configuration then becomes 

@Configuration
@EnableAsync
@EnableScheduling
public class ExecutorConfig {}

Upvotes: 5

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