Develop Reference

I can't send message using google pubsub emulator in spring boot

I'm trying to send push message using the emulator of pubsub, I'm using spring boot too, this is my configuration:
Dependency:
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-gcp-starter-pubsub</artifactId>
</dependency>
My bean:
#Configuration
#AutoConfigureBefore(value= GcpPubSubAutoConfiguration.class)
#EnableConfigurationProperties(value= GcpPubSubProperties.class)
public class EmulatorPubSubConfiguration {
#Value("${spring.gcp.pubsub.projectid}")
private String projectId;
#Value("${spring.gcp.pubsub.subscriptorid}")
private String subscriptorId;
#Value("${spring.gcp.pubsub.topicid}")
private String topicId;
#Bean
public Publisher pubsubEmulator() throws IOException {
String hostport = System.getenv("PUBSUB_EMULATOR_HOST");
ManagedChannel channel = ManagedChannelBuilder.forTarget(hostport).usePlaintext().build();
try {
TransportChannelProvider channelProvider =
FixedTransportChannelProvider.create(GrpcTransportChannel.create(channel));
CredentialsProvider credentialsProvider = NoCredentialsProvider.create();
// Set the channel and credentials provider when creating a `TopicAdminClient`.
// Similarly for SubscriptionAdminClient
TopicAdminClient topicClient =
TopicAdminClient.create(
TopicAdminSettings.newBuilder()
.setTransportChannelProvider(channelProvider)
.setCredentialsProvider(credentialsProvider)
.build());
ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
// Set the channel and credentials provider when creating a `Publisher`.
// Similarly for Subscriber
return Publisher.newBuilder(topicName)
.setChannelProvider(channelProvider)
.setCredentialsProvider(credentialsProvider)
.build();
} finally {
channel.shutdown();
}
}
}
Of course, I have set PUBSUB_EMULATOR_HOST system variable to localhost:8085, where is the emulator running
I created a rest controller for testing:
for send push message
#Autowired
private Publisher pubsubPublisher;
#PostMapping("/send1")
public String publishMessage(#RequestParam("message") String message) throws InterruptedException, IOException {
Publisher pubsubPublisher = this.getPublisher();
ByteString data = ByteString.copyFromUtf8(message);
PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();
ApiFuture<String> future = pubsubPublisher.publish(pubsubMessage);
//pubsubPublisher.publishAllOutstanding();
try {
// Add an asynchronous callback to handle success / failure
ApiFutures.addCallback(future,
new ApiFutureCallback<String>() {
#Override
public void onFailure(Throwable throwable) {
if (throwable instanceof ApiException) {
ApiException apiException = ((ApiException) throwable);
// details on the API exception
System.out.println(apiException.getStatusCode().getCode());
System.out.println(apiException.isRetryable());
}
System.out.println("Error publishing message : " + message);
System.out.println("Error publishing error : " + throwable.getMessage());
System.out.println("Error publishing cause : " + throwable.getCause());
}
#Override
public void onSuccess(String messageId) {
// Once published, returns server-assigned message ids (unique within the topic)
System.out.println(messageId);
}
},
MoreExecutors.directExecutor());
}
finally {
if (pubsubPublisher != null) {
// When finished with the publisher, shutdown to free up resources.
pubsubPublisher.shutdown();
pubsubPublisher.awaitTermination(1, TimeUnit.MINUTES);
}
}
return "ok";
for get message:
#PostMapping("/pushtest")
public String pushTest(#RequestBody CloudPubSubPushMessage request) {
System.out.println( "------> message received: " + decode(request.getMessage().getData()) );
return request.toString();
}
I have created my topic and subscription in the emulator, I followed this tutorial:
https://cloud.google.com/pubsub/docs/emulator
I'm set the endpoint "pushtest" for get push message in the emulator, with this command:
python subscriber.py PUBSUB_PROJECT_ID create-push TOPIC_ID SUBSCRIPTION_ID PUSH_ENDPOINT
But when I run the test, doesn't reach "/pushtest" endpoint and I'm getting this error:
Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask#265d5d05
[Not completed, task = java.util.concurrent.Executors$RunnableAdapter#a8c8be3
[Wrapped task = com.google.common.util.concurrent.TrustedListenableFutureTask#1a53c57c
[status=PENDING, info=[task=[running=[NOT STARTED YET], com.google.api.gax.rpc.AttemptCallable#3866e1d0]]]]]
rejected from java.util.concurrent.ScheduledThreadPoolExecutor#3f34809a
[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 1]
for assurance that the emulator is running ok, I'm run the test in python with the following command:
python publisher.py PUBSUB_PROJECT_ID publish TOPIC_ID
And I'm getting messages correctly in "pushtest" endpoint.
I don't know why sorry for my hazing.
Thanks for your help.

