Spring Integration: MQTT integration test basics - spring

Question

I try to test a simple MQTT listener created with Spring Boot and Spring Integration, but don't get it working. I've tried many approaches. The most promising was:
#RunWith(SpringRunner.class)
#SpringBootTest
public class BasicMqttTest {
#Value("${mqtt.client.id}")
private String mqttClientId;
#Value("${mqtt.state.topic}")
private String mqttTopic;
#Autowired
MqttPahoClientFactory mqttPahoClientFactory;
protected IMqttClient client;
#Before
public void setUp() throws Exception {
client = mqttPahoClientFactory.getClientInstance(mqttPahoClientFactory.getConnectionOptions().getServerURIs()[0], mqttClientId);
client.connect();
}
#After
public void tearDown() throws Exception {
client.disconnect();
client.close();
}
#Test
public void contextLoads() throws Exception {
MqttMessage mqttMessage = new MqttMessage();
mqttMessage.setPayload("MQTT!".getBytes());
client.publish(mqttTopic, mqttMessage);
}
}
However, the test runs with
2018-07-12 16:53:50.937 ERROR 21160 --- [T Rec: consumer] .m.i.MqttPahoMessageDrivenChannelAdapter : Lost connection: Verbindung wurde getrennt; retrying...
, and I don't see anything printed out.
The code is mostly from: https://github.com/spring-projects/spring-integration-samples/tree/master/basic/mqtt
. The example works nicely, but I need to be able to write proper integration tests.
The configuration is:
#Value("${mqtt.server.uri}")
private String mqttServerUri;
#Value("${mqtt.username}")
private String mqttUsername;
#Value("${mqtt.password}")
private String mqttPassword;
#Value("${mqtt.client.id}")
private String mqttClientId;
#Value("${mqtt.state.topic}")
private String mqttTopic;
#Value("${mqtt.completion.timeout}")
private Integer mqttCompletionTimeout;
#Value("${mqtt.quality.of.service}")
private Integer mqttQualityOfService;
#Bean
public MqttPahoClientFactory mqttClientFactory() {
DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
MqttConnectOptions options = new MqttConnectOptions();
options.setServerURIs(new String[]{mqttServerUri});
options.setUserName(mqttUsername);
options.setPassword(mqttPassword.toCharArray());
factory.setConnectionOptions(options);
return factory;
}
#Bean
#Qualifier("MqttInboundChannel")
public MessageProducerSupport mqttInbound() {
MqttPahoMessageDrivenChannelAdapter adapter = new MqttPahoMessageDrivenChannelAdapter(
mqttClientId,
mqttClientFactory(),
mqttTopic
);
adapter.setCompletionTimeout(mqttCompletionTimeout);
adapter.setConverter(new DefaultPahoMessageConverter());
adapter.setQos(mqttQualityOfService);
return adapter;
}
#Bean
public IntegrationFlow myMqttInFlow() {
return IntegrationFlows.from(mqttInbound)
.handle(message -> {
System.out.println(message);
}).get();
}
UPDATE:
Didn't work either:
#Autowired
protected MessageHandler mqttOutbound;
#Test
public void test0() throws Exception {
mqttOutbound.handleMessage(MessageBuilder.withPayload("test").build());
}
#SpringBootApplication
static class MqttSourceApplication {
#Autowired
private MqttPahoClientFactory mqttClientFactory;
#Bean
public MessageHandler mqttOutbound() {
MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler("test", mqttClientFactory);
messageHandler.setAsync(true);
messageHandler.setDefaultTopic("test");
messageHandler.setConverter(pahoMessageConverter());
return messageHandler;
}
#Bean
public DefaultPahoMessageConverter pahoMessageConverter() {
DefaultPahoMessageConverter converter = new DefaultPahoMessageConverter(1, false, "UTF-8");
return converter;
}
}
UPDATE
Even simpler ... same error:
#Autowired
MqttPahoClientFactory mqttPahoClientFactory;
private MessageHandler mqttOutbound;
#Before
public void setUp() throws Exception {
MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler(mqttClientId, mqttPahoClientFactory);
messageHandler.setAsync(false);
messageHandler.setDefaultTopic(mqttTopic);
messageHandler.setConverter(new DefaultPahoMessageConverter());
mqttOutbound = messageHandler;
}
#Test
public void test0() throws Exception {
mqttOutbound.handleMessage(MessageBuilder.withPayload("test").build());
Thread.sleep(10000L);
}

Answer 1

Ok, resolved: Paho apparently closed my connection since both the test and main used the same client id. The solution was to replace the clientId with MqttAsyncClient.generateClientId() as suggested here: https://stackoverflow.com/a/48232793/2739681