Our application is storing data the user enters in SalesForce. We are using Spring AMQP (RabbitMQ) to be able to store data and run the application even if SalesForce is not reachable (scheduled downtimes or else).
So once SalesForce is not available the queue should wait with retrying messages until it is up again. Is this possible using the CircuitBreakerRetryPolicy or do i have to implement a custom RetryPolicy?
Currently i just have a simply retry policy which should be replaced by a complex one that blocks the retries until the external system is reachable again.
#Bean
RetryOperationsInterceptor salesForceInterceptor() {
return RetryInterceptorBuilder.stateless()
.recoverer(new RejectAndDontRequeueRecoverer())
.retryPolicy(simpleRetryPolicy())
.build();
}
Message listener:
#Override
public void onMessage(Message message) {
try {
.....
} catch (ResourceAccessException e) {
//TODO probablyy wrong exception
throw new AmqpTimeoutException("Salesforce can not be accessed, retry later");
} catch (Exception e) {
throw new AmqpRejectAndDontRequeueException("Fatal error with message to salesforce, do not retry", e);
}
}
Related
I am working on a worker service that consume from rabbitmq queue and I am trying to figure out how to handle channel shut down event, for example: lets say my consumer didn't ack the broker for 30 minutes and the broker shut down the channel for that.
I know the rabbitmq clinet library (I am using the C# library) will automatically try to re-connect on connection shut down, but what is the best practice for when the connection is alive but the channel was closed? I can register handler for the 'Channel Shut Down' event but what should I do inside this handler except for logging it? I want to keep consuming from the the relevant queue after all.
here is my code, i tried to create the channel again but i get timeout exception for that:
var consumer = ...
channel.BasicConsume(queue: queueName, autoAck: false, consumer: consumer);
channel.BasicQos(0, 100, false);
channel.ModelShutdown += (sender, args) =>
{
try
{
Log.Error($"channel was shut down");
channel = _connection.CreateModel();
channel.BasicConsume(queue: queueName, autoAck: false, consumer: consumer);
channel.BasicQos(0, 100, false)
}
catch (Exception exception)
{
Log.Error(exception);
}
As far as I understand, the problem is related to the fact that the event processing occurs in the same thread that is trying to access the RabbitMQ server, or there is a lock blocking the creation of the channel. The simplest solution I've found is to just use Task.Run(() => )
private async void RecreateChannel(object sender, ShutdownEventArgs e)
{
_logger.LogWarning($"Channel was shutdowned, whit reason: {e.ReplyText}, code: {e.ReplyCode}, trying to reconnect");
_channel.Dispose();
while (!_channel.IsOpen)
{
try
{
await Task.Run(() => _channel = InitChannel());
}
catch (Exception exception)
{
_logger.LogError(exception, "Failed to recreate channel, trying again");
}
}
_logger.LogInformation("Channel was recreated successfully");
}
I have a scenario where I want to "pull" messages of a RabbitMQ queue/topic and process them one at a time.
Specifically if there are already messages sitting on the queue when the consumer starts up.
I have tried the following with no success (meaning, each of these options reads the queue until it is either empty or until another thread closes the context).
1.Stopping route immediately it is first processed
final CamelContext context = new DefaultCamelContext();
try {
context.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
RouteDefinition route = from("rabbitmq:harley?queue=IN&declare=false&autoDelete=false&hostname=localhost&portNumber=5672");
route.process(new Processor() {
Thread stopThread;
#Override
public void process(final Exchange exchange) throws Exception {
String name = exchange.getIn().getHeader(Exchange.FILE_NAME_ONLY, String.class);
String body = exchange.getIn().getBody(String.class);
// Doo some stuff
routeComplete[0] = true;
if (stopThread == null) {
stopThread = new Thread() {
#Override
public void run() {
try {
((DefaultCamelContext)exchange.getContext()).stopRoute("RabbitRoute");
} catch (Exception e) {}
}
};
}
stopThread.start();
}
});
}
});
context.start();
while(!routeComplete[0].booleanValue())
Thread.sleep(100);
context.stop();
}
Similar to 1 but using a latch rather than a while loop and sleep.