I found the problem.
Only comment this line in the bean
channel.shutdown();
HAHA very simple.

How to access the payload of the message arrived of the callback method (messageArrived) in the main method Eclipse Paho?

Problem statement:- I am trying to automate a MQTT flow, for that I a need to publish and subscribe to multiple topics but in a sequential order. The trick part is that the message received from the first publish has some value which will be passed in the next sub/pub commands.
For eg.
Sub to topicA/abc
Pub to topicA/abc
Message received on topicA/abc is xyz
sub to topic topicA/xyz
pub to topic topicA/xyz
I am able to receive the message on the first topic but I am not getting how to access the payload of the received message in the main method and pass and attach it to the next topic for next sub.
Is there a way to get the retrieved the message payload from messageArrived callback method to the main method where is client instance is created?
Note:- I am using a single client for publish and subscribe.
kindly help me out as I have ran out of options and methods to do so.
Edited:-
Code snippet
Main class
public class MqttOverSSL {
String deviceId;
MqttClient client = null;
public MqttOverSSL() {
}
public MqttOverSSL(String deviceId) throws MqttException, InterruptedException {
this.deviceId = deviceId;
MqttConnection mqttConObj = new MqttConnection();
this.client = mqttConObj.mqttConnection();
}
public void getLinkCodeMethod() throws MqttException, InterruptedException {
client.subscribe("abc/multi/" + deviceId + "/linkcode", 0);
publish(client, "abc/multi/" + deviceId + "/getlinkcode", 0, "".getBytes());
}
}
Mqtt Claback impl:-
public class SimpleMqttCallBack implements MqttCallback {
String arrivedMessage;
#Override
public void connectionLost(Throwable throwable) {
System.out.println("Connection to MQTT broker lost!");
}
#Override
public void messageArrived(String s, MqttMessage mqttMessage) throws Exception {
arrivedMessage = mqttMessage.toString();
System.out.println("Message received:\t" + arrivedMessage);
linkCode(arrivedMessage);
}
#Override
public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
System.out.println("Delivery complete callback: Publish Completed "+ Arrays.toString(iMqttDeliveryToken.getTopics()));
}
public void linkCode(String arrivedMessage) throws MqttException {
System.out.println("String is "+ arrivedMessage);
Gson g = new Gson();
GetCode code = g.fromJson(arrivedMessage, GetCode.class);
System.out.println(code.getLinkCode());
}
}
Publisher class:-
public class Publisher {
public static void publish(MqttClient client, String topicName, int qos, byte[] payload) throws MqttException {
String time = new Timestamp(System.currentTimeMillis()).toString();
log("Publishing at: "+time+ " to topic \""+topicName+"\" qos "+qos);
// Create and configure a message
MqttMessage message = new MqttMessage(payload);
message.setQos(qos);
// Send the message to the server, control is not returned until
// it has been delivered to the server meeting the specified
// quality of service.
client.publish(topicName, message);
}
static private void log(String message) {
boolean quietMode = false;
if (!quietMode) {
System.out.println(message);
}
}
}

OK, it's a little clearer what you are trying to do now.
Short answer No, you can not pass values back to the "main method". MQTT is asynchronous that means you have no idea when a message will arrive for a topic you subscribe to.
You need to update your code to deal check what the incoming message topic is and then deal do what ever action you wanted to do with that response in the messageArrived() handler. If you have a sequence of task to do then you may need to implement what is known as a state machine in order to keep track of where you are in the sequence.

