I am working with ActiveMQ in C#. I do not understand how to set the Redelivery Policy in code. I have tried to set the property in code on consumer side, but I am not able to understand whether it is working or not.
RedeliveryPolicy policy = connection.RedeliveryPolicy
policy.InitialRedeliveryDelay = 50000;
policy.MaximumRedeliveries = 5;
Above I have set the property, but I don't know it is right way or not.
It should be connection.getRedeliveryPolicy();
Below is a simple example of settings:
RedeliveryPolicy policy = connection.getRedeliveryPolicy();
policy.setInitialRedeliveryDelay(500);
policy.setBackOffMultiplier(2);
policy.setUseExponentialBackOff(true);
policy.setMaximumRedeliveries(2);
Related
I was currently using NMS to develop application based ActiveMQ(5.6).
We have several consumers(exe) trying to recieving massgaes from the same queue(not topic). While all the messages just all go to one consumer though I have make the consumer to sleep for seconds after recieving a message. By the way, we don't want the consumers recieving the same messages other consumers have recieved.
It is mentioned in the official website that we should set Prefetch Limit to decide how many messages can be streamed to a consumer at any point in time. And it can both be configured and coded.
One way I tried is to code using PrefetchPolicy class binding the ConnectionFactory class like bellow.
PrefetchPolicy poli = new PrefetchPolicy();
poli.QueuePrefetch = 0;
ConnectionFactory fac = new ConnectionFactory("activemq:tcp://Localhost:61616?jms.prefetchPolicy.queuePrefetch=1");
fac.PrefetchPolicy = poli;
using (IConnection con = fac.CreateConnection())
{
using (ISession se = con.CreateSession())
{
IDestination destination = SessionUtil.GetDestination(se, queue, DestinationType.Queue);
using (IMessageConsumer consumer = se.CreateConsumer(queue1))
{
con.Start();
while (true)
{
ITextMessage message = consumer.Receive() as ITextMessage;
Thread.Sleep(2000);
if (message != null)
{
Task.Factory.StartNew(() => extractAndSend(message.Text)); //do something
}
else
{
Console.WriteLine("No message received~");
}
}
}
}
}
But no matter what prefetch value I set the behavior of the consumers stay the same as before.
And I've tried the second way tying to get the result, namely configure the server conf file. I change the activemq.xml of the server like bellow.
" producerFlowControl="true" memoryLimit="5mb" />
" producerFlowControl="true" memoryLimit="5mb">
But though I've set the dispatchpolicy the messages still go to one consumer.
I want to know that:
Whether this behavior can be achieved by just configuring the server xml file to enable all the consumers recieve messages from one queue? If so, how to configure this and what is wrong with my configuration? If not, how can I use codes to achieve the goal?
Thanks.
Take a look at "Message Groups" feature.
I had the same problem. Only one consumer processed all messages. I found in my code I used group header during send:
request.Properties["NMSXGroupID"] = "cheese";
According to official docs:
Standard JMS header JMSXGroupID is used to define which message group
the message belongs to. The Message Group feature then ensures that
all messages for the same message group will be sent to the same JMS
consumer - while that consumer stays alive. As soon as the consumer
dies another will be chosen.
See full details at http://activemq.apache.org/message-groups.html
I need to remove/delete my topic subscriber. I found this http://activemq.apache.org/manage-durable-subscribers.html
However, it's not good enough for us. We want to control the timing of removing a subscriber, and no matter there are any message or not. Besides, our program is written by C#. So the best solution for us is NMS API.
Thanks.
Here are the code,
Apache.NMS.ActiveMQ.ConnectionFactory factory = new Apache.NMS.ActiveMQ.ConnectionFactory(m_brokerURI);
m_connection = factory.CreateConnection(username, password);
Apache.NMS.ActiveMQ.Connection con = (Apache.NMS.ActiveMQ.Connection)m_connection;
ISession session = m_connection.CreateSession(AcknowledgementMode.AutoAcknowledge);
try
{
session.DeleteDurableConsumer(strQueueName);
}
catch (Exception ex)
{
// log the error message
}
Update
Our scenario is quite simple.