Using a PollingConsumer
final CamelContext context = new DefaultCamelContext();
context.start();
Endpoint re = context.getEndpoint(srcRoute);
re.start();
try {
PollingConsumer consumer = re.createPollingConsumer();
consumer.start();
Exchange exchange = consumer.receive();
String bb = exchange.getIn().getBody(String.class);
consumer.stop();
} catch(Exception e){
String mm = e.getMessage();
}
Using a ConsumerTemplate() - code similar to above.
I have also tried enabling preFetch and setting the max number of exchanges to 1.
None of these appear to work, if there are 3 messages on the queue, all are read before I am able to stop the route.
If I were to use the standard RabbitMQ Java API I would use a basicGet() call which lets me read a single message, but for other reasons I would prefer to use a Camel consumer.
Has anyone successfully been able to process a single message on a queue that holds multiple messages using a Camel RabbitMQ Consumer?
Thanks.
This is not the primary intention of the component as its for continued received. But I have created a ticket to look into supporting a basicGet (single receive). There is a new spring based rabbitmq component coming in 3.8 onwards so its going to be implemeneted there (first): https://issues.apache.org/jira/browse/CAMEL-16048
I am using camel-rabbitmq.
Here is my route defination
camelContext.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
from("rabbitmq:TEST?queue=TEST&concurrentConsumers=5")
.routeId("jms")
.autoStartup(false)
.throttle(10)
.asyncDelayed()
.log("Consuming message ${body} to ${header.deliveryAddress}")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
System.out.println(atomicLong.decrementAndGet());
}
})
;
}
});
When I push 500 messages to this queue , when stop and start route all message on channel will be lost ,wonder where they are going.
If I configure same route with &autoAck=false it is working properly but losing performance. Why camel not offering same behavior with and without autoAck.
I managed my problem doing following change in rabbitmqconsumer of camel-rabbitmq
public void handleCancelOk(String consumerTag) {
// no work to do
log.info("Received cancelOk signal on the rabbitMQ channel");
**downLatch.countDown();**
}
#Override
protected void doStop() throws Exception {
if (channel == null) {
return;
}
this.requeueChannel=openChannel(consumer.getConnection());
if (tag != null && isChannelOpen()) {
channel.basicCancel(tag);
}
stopping=true;
downLatch.await();
try {
lock.acquire();
if (isChannelOpen()) {
channel.close();
}
} catch (TimeoutException e) {
log.error("Timeout occured");
throw e;
} catch (InterruptedException e1) {
log.error("Thread Interrupted!");
} finally {
lock.release();
}
}
By doing this camel route will for message to consumed and avoided message loss.
You need to check rabbitmq consumer prefetch count
consumer prefetch
I think By default consumer picks all the messages in queue to its memory buffers.
If you set the prefetch count to 1, consumer will acknowledge messages one by one.
All the other unacknowledged will be present in the queue in ready state. Waiting to be picked up, after the consumer completes it task on the previous message picked.