Read without removing message from JMS queue

How to read a message from WebSphere MQ without deleting the original message from queue?
I have spring application which reads the message from the WebSphere MQ.
After reading, I have a process method which will process the data retrieved from queue.
Step 1:
response = jmsTemplate.receive();
//Message automatically removed from queue.
Step 2:
process(response);
There are chances of throwing exceptions in process method. In case of exceptions, I need to retain the message in the queue.
Is it possible? Is their any way to delete the message only on user acknowledgement?
I tried adding the following:
jmsTemplate.setSessionAcknowledgeMode(javax.jms.Session.CLIENT_ACKNOWLEDGE);
...but still the message is getting deleted.
JmsTemplate creating code snippet:
JndiConnectionFactorySupport connectionFactoryBean = new JndiConnectionFactorySupport();
connectionFactoryBean.setBindingsDir(this.bindingDir);
connectionFactoryBean
.setConnectionFactoryName(connectionFactoryName);
connectionFactoryBean.afterPropertiesSet();
jmsTemplate.setConnectionFactory(connectionFactoryBean.getObject());
JndiDestinationResolver destinationResolver = new JndiDestinationResolver();
destinationResolver.setJndiTemplate(connectionFactoryBean
.getJndiTemplate());
jmsTemplate.setDestinationResolver(destinationResolver);
jmsTemplate.setReceiveTimeout(20000);
jmsTemplate.setDefaultDestinationName(this.defaultDestinationName);
Tried the jmsTemplate.execute() method as below:
#SuppressWarnings({ "unused", "unchecked" })
Message responseMessage = (Message) jmsTemplate.execute(
new SessionCallback() {
public Object doInJms(Session session)
throws JMSException {
MessageConsumer consumer = session
.createConsumer(jmsTemplate.getDestinationResolver().resolveDestinationName(session, "QUEUE_NAME", false));
Message response = consumer.receive(1);
try {
testMethod();//this method will throw exception.
response.acknowledge();
consumer.close();
} catch(Exception e){
consumer.close();//control will come here.
}
return response;
}
}, true);

You can't do that with receive() methods because the operation is complete (from the session perspective) when the receive method returns.
You need to run the code that might fail within the scope of the session; e.g. with a JmsTemplate.execute() with a SessionCallback - something like this...
this.jmsTemplate.setSessionAcknowledgeMode(Session.CLIENT_ACKNOWLEDGE);
this.jmsTemplate.convertAndSend("foo", "bar");
try {
String value = this.jmsTemplate.execute(session -> {
MessageConsumer consumer = session.createConsumer(
this.jmsTemplate.getDestinationResolver().resolveDestinationName(session, "foo", false));
String result;
try {
Message received = consumer.receive(5000);
result = (String) this.jmsTemplate.getMessageConverter().fromMessage(received);
// Do some stuff that might throw an exception
received.acknowledge();
}
finally {
consumer.close();
}
return result;
}, true);
System.out.println(value);
}
catch (Exception e) {
e.printStackTrace();
}

You have to browse the queue.
Example of real code that was executed making usage of Websphere MQ
public void browseMessagesAndJiraCreation(String jiraUserName, String jiraPassword) {
int counterMessages = jmsTemplate.browse(destinationQueueName, new BrowserCallback<Integer>() {
#Override
public Integer doInJms(final Session session, final QueueBrowser queueBrowser) throws JMSException {
Enumeration<TextMessage> enumeration = queueBrowser.getEnumeration();
int counterMessages = 0;
while (enumeration.hasMoreElements()) {
counterMessages += 1;
TextMessage msg = enumeration.nextElement();
logger.info("Found : {}", msg.getText());
JiraId jiraId = jiraManager.createIssue(jiraUserName, jiraPassword);
jiraManager.attachFileToJira(jiraId, msg.getText(), jiraUserName, jiraPassword);
}
return counterMessages;
}
});
logger.info("{}:messages were browsed and processed from queue:{}.", counterMessages, destinationQueueName);
}
Explanations:
usage of the Spring Framework JmsTemplate
you pass the String gestinationQueueName (example destinationQueueName=QL.PREFCNTR.USER.REPLY)
Java enumeration of Text messages
counterMessages is the counter of messages that were processed
messages are NOT consumed!

You can add transactional processing of JMS messages. See the example
Your listener should be "transacted". Like this
<jms:listener-container connection-factory="connectionFactory" acknowledge="transacted">
<jms:listener ref="notificationProcessor" destination="incoming.queue"/>
</jms:listener-container>

Cloudhopper SMPP - How to get messages content which have sent from other clients?

I have downloaded the source from github from this link: https://github.com/twitter/cloudhopper-smpp
Assuming I want to test receiving message between clients so I create a server and 2 clients. To run server, I used the command "make server". Then in other machine, a client connected to my server and send 1 message to other client which has phone number "123456" using following code
submit0.setSourceAddress(new Address((byte)0x03, (byte)0x00, "654321"));
submit0.setDestAddress(new Address((byte)0x01, (byte)0x01, "123456"));
submit0.setShortMessage(textBytes);
SubmitSmResp submitResp = session0.submit(submit0, 10000);
How can the client which has phone number "123456" get message content from phone number "654321"?
Thanks!

