How to get a file daily via SFTP using Spring Integration with Java config? - spring-integration

Question

I need to get a file daily via SFTP. I would like to use Spring Integration with Java config. The file is generally available at a specific time each day. The application should try to get the file near that time each day. If the file is not available, it should continue to retry for x attempts. After x attempts, it should send an email to let the admin know that the file is still not available on the SFTP site.
One option is to use SftpInboundFileSynchronizingMessageSource. In the MessageHandler, I can kick off a job to process the file. However, I really don't need synchronization with the remote file system. After all, it is a scheduled delivery of the file. Plus, I need to delay at most 15 minutes for the next retry and to poll every 15 minutes seems a bit overkill for a daily file. I guess that I could use this but would need some mechanism to send email after a certain time elapsed and no file was received.
The other option seems to be using get of the SFTP Outbound Gateway. But the only examples I can find seem to be XML config.
Update
Adding code after using help provided by Artem Bilan's answer below:
Configuration class:
#Bean
#InboundChannelAdapter(autoStartup="true", channel = "sftpChannel", poller = #Poller("pollerMetadata"))
public SftpInboundFileSynchronizingMessageSource sftpMessageSource(ApplicationProperties applicationProperties, PropertiesPersistingMetadataStore store) {
SftpInboundFileSynchronizingMessageSource source =
new SftpInboundFileSynchronizingMessageSource(sftpInboundFileSynchronizer(applicationProperties));
source.setLocalDirectory(new File("ftp-inbound"));
source.setAutoCreateLocalDirectory(true);
FileSystemPersistentAcceptOnceFileListFilter local = new FileSystemPersistentAcceptOnceFileListFilter(store,"test");
source.setLocalFilter(local);
source.setCountsEnabled(true);
return source;
}
#Bean
public PollerMetadata pollerMetadata() {
PollerMetadata pollerMetadata = new PollerMetadata();
List<Advice> adviceChain = new ArrayList<Advice>();
adviceChain.add(retryCompoundTriggerAdvice());
pollerMetadata.setAdviceChain(adviceChain);
pollerMetadata.setTrigger(compoundTrigger());
return pollerMetadata;
}
#Bean
public RetryCompoundTriggerAdvice retryCompoundTriggerAdvice() {
return new RetryCompoundTriggerAdvice(compoundTrigger(), secondaryTrigger());
}
#Bean
public CompoundTrigger compoundTrigger() {
CompoundTrigger compoundTrigger = new CompoundTrigger(primaryTrigger());
return compoundTrigger;
}
#Bean
public Trigger primaryTrigger() {
return new CronTrigger("*/60 * * * * *");
}
#Bean
public Trigger secondaryTrigger() {
return new PeriodicTrigger(10000);
}
#Bean
#ServiceActivator(inputChannel = "sftpChannel")
public MessageHandler handler(PropertiesPersistingMetadataStore store) {
return new MessageHandler() {
#Override
public void handleMessage(Message<?> message) throws MessagingException {
System.out.println(message.getPayload());
store.flush();
}
};
}
RetryCompoundTriggerAdvice class:
public class RetryCompoundTriggerAdvice extends AbstractMessageSourceAdvice {
private final CompoundTrigger compoundTrigger;
private final Trigger override;
private int count = 0;
public RetryCompoundTriggerAdvice(CompoundTrigger compoundTrigger, Trigger overrideTrigger) {
Assert.notNull(compoundTrigger, "'compoundTrigger' cannot be null");
this.compoundTrigger = compoundTrigger;
this.override = overrideTrigger;
}
#Override
public boolean beforeReceive(MessageSource<?> source) {
return true;
}
#Override
public Message<?> afterReceive(Message<?> result, MessageSource<?> source) {
if (result == null && count <= 5) {
count++;
this.compoundTrigger.setOverride(this.override);
}
else {
this.compoundTrigger.setOverride(null);
if (count > 5) {
//send email
}
count = 0;
}
return result;
}
}

Answer 1

Since Spring Integration 4.3 there is CompoundTrigger:
* A {#link Trigger} that delegates the {#link #nextExecutionTime(TriggerContext)}
* to one of two Triggers. If the {#link #setOverride(Trigger) override} trigger is
* {#code null}, the primary trigger is invoked; otherwise the override trigger is
* invoked.
With the combination of CompoundTriggerAdvice:
* An {#link AbstractMessageSourceAdvice} that uses a {#link CompoundTrigger} to adjust
* the poller - when a message is present, the compound trigger's primary trigger is
* used to determine the next poll. When no message is present, the override trigger is
* used.
it can be used to reach your task:
The primaryTrigger can be a CronTrigger to run the task only once a day.
The override could be a PeriodicTrigger with desired short period to retry.
The retry logic you can utilize with one more Advice for poller or just extend that CompoundTriggerAdvice to add count logic to send an email eventually.
Since there is no file, therefore no message to kick the flow. And we don't have choice unless dance around the poller infrastructure.