Spring integration migration to Redis from RabbitMQ to share application events - spring-integration

Question

We are migrating to Redis from RabbitMQ in our microservice applications.
Here is our service activator
#ServiceActivator(inputChannel = ApplicationEventChannelNames.REMOTE_CHANNEL)
public void handleApplicationEvent(#Header(value = ApplicationEventHeaders.APPLICATION_EVENT) final ApplicationEvent event,
#Payload Object message) {
...
}
Initially we had a problem where we were losing application event in the SimpleMessageConverter. We solved it by implementing a CustomRedisMessageConverter and putting application event into the payload in the fromMessage method and retreiving it from payload and create a new message headers with application event in the toMessage method.
#Override
public Object fromMessage(Message<?> message, Class<?> targetClass) {
if (message.getHeaders().get(ApplicationEventHeaders.APPLICATION_EVENT) != null) {
Map<String, Object> map = new HashMap<>();
map.put("headers", ((ApplicationEvent) message.getHeaders().get(ApplicationEventHeaders.APPLICATION_EVENT)).getName());
map.put("payload", message.getPayload());
GenericMessage<Map<String, Object>> msg = new GenericMessage<>(map, message.getHeaders());
return super.fromMessage(msg, targetClass);
}
return super.fromMessage(message, targetClass);
}
#Override
public Message<?> toMessage(Object payload, MessageHeaders headers) {
try {
final Map<String, ?> message = new ObjectMapper().readValue((String) payload, new TypeReference<Map<String, ?>>() {});
if (message.get("headers") != null) {
final Map<String, Object> messageHeaders = new HashMap<>(headers);
messageHeaders.put(ApplicationEventHeaders.APPLICATION_EVENT, new ApplicationEvent((String) message.get("headers")));
return super.toMessage(message.get("payload"), new MessageHeaders(messageHeaders));
}
} catch (JsonProcessingException exception) {
/* Intentionally left blank */
}
return super.toMessage(payload, headers);
}
We are wondering if there is a better approach for doing this?
Lastly, payload in the service activator come as a LinkedHashMap but we want it to be an object. With RabbitMQ this was handled.
Is there any way to do the same in Redis? Or do we use headers to keep track of the type of a payload and manually convert them into an object?
UPDATE - REDIS Configuration
#Bean
public RedisInboundChannelAdapter applicationEventInboundChannelAdapter(#Value(value = "${com.xxx.xxx.xxx.integration.spring.topic}") String topic,
MessageChannel applicationEventRemoteChannel,
RedisConnectionFactory connectionFactory) {
final RedisInboundChannelAdapter inboundChannelAdapter = new RedisInboundChannelAdapter(connectionFactory);
inboundChannelAdapter.setTopics(topic);
inboundChannelAdapter.setOutputChannel(applicationEventRemoteChannel);
inboundChannelAdapter.setErrorChannel(errorChannel());
inboundChannelAdapter.setMessageConverter(new CustomRedisMessageConverter());
return inboundChannelAdapter;
}
#ServiceActivator(inputChannel = "errorChannel")
public void processError(MessageHandlingException exception) {
try {
logger.error(
"Could not process {}, got exception: {}",
exception.getFailedMessage().getPayload(),
exception.getMessage());
logger.error(
ExceptionUtils.readStackTrace(exception));
} catch (Throwable throwable) {
logger.error(
"Got {} during processing with message: {} ",
MessageHandlingException.class.getSimpleName(),
exception);
}
}
#Bean
#ServiceActivator(inputChannel = ApplicationEventChannelNames.LOCAL_CHANNEL)
public RedisPublishingMessageHandler redisPublishingMessageHandler(#Value(value = "${com.xxx.xxx.xxx.integration.spring.topic}") String topic,
RedisConnectionFactory redisConnectionFactory) {
final RedisPublishingMessageHandler redisPublishingMessageHandler = new RedisPublishingMessageHandler(redisConnectionFactory);
redisPublishingMessageHandler.setTopic(topic);
redisPublishingMessageHandler.setSerializer(new Jackson2JsonRedisSerializer<>(String.class));
redisPublishingMessageHandler.setMessageConverter(new CusomRedisMessageConverter());
return redisPublishingMessageHandler;
}
/*
* MessageChannel
*/
#Bean
public MessageChannel errorChannel() {
return new DirectChannel();
}

Answer 1

Redis does not support headers, so you have to embed them into a body. See EmbeddedJsonHeadersMessageMapper which could be supplied into that org.springframework.integration.support.converter.SimpleMessageConverter on both side.