When you are creating sessionHandler like this,
DefaultSmppSessionHandler sessionHandler = new ClientSmppSessionHandler();
This ClientSmppSessionHandler should be extended to DefaultSmppSessionHandler.
There are 2 listeners.
Please see below example.
public class ClientSmppSessionHandler extends DefaultSmppSessionHandler {
private static final Logger logger = LoggerFactory.getLogger(ClientSmppSessionHandler.class);
public ClientSmppSessionHandler() {
super(logger);
}
#Override
public void firePduRequestExpired(PduRequest pduRequest) {
logger.warn("PDU request expired: {}", pduRequest);
}
#Override
public PduResponse firePduRequestReceived(PduRequest pduRequest) {
PduResponse response = pduRequest.createResponse();
logger.info("SMS Received: {}", pduRequest);
if (pduRequest.getCommandId() == SmppConstants.CMD_ID_DELIVER_SM) {
DeliverSm mo = (DeliverSm) pduRequest;
int length = mo.getShortMessageLength();
Address source_address = mo.getSourceAddress();
Address dest_address = mo.getDestAddress();
byte[] shortMessage = mo.getShortMessage();
String SMS= new String(shortMessage);
logger.info(source_address + ", " + dest_address + ", " + SMS);
}
return response;
}
}

switch Tibco RV to WebSphere MQ?

My application is listening to Tibco RV, now I am required to switch to WebSphere MQ. I found the code like this
Tibrv.open(Tibrv.IMPL_NATIVE);
rvdTransport = new TibrvRvdTransport(...);
TibrvQueue queue = new TibrvQueue();
cmqTransport = new TibrvCmQueueTransport(...);
queueListener = new TibrvCmListener(...);
disp = new TibrvDispatcher(...)
In the MQ side, do we have similar concepts?
Thanks

Short answer - Yes.
When you download and install the WMQ client (SupportPac MQC71) you get, in addition to the Java classes, diagnostic utilities and lots of sample code. Among the sample programs you will find MQSample.java which looks like this:
import com.ibm.mq.MQException;
import com.ibm.mq.MQGetMessageOptions;
import com.ibm.mq.MQMessage;
import com.ibm.mq.MQPutMessageOptions;
import com.ibm.mq.MQQueue;
import com.ibm.mq.MQQueueManager;
import com.ibm.mq.constants.MQConstants;
public class MQSample {
public static void main(String args[]) {
try {
// Create a connection to the QueueManager
System.out.println("Connecting to queue manager: " + qManager);
MQQueueManager qMgr = new MQQueueManager(qManager);
// Set up the options on the queue we wish to open
int openOptions = MQConstants.MQOO_INPUT_AS_Q_DEF | MQConstants.MQOO_OUTPUT;
// Now specify the queue that we wish to open and the open options
System.out.println("Accessing queue: " + qName);
MQQueue queue = qMgr.accessQueue(qName, openOptions);
// Define a simple WebSphere MQ Message ...
MQMessage msg = new MQMessage();
// ... and write some text in UTF8 format
msg.writeUTF("Hello, World!");
// Specify the default put message options
MQPutMessageOptions pmo = new MQPutMessageOptions();
// Put the message to the queue
System.out.println("Sending a message...");
queue.put(msg, pmo);
// Now get the message back again. First define a WebSphere MQ
// message
// to receive the data
MQMessage rcvMessage = new MQMessage();
// Specify default get message options
MQGetMessageOptions gmo = new MQGetMessageOptions();
// Get the message off the queue.
System.out.println("...and getting the message back again");
queue.get(rcvMessage, gmo);
// And display the message text...
String msgText = rcvMessage.readUTF();
System.out.println("The message is: " + msgText);
// Close the queue
System.out.println("Closing the queue");
queue.close();
// Disconnect from the QueueManager
System.out.println("Disconnecting from the Queue Manager");
qMgr.disconnect();
System.out.println("Done!");
}
catch (MQException ex) {
System.out.println("A WebSphere MQ Error occured : Completion Code " + ex.completionCode
+ " Reason Code " + ex.reasonCode);
ex.printStackTrace();
for (Throwable t = ex.getCause(); t != null; t = t.getCause()) {
System.out.println("... Caused by ");
t.printStackTrace();
}
}
catch (java.io.IOException ex) {
System.out.println("An IOException occured whilst writing to the message buffer: " + ex);
}
return;
}
}
There are of course also samples for JMS, C, C#, etc. The sample shown uses synchronous (blocking) GET calls but there are async listener methods if you want to implement with a callback mechanism.
I would also recommend looking over the application development sections of the Infocenter. These are the v7.0 docs and these are the v7.1 docs.