I have written spring cloud stream application listening to Kinesis streams
Message Flow across channel
Kinesis Input --> Transformer --> Router (route to error or actaul processor)
I am planning to write error handling across these channels. Currently I am explicitly catching the error and sending to different channels. Instead of catching and modifying the payload, I would like to implement generi exception handler
Binder
public interface Binder {
@Input(ITEM_KINESIS_INPUT)
SubscribableChannel itemMessage();
}
Configuration
@Configuration
@EnableIntegration
public class IntegrationConfiguration {
@Bean(name = DEFAULT_ITEM_LISTENER)
public MessageChannel defaultItemChannel() {
return new DirectChannel();
}
@Bean(name = DEFAULT_ERROR)
public MessageChannel DEFAULT_ERROR() {
return new DirectChannel();
}
@Bean
@Transformer(inputChannel = ITEM_KINESIS_INPUT, outputChannel = ITEM_TRANSFORMER)
public ItemTransformer itemTransformer() {
return new ItemTransformer();
}
@ServiceActivator(inputChannel = ITEM_TRANSFORMER)
@Bean
public ItemMessageTypeRouter router() {
return new ItemMessageTypeRouter();
}
// I tried this as well Not working
@ServiceActivator(inputChannel = "errorChannel")
@Bean
public AbstractMessageHandler process() {
return new AbstractMessageHandler() {
@Override
protected void handleMessageInternal(Message<?> message1) throws Exception {
System.out.println("MessageHandler SA");
}
};
}
}
Transformer
public class ItemTransformer extends AbstractTransformer {
@Override
public String getComponentType() {
return "transformer";
}
@Override
protected Object doTransform(Message<?> message) throws Exception {
Object transformedPayload = null;
try {
//transform
} catch (Exception e) {
transformedPayload =
new MessageTransformationException(message, "failed to transform message", e);
}
return MessageBuilder.withPayload(transformedPayload).copyHeaders(message.getHeaders()).build();
}
}
And in Router routing to different channel for error
public class ItemMessageTypeRouter extends AbstractMappingMessageRouter {
@Override
protected List<Object> getChannelKeys(Message<?> message) {
return (message.getPayload() instanceof Throwable) ? Arrays.asList(DEFAULT_ERROR)
: Arrays.asList(DEFAULT_ITEM_LISTENER)
}
}
Error Handling
@EnableBinding(Binder.class)
public class ErrorListener implements MessageListener<Message> {
@Autowired
private MessagesBackupRepository backupRepository;
@Override
@StreamListener(DEFAULT_ERROR)
public void receiveMessage(Message message) {
log.error("Error has been reported " + message);
}
}
Can we implement generic exception handler all these channels.
Currently I only handle error in Transformer, but if there is any exception occurs in Router or later channels, then this also needs to handled manually
Any insight for better error handling
