Persist issue with a spring batch ItemWriter using a JPA repository

Question

I have an issue with a spring batch ItemWriter that relies on a JPA repository in order to update data.

Here it is:

@Component
public class MessagesDigestMailerItemWriter implements ItemWriter<UserAccount> {

    private static final Logger log = LoggerFactory.getLogger(MessagesDigestMailerItemWriter.class);

    @Autowired
    private MessageRepository messageRepository;

    @Autowired
    private MailerService mailerService;

    @Override
    public void write(List<? extends UserAccount> userAccounts) throws Exception {
        log.info("Mailing messages digests and updating messages notification statuses");

        for (UserAccount userAccount : userAccounts) {
            if (userAccount.isEmailNotification()) {
                mailerService.mailMessagesDigest(userAccount);
            }
            for (Message message : userAccount.getReceivedMessages()) {
                message.setNotificationSent(true);
                messageRepository.save(message);//NOT SAVING!!
            }
        }
    }
}

Here is my Step configuration:

@Configuration
public class MailStepConfiguration {

    @Autowired
    private StepBuilderFactory stepBuilderFactory;

    @Autowired
    private EntityManagerFactory entityManagerFactory;

    @Autowired
    private MessagesDigestMailerItemWriter itemWriter;

    @Bean
    public Step messagesDigestMailingStep() {
        return stepBuilderFactory.get("messagesDigestMailingStep")//
                .<UserAccount, UserAccount> chunk(1)//
                .reader(jpaPagingItemReader(entityManagerFactory))//
                .writer(itemWriter)//
                .build();
    }

    @Bean(destroyMethod = "")
    @StepScope
    public static ItemReader<UserAccount> jpaPagingItemReader(EntityManagerFactory entityManagerFactory) {
        final JpaPagingItemReader<UserAccount> reader = new JpaPagingItemReader<>();
        reader.setEntityManagerFactory(entityManagerFactory);
        reader.setQueryString("SELECT ua FROM UserAccount ua JOIN FETCH ua.receivedMessages msg WHERE msg.notificationSent = false AND msg.messageRead = false");
        return reader;
    }

}

For completeness sake, here is my spring boot configuration:

@Configuration
@EnableBatchProcessing
@EnableAutoConfiguration
@ComponentScan("com.bignibou.batch.configuration")
public class Batch {
    public static void main(String[] args) {
        System.exit(SpringApplication.exit(new SpringApplicationBuilder(Batch.class).web(false).run(args)));
    }
}

and my datasource config:

@Configuration
@EnableJpaRepositories({ "com.bignibou.repository" })
@EntityScan("com.bignibou.domain")
public class DatasourceConfiguration {

    @Bean
    @ConfigurationProperties("spring.datasource.batch")
    public DataSource batchDatasource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
    @Primary
    @ConfigurationProperties("spring.datasource.application")
    public DataSource applicationDatasource() {
        return DataSourceBuilder.create().build();
    }
}

I noticed that the execution flow get into the ItemWriter's write method and the messageRepository.save(message); does get executed but the data is not updated.

I suspect it is a transaction issue but I am not sure how to solve this problem...

edit: I forgot to mention that I have two Postgres databases:

1. one for the job repository data
2. another one for the application data.

I can confirm that data is written into the job repository database. The issue is with the application data. I am required to use distributed transactions bearing in mind the fact that I have two PG databases?

Answer 1

I opened an issue for this here:

https://jira.spring.io/browse/BATCH-2642

In principle, what helped us was to configure primary transaction manager like so:

@Configuration
public class JpaConfig {

    private final DataSource dataSource;

    @Autowired
    public JpaConfig(@Qualifier("dataSource") DataSource dataSource) {
        this.dataSource = dataSource;
    }

    @Bean
    @Primary
    public JpaTransactionManager jpaTransactionManager() {
        final JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setDataSource(dataSource);
        return transactionManager;
    }

}

And then using autowired instance of transaction manager when configuring the step, like so:

@Autowired
private PlatformTransactionManager transactionManager;

private TaskletStep buildTaskletStep() {
        return stepBuilderFactory.get("SendCampaignStep")
                    .<UserAccount, UserAccount>chunk(pushServiceConfiguration.getCampaignBatchSize())
                    .reader(userAccountItemReader)
                    .processor(userAccountItemProcessor)
                    .writer(userAccountItemWriter)
                    .transactionManager(transactionManager)
                    .build();
    }
}

Data is now correctly persisted, but there is still some magic I don't fully get...