How to set the override on a compound trigger?

问题

I have a Spring integration application that normally polls daily for a file via SFTP using a cron trigger. But if it doesn't find the file it expects, it should poll every x minutes via a periodic trigger until y attempts. To do this I use the following component:

@Component
public class RetryCompoundTriggerAdvice extends AbstractMessageSourceAdvice {

    private final static Logger logger = LoggerFactory.getLogger(RetryCompoundTriggerAdvice.class);

    private final CompoundTrigger compoundTrigger;

    private final Trigger override;

    private final ApplicationProperties applicationProperties;

    private final Mail mail;

    private int attempts = 0;

    public RetryCompoundTriggerAdvice(CompoundTrigger compoundTrigger, 
            @Qualifier("secondaryTrigger") Trigger override, 
            ApplicationProperties applicationProperties,
            Mail mail) {
        this.compoundTrigger = compoundTrigger;
        this.override = override;
        this.applicationProperties = applicationProperties;
        this.mail = mail;
    }

    @Override
    public boolean beforeReceive(MessageSource<?> source) {
        return true;
    }

    @Override
    public Message<?> afterReceive(Message<?> result, MessageSource<?> source) {
        final int  maxOverrideAttempts = applicationProperties.getMaxFileRetry();
        attempts++;
        if (result == null && attempts < maxOverrideAttempts) {
            logger.info("Unable to find load file after " + attempts + " attempt(s). Will reattempt");
            this.compoundTrigger.setOverride(this.override);
        } else if (result == null && attempts >= maxOverrideAttempts) {
            mail.sendAdminsEmail("Missing File");
            attempts = 0;
            this.compoundTrigger.setOverride(null);
        }
        else {
            attempts = 0;
            this.compoundTrigger.setOverride(null);
            logger.info("Found load file");
        }
        return result;
    }

    public void setOverrideTrigger() {
        this.compoundTrigger.setOverride(this.override);
    }

    public CompoundTrigger getCompoundTrigger() {
        return compoundTrigger;
    }
}

If a file doesn't exist, this works great. That is, the override (i.e. periodic trigger) takes effect and polls every x minutes until y attempts.

However, if a file does exist but it's not the expected file (e.g. the data is at the wrong date), another class (that reads the file) calls the setOverrideTrigger of the RetryCompoundTriggerAdvice class. But afterReceive is not subsequently called at every x minutes. Why would this be?

Here's more of the application code:

SftpInboundFileSynchronizer:

@Bean
public SftpInboundFileSynchronizer sftpInboundFileSynchronizer() {
    SftpInboundFileSynchronizer fileSynchronizer = new SftpInboundFileSynchronizer(sftpSessionFactory());
    fileSynchronizer.setDeleteRemoteFiles(false);
    fileSynchronizer.setRemoteDirectory(applicationProperties.getSftpDirectory());
    CompositeFileListFilter<ChannelSftp.LsEntry> compositeFileListFilter = new CompositeFileListFilter<ChannelSftp.LsEntry>();
    compositeFileListFilter.addFilter(new SftpPersistentAcceptOnceFileListFilter(store, "sftp"));
    compositeFileListFilter.addFilter(new SftpSimplePatternFileListFilter(applicationProperties.getLoadFileNamePattern()));
    fileSynchronizer.setFilter(compositeFileListFilter);
    fileSynchronizer.setPreserveTimestamp(true);
    return fileSynchronizer;
}

Session factory is:

@Bean
public SessionFactory<LsEntry> sftpSessionFactory() {
    DefaultSftpSessionFactory sftpSessionFactory = new DefaultSftpSessionFactory();
    sftpSessionFactory.setHost(applicationProperties.getSftpHost());
    sftpSessionFactory.setPort(applicationProperties.getSftpPort());
    sftpSessionFactory.setUser(applicationProperties.getSftpUser());
    sftpSessionFactory.setPassword(applicationProperties.getSftpPassword());
    sftpSessionFactory.setAllowUnknownKeys(true);
    return new CachingSessionFactory<LsEntry>(sftpSessionFactory);
}

The SftpInboundFileSynchronizingMessageSource is set to poll using the compound trigger.

@Bean
@InboundChannelAdapter(autoStartup="true", channel = "sftpChannel", poller = @Poller("pollerMetadata"))
public SftpInboundFileSynchronizingMessageSource sftpMessageSource() {
    SftpInboundFileSynchronizingMessageSource source =
            new SftpInboundFileSynchronizingMessageSource(sftpInboundFileSynchronizer());
    source.setLocalDirectory(applicationProperties.getScheduledLoadDirectory());
    source.setAutoCreateLocalDirectory(true);
    CompositeFileListFilter<File> compositeFileFilter = new CompositeFileListFilter<File>();
    compositeFileFilter.addFilter(new LastModifiedFileListFilter());
    compositeFileFilter.addFilter(new FileSystemPersistentAcceptOnceFileListFilter(store, "dailyfilesystem"));
    source.setLocalFilter(compositeFileFilter);
    source.setCountsEnabled(true);
    return source;
}

@Bean
public PollerMetadata pollerMetadata(RetryCompoundTriggerAdvice retryCompoundTriggerAdvice) {
    PollerMetadata pollerMetadata = new PollerMetadata();
    List<Advice> adviceChain = new ArrayList<Advice>();
    adviceChain.add(retryCompoundTriggerAdvice);
    pollerMetadata.setAdviceChain(adviceChain);
    pollerMetadata.setTrigger(compoundTrigger());
    pollerMetadata.setMaxMessagesPerPoll(1);
    return pollerMetadata;
}

@Bean
public CompoundTrigger compoundTrigger() {
    CompoundTrigger compoundTrigger = new CompoundTrigger(primaryTrigger());
    return compoundTrigger;
}

@Bean
public CronTrigger primaryTrigger() {
    return new CronTrigger(applicationProperties.getSchedule());
}

@Bean
public PeriodicTrigger secondaryTrigger() {
    return new PeriodicTrigger(applicationProperties.getRetryInterval());
}

Update

Here's the message handler:

@Bean
@ServiceActivator(inputChannel = "sftpChannel")
public MessageHandler dailyHandler(SimpleJobLauncher jobLauncher, Job job, Mail mail) {
    JobRunner jobRunner = new JobRunner(jobLauncher, job, store, mail);
    jobRunner.setDaily("true");
    jobRunner.setOverwrite("false");
    return jobRunner;
}

JobRunner kicks off a Spring Batch job. After processing the job, my application looks to see if the file had the data it expected for the day. If not, it is setting the override trigger.

回答1:

That's the way triggers work - you only get an opportunity to change the trigger when the trigger fires.

Since you reset to the cron trigger, the next opportunity for change is when that trigger fires (if the poller thread is released by the downstream flow before changing the trigger).

Are you handing off the file to another thread (queue channel or executor)? If not, I would expect any changes to the trigger should be applied, because nextExecutionTime() will not be called until the downstream flow returns.

If there's a thread handoff, you have no opportunity to change the trigger.

来源：https://stackoverflow.com/questions/42404440/how-to-set-the-override-on-a-compound-trigger