I wish to run an experiment in which the publisher loses connection with the broker and then enqueues messages in its own queue and then when it regains connectivity it sends all its queued messages to the broker. How can I I do this since if I call close connection, I can no longer send(raises an exception). A trick that I can think of is to use a network of two brokers and simulate the above by breaking the connection between the two brokers. Is there an API call that I can use to do the above?
This is very much like facebook messenger or whatsapp acting as a publisher and enqueuing our to-send messages if we are offline and sending them once we are connected.
There is plenty of solutions you could use to break the connection in order to test, here is a non-comprehensive list :
Make a script that can set/unset a firewall rule on your environement blocking the connection port
If you are working with VMs, you can suspend/resume the one running Activemq, you can even automate it with tools like vagrant (vagrant suspend, then vagrant up)
Tweak the connection manualy accessing the activemq jmx
Develop an activemq plugin able to trash connections on demand (or maybe there is one ?)
Now in order to have the behavior you wish to obtain there is two options :
1) Make sure your connection is failover so it can be reestablished, and store your message on disk before sending them with your producer.
2)Produce to a local broker embbeded in your app, and connect this one to the remote broker.
Related
I am facing a weird problem with connecting Rabbitmq from UI. I use 'xhr-polling' only due to some reason to connect rabbitmq queue from UI and it works fine for quite sometime when user lands on page but it disconnects with rabbitmq at some point without any error.
I have put in some logic to reconnect, once it is disconnected and as per the log it seems it connects but when I look at the RabbitMQ there is no client connected to it. However browser console (connected to server RabbitMQ/3.6.10) and keeps sending calling xhr_send?t=[random-key] and xhr?=[random-key] gets response 204 or 200 (As per developer tool).
When I refresh the whole page, it connects back again fine and see rabbitmq client queue as well something like (connected to server RabbitMQ/3.6.10).
Technology stacks are : Sockjs + Stompjs + RabbitMQ with Stomp plugin
So in summary reconnect logic shows it is connected but as per rabbitmq there is no subscribed client. Normally I see something like this stomp-subscription-rIUXo4Yvmilga2w3g5Lu6g as queue name when connected.
I am new to RabbitMQ and I am working on an application that will receive information from many devices and route all messages into a couple of queues depending on the MQTT topic. I was able to get all of this working easily, but now I am looking into how to push a message to a queue when a client connects or disconnects from RabbitMQ in order to update the current status of the client in my database. Is there a way to do this?
Event Exchange Plugin
Client connection, channels, queues, consumers, and other parts of the system naturally generate events. For example, when a connection is accepted, authenticated and access to the target virtual host is authorised, it will emit an event of type connection_created. When a connection is closed or fails for any reason, a connection_closed event is deleted.
Unfortunately the rabbitmq_event_exchange is created after importing bindings from definition.json. Which means that the amq.rabbitmq.event cannot be bound to a queue via the configuration and must be bound after the start.
I have a webpage connecting to a rabbit mq broker using javascript/websockets that are exposed by a spring app deployed in tomcat. Messages are produced 1 per second by an external application and are rendered on the webpage. The javascript subscription is durable.
The issue I'm experiencing is that when the network connection is broken on the javascript client for a period of time (say 60 seconds), the first ~24 seconds of messages are missing. I've looked through the logs of the app deployed in tomcat and the missing messages seem to be up until the following log statement:
org.springframework.messaging.simp.stomp.StompBrokerRelayMessageHandler - DEBUG - TCP connection to broker closed in session 14
I think this is the point at which the endpoint realises the javascript client is disconnected and decides to close the connection to the broker resulting in future messages queueing up.
My question is how can I ensure that the messages between the time the network is severed and the time the endpoint realises the client is disconnected are not lost? Should the endpoint put the messages back on the queue somehow? Maybe there's a way to make it transactional?
Thanks in advance.
The RabbitMQ team monitors this mailing list and only sometimes answers questions on StackOverflow.
Your Tomcat application should not acknowledge messages from RabbitMQ until it confirms that your Javascript client has received them. This way, any messages that aren't ack-ed by the JS client won't be ack-ed by Tomcat, and RabbitMQ will re-deliver them.
I don't know how your JS app and Tomcat interact, but you may have to implement your own ack process there.
I'm new to RabbitMQ / EasyNetQ and am trying to better understand a behaviour I am observing. We've seen that when our server running RabbitMQ is busy all EasyNetQ connections are dropped.
This is the exception simultaneously generated on all clients:
System.Exception: Failed to connect to Broker: 'XXXXXX.domain.com',
Port: 5672 VHost: 'XXXX'. ExceptionMessage: 'None of the specified
endpoints were reachable'
EasyNetQ automatically reconnects when the server is no longer busy, but I wonder if it is typical for RabbitMQ/EasyNetQ to drop connections when the machine is busy? (Or if I should be investigating performance issues with my server.)
(PS: By busy, I simply mean updating a large project from source control, relaunching a large ASP.NET application after redeploying it or running a CPU-intensive calculation on large amounts of data. ).
There are limits to the number of connections a RabbitMQ broker will accept. Is it possible that you are rapidly opening a connection, doing some work, then closing it, much as you would with a database connection? If so, that's not how you should interact with the broker. See the EasyNetQ documentation on connections:
https://github.com/mikehadlow/EasyNetQ/wiki/Connecting-to-RabbitMQ
I have a two activeMQ(5.6.0) brokers. They use a shared kaha database so only one can be 'running' at once.
I have a (asp.net) webservice that puts a message on a queue, locally if I start and stop the brokers the webservice fails over correctly
when I test with the brokers on seperate machines it sometimes works but often I get "socketException: Connection reset" errors and the message is lost.
The connection string I am using is below. Note that I am aware NMS does not understand the priority backup command but I have left it there for the future.
failover:(tcp://MACHINE1:61616,tcp://MACHINE2:62616)?transport.initialReconnectDelay=1000&transport.timeout=10000&randomize=false&priorityBackup=true
How can I make my fail over between brokers fool proof?
The shared Kaha database was on a simple share. Currently activeMQ (or windows) cannot reliably get or release the lock in this configuration. The shared database must sit on a 'real' SAN so that both instances of the queue software see the database as being on a local filestore not a network location.
See this page for more info http://activemq.apache.org/shared-file-system-master-slave.html