TCP Client Spring Integration with Java Config - spring

Question

I am attempting to create a TCP client to connect to a remote tcp server and wait to receive messages. So far I have the following code:
#EnableIntegration
#IntegrationComponentScan
#Configuration
public class TcpClientConfig {
#Bean
public TcpInboundGateway tcpInbound(AbstractClientConnectionFactory connectionFactory) {
TcpInboundGateway gate = new TcpInboundGateway();
gate.setConnectionFactory(connectionFactory);
gate.setClientMode(false);
gate.setRequestChannel(fromTcp());
return gate;
}
#Bean
public MessageChannel fromTcp() {
return new DirectChannel();
}
#MessageEndpoint
public static class Echo {
#Transformer(inputChannel = "fromTcp", outputChannel = "serviceChannel")
public String convert(byte[] bytes) {
return new String(bytes);
}
}
#ServiceActivator(inputChannel = "serviceChannel")
public void messageToService(String in) {
System.out.println(in);
}
#Bean
public EndOfLineSerializer endOfLineSerializer() {
return new EndOfLineSerializer();
}
#Bean
public AbstractClientConnectionFactory clientConnectionFactory() {
TcpNetClientConnectionFactory tcpNetServerConnectionFactory = new TcpNetClientConnectionFactory("192.XXX.XXX.XX", 4321);
tcpNetServerConnectionFactory.setSingleUse(false);
tcpNetServerConnectionFactory.setSoTimeout(300000);
tcpNetServerConnectionFactory.setDeserializer(endOfLineSerializer());
tcpNetServerConnectionFactory.setSerializer(endOfLineSerializer());
tcpNetServerConnectionFactory.setMapper(new TimeoutMapper());
return tcpNetServerConnectionFactory;
}
}
It starts up and connects to the remote server. However, I am not receiving any data in my serviceActivator method messageToService. To assure that data exists, I can successfully connect to my remote tcp server using telnet
telnet 192.XXX.XXX.XX 4321
Trying 192.XXX.XXX.XX...
Connected to 192.XXX.XXX.XX.
Escape character is '^]'.
Hello World
I have confirmed nothing is hitting my EndOfLineSerializer. What is wrong with my TCP client?
Bonus: Let's assume the hostname and port are determined by querying an API. How would I tell the TcpNetClientConnectionFactory to wait to try to connect until I have the correct data for the port?
Debug output:
main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-11-22 23:00:46.182 DEBUG 35953 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Autodetecting user-defined JMX MBeans
2018-11-22 23:00:46.194 DEBUG 35953 --- [ main] .s.i.c.GlobalChannelInterceptorProcessor : No global channel interceptors.
2018-11-22 23:00:46.198 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase -2147483648
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : Adding {logging-channel-adapter:_org.springframework.integration.errorLogger} as a subscriber to the 'errorChannel' channel
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.channel.PublishSubscribeChannel : Channel 'application.errorChannel' has 1 subscriber(s).
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : started _org.springframework.integration.errorLogger
2018-11-22 23:00:46.198 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Successfully started bean '_org.springframework.integration.errorLogger'
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : Adding {service-activator:tcpClientConfig.messageToService.serviceActivator} as a subscriber to the 'serviceChannel' channel
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.integration.channel.DirectChannel : Channel 'application.serviceChannel' has 1 subscriber(s).
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : started tcpClientConfig.messageToService.serviceActivator
2018-11-22 23:00:46.198 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Successfully started bean 'tcpClientConfig.messageToService.serviceActivator'
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : Adding {transformer:tcpClientConfig.Echo.convert.transformer} as a subscriber to the 'toTcp' channel
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.integration.channel.DirectChannel : Channel 'application.toTcp' has 1 subscriber(s).
2018-11-22 23:00:46.198 INFO 35953 --- [ main] o.s.i.endpoint.EventDrivenConsumer : started tcpClientConfig.Echo.convert.transformer
2018-11-22 23:00:46.198 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Successfully started bean 'tcpClientConfig.Echo.convert.transformer'
2018-11-22 23:00:46.198 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 0
2018-11-22 23:00:46.199 INFO 35953 --- [ main] .s.i.i.t.c.TcpNetClientConnectionFactory : started clientConnectionFactory, host=192.XXX.XXX.90, port=4321
2018-11-22 23:00:46.199 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Successfully started bean 'clientConnectionFactory'
2018-11-22 23:00:46.199 INFO 35953 --- [ main] .s.i.i.t.c.TcpNetClientConnectionFactory : started clientConnectionFactory, host=192.XXX.XXX.90, port=4321
2018-11-22 23:00:46.199 INFO 35953 --- [ main] o.s.i.ip.tcp.TcpInboundGateway : started tcpInbound
2018-11-22 23:00:46.199 DEBUG 35953 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Successfully started bean 'tcpInbound'

Answer 1

When using a client connection factory with an inbound endpoint there is no stimulus to open a connection (client factories are normally used for outbound operations and the connection is established when the first message is sent).
When used in this mode, you need setClientMode(true). This starts a task that opens (and monitors) an outbound connection.
See the documentation
Normally, inbound adapters use a type="server" connection factory, which listens for incoming connection requests. In some cases, you may want to establish the connection in reverse, such that the inbound adapter connects to an external server and then waits for inbound messages on that connection.
This topology is supported by setting client-mode="true" on the inbound adapter. In this case, the connection factory must be of type client and must have single-use set to false.
Two additional attributes support this mechanism. retry-interval specifies (in milliseconds) how often the framework attempts to reconnect after a connection failure. scheduler supplies a TaskScheduler to schedule the connection attempts and to test that the connection is still active.
(The framework provides a default scheduler).
For your Bonus question, you would need to find the host/port before creating the application context; or create the connection factory and gateway dynamically after you have the information.