A client built a queue and subscribed a consumer on a topic.
the client side closed the connection.
delete the consumer on the server side(as the example code in the last update)
Here is the snapshot of activemq broker via jconsole:
jconsole snapshot
We would like to remove the subscriber “7B0FD84D-6A2A-4921-967F-92B215E22751” by following method,
But always got this error "javax.jms.InvalidDestinationException : No durable subscription exists for: 7B0FD84D-6A2A-4921-967F-92B215E22751"
strSubscriberName = “7B0FD84D-6A2A-4921-967F-92B215E22751”
session.DeleteDurableConsumer(strSubscriberName);
To delete a durable subscription from the NMS API you use the DeleteDurableConsumer method defined in ISession. You must call this method from a Connection that uses the same client Id as was used when the subscription was created and you pass the name of the subscription that is to be removed. The method will fail if there is an active subscriber though so be prepared for that exception.
In the sample code you don't set a Client Id on the connection. When working with durable subscriptions you must, must, MUST always use the same client Id and subscription name. So in you same you will get this error until you set the client Id to the same value as the connection that created the subscription in the first place.
I am trying to figure out how to implement session management in wso2 esb.So i have written a class mediator which generates session_ID that i want to store.For storing the session id I am using following code as:
org.apache.axis2.context.ServiceContext serviceContext = org.apache.axis2.context.MessageContext
.getCurrentMessageContext().getServiceContext();
serviceContext.setProperty("SessionIDGlobal", uuid);
But while running it in my esb's proxy it throws null pointer exception at getCurrentMessageContext part.I have followed another approach where-in i am storing the sessionID in property mediator and tried to get its value but when i click postRequest operation after generateSessionID operation from try-it. all the property gets reset and my sessionID property gives me null value. What should i do to rectify this problem? Is there any alternate way?
You have to create servicecontext like this;
ConfigurationContext cfgCtx =(((Axis2MessageContext) synCtx).getAxis2MessageContext(). getConfigurationContext();
cfgCtx.getOperationContext().getServiceContext();
You should store in the Message context but you have stored in the service Context. please refer this to understand how you can set the properties at different scopes. Synapase (default), Axis2, Transport etc.
Please refer this blog post for complete details.
http://blog.facilelogin.com/2011/02/wso2-esb-property-mediator-different.html
Other than on the connection URL, how do I set the prefetch limit in spring config. I can't find any doc on any of the properties and the param on the Connection URL doesn't seem to work. Besides, I need to do this on the consumer level. Here is my config below.
<nms:listener-container
connection-factory="SingleConnectionFactory"
concurrency="${GraphManagerService.NMS.Consumers}"
auto-startup="false">
<nms:listener ref="MessageListenerAdapter" destination="${GraphManagerService.NMS.QueueName}" />
</nms:listener-container>
To do this on a per-consumer basis you add the option to the destination.
myQueue?consumer.prefetchSize=10
I'm trying to work out how to resume a persisted workflow that I'm self-hosting with a WorkflowServiceHost. Currently my host wires up persistence and idling behaviour like so:
// Persistence
var connStr = #"";
var behavior = new SqlWorkflowInstanceStoreBehavior(connStr);
behavior.InstanceCompletionAction = InstanceCompletionAction.DeleteNothing;
behavior.InstanceLockedExceptionAction = InstanceLockedExceptionAction.AggressiveRetry;
behavior.InstanceEncodingOption = InstanceEncodingOption.None;
host.Description.Behaviors.Add(behavior);
// Idle behaviour
var idleBehavior = new WorkflowIdleBehavior();
idleBehavior.TimeToPersist = TimeSpan.FromMinutes(2);
idleBehavior.TimeToUnload = TimeSpan.FromMinutes(2);
host.Description.Behaviors.Add(behavior);
I am storing the workflow instance GUID against a ProductID in my database inside a custom activity contained in the workflow, so I am able to easily trace a specific workflow instance to a product ID. I want to be able to somehow pass this Product ID to my ServiceHost and have it resume the correct persisted workflow for me.
Can anyone point me in the right direction on how to do this?
Many thanks in advance
Ian
You're going to want to read about Content Correlation. You'll correlate your ProductID with your Receive activities. A bookmark will be created when you reach a receive, and your workflow will be persisted. You call the receive and pass your ProductID in and because of the correlation, the WF runtime knows which instance to resume.