I am new about ActiveMQ. I'm trying to study and check how it works by checking the example code provided by Apache at this link:-
http://activemq.apache.org/how-should-i-implement-request-response-with-jms.html
public class Server implements MessageListener {
private static int ackMode;
private static String messageQueueName;
private static String messageBrokerUrl;
private Session session;
private boolean transacted = false;
private MessageProducer replyProducer;
private MessageProtocol messageProtocol;
static {
messageBrokerUrl = "tcp://localhost:61616";
messageQueueName = "client.messages";
ackMode = Session.AUTO_ACKNOWLEDGE;
}
public Server() {
try {
//This message broker is embedded
BrokerService broker = new BrokerService();
broker.setPersistent(false);
broker.setUseJmx(false);
broker.addConnector(messageBrokerUrl);
broker.start();
} catch (Exception e) {
System.out.println("Exception: "+e.getMessage());
//Handle the exception appropriately
}
//Delegating the handling of messages to another class, instantiate it before setting up JMS so it
//is ready to handle messages
this.messageProtocol = new MessageProtocol();
this.setupMessageQueueConsumer();
}
private void setupMessageQueueConsumer() {
ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(messageBrokerUrl);
Connection connection;
try {
connection = connectionFactory.createConnection();
connection.start();
this.session = connection.createSession(this.transacted, ackMode);
Destination adminQueue = this.session.createQueue(messageQueueName);
//Setup a message producer to respond to messages from clients, we will get the destination
//to send to from the JMSReplyTo header field from a Message
this.replyProducer = this.session.createProducer(null);
this.replyProducer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
//Set up a consumer to consume messages off of the admin queue
MessageConsumer consumer = this.session.createConsumer(adminQueue);
consumer.setMessageListener(this);
} catch (JMSException e) {
System.out.println("Exception: "+e.getMessage());
}
}
public void onMessage(Message message) {
try {
TextMessage response = this.session.createTextMessage();
if (message instanceof TextMessage) {
TextMessage txtMsg = (TextMessage) message;
String messageText = txtMsg.getText();
response.setText(this.messageProtocol.handleProtocolMessage(messageText));
}
//Set the correlation ID from the received message to be the correlation id of the response message
//this lets the client identify which message this is a response to if it has more than
//one outstanding message to the server
response.setJMSCorrelationID(message.getJMSCorrelationID());
//Send the response to the Destination specified by the JMSReplyTo field of the received message,
//this is presumably a temporary queue created by the client
this.replyProducer.send(message.getJMSReplyTo(), response);
} catch (JMSException e) {
System.out.println("Exception: "+e.getMessage());
}
}
public static void main(String[] args) {
new Server();
}
}
My confusion about the messageBrokerUrl = "tcp://localhost:61616"; You know ActiveMQ service is running on port 61616 by default. Why does this example chooses same port. If I try to run the code thows eception as:
Exception: Failed to bind to server socket: tcp://localhost:61616 due to: java.net.BindException: Address already in use: JVM_Bind
Perhaps if I change the port number, I can execute the code.
Please let me know why it is like this in the example and how to work with BrokerService.
The BrokerService in this example is trying to create an in memory ActiveMQ broker for use in the example. Given the error you are seeing I'd guess you already have an ActiveMQ broker running on the machine that is bound to port 61616 as that's the default port and thus the two are conflicting. You could either stop the external broker and run the example or modify the example to not run the embedded broker and just rely on your external broker instance.
Embedded brokers are great for unit testing or for creating examples that don't require the user to have a broker installed and running.
I'm using rabbitmq java client 2.4.1 the newest version.
After a TCP connection lost, and still call a method on a channel over
this connection, a AlreadyClosedException will be thrown.
Is it a bug? I expected an IOException, but AlreadyClosedException I
got, and AlreadyClosedException is a RuntimeException.
If not, why all other errors cause an IOException.
#Test
public void testConnectionLost() throws IOException{
ConnectionFactory factory = new ConnectionFactory();
factory.setRequestedHeartbeat(60);
factory.setHost("<your rabbitmq host>");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
connection.close();
try {
channel.queueDeclare("queueName", false, false, false, null);
Assert.fail("Exception expected.");
}catch (IOException e) {
//it will NOT reach here.
//Inner exception should be AlreadyClosedException
System.out.println(e);
}catch (AlreadyClosedException e) {
// it will reach here.
System.out.println(e);
//this is strange!
//I expected IOException , but AlreadyClosedException I got.
//And AlreadyClosedException is a RuntimeException.
}
Thank you.
If your client loses the TCP connection to your broker, the connection is considered "closed". Therefore it is appropriate (and not a bug) for the client library to throw an AlreadyClosedException.
In other words, a connection is considered "closed" no matter how it got closed (either through a graceful manner or through an unexpected failure).