I'm able to queue messages as strings on my queue via the RabbitMQ Manager. My problem is that my app will be using Protocol Buffers and I can't figure out how to queue the raw bytes of a protocol buffer. I'm able to en-queue and de-queue protocol buffer messages through my app but I want to be able to queue messages through the RabbitMQ Manager and de-queue via my app.
I found this tool called Protocol Buffers Workbench (http://blog.functionalfun.net/2010/10/getting-started-with-protocol-buffers.html) which will convert my message to raw bytes. I can't however figure out how to take the raw bytes and en-queue them through the RabbitMQ Manager.
Is there an easy way to do this?
I couldn't find an easy way to do this so I wrote my own program to do it for me:
https://github.com/thereallisa/proto_enqueue
Related
We are currently using RabbitMQ Dynamic Shovels to forward messages to Azure Event Hub. Recently we setup a new Queue to be forwarded to Event Hub. Some messages in this Queue have a size of over 1MB which is the limit for messages on Event Hub. Because of this limit the messages bounce back and are sent again a few times each second. This creates a lot of network traffic which can be an issue.
Is there any way to send messages that bounce back to a DLX (dead letter exchange) or to a different queue? We have looked for some Dynamic Shovel options but could not find any that would be of any use.
Thank you Jesse Squire. Posting your suggestion as an answer to help other community members.
Generally, for cases when your payload is (or may be) larger than the allowable size, we recommend considering the claim check pattern where you store your payload in some other durable store (such as Blob storage) and then publish the event with a body that points to that resource.
You can refer to Dead-lettering dead-lettered messages in RabbitMQ.
You can also open an issue on GitHub: rabbitmq-server
I want to transfer an image from a client to the server using RabbitMQ. However, from whatever I read, I understood that RabbitMQ can only transfer a stream of text. So how to transfer an image?
The amqp body is a buffer, you can send what you want.
In general, if you want to send a file, you have to read it and send the buffers.
You should send the file using more publish and not just one, then recreate the file on the consumer side.
You should avoid sending big buffer.
I am a newbie to RabbitMQ, hence need guidance on a basic question:
Does RabbitMQ send messages to consumer as they arrive?
OR
Does RabbitMQ send messages to consumer as they become available?
At message consumption endpoint, I am using com.rabbitmq.client.QueueingConsumer.
Looking at the sprint client source code, I could figure out that
QueueingConsumer keeps listening on socket for any messages the broker sends to it
Any message that is received is parsed and stored as Delivery in a LinkedBlockingQueue encapsulated inside the QueueingConsumer.
This implies that even if the message processing endpoint is busy, messages will be pushed to QueueingConsumer
Is this understanding right?
TLDR: you poll messages from RabbitMQ till the prefetch count is exceeded in which case you will block and only receive heart beat frames till the fetch messages are ACKed. So you can poll but you will only get new messages if the number of non-acked messages is less than the prefetch count. New messages are put on the QueueingConsumer and in theory you should never really have much more than the prefetch count in that QueueingConsumer internal queue.
Details:
Low level wise for (I'm probably going to get some of this wrong) RabbitMQ itself doesn't actually push messages. The client has to continuously read the connections for Frames based on the AMQP protocol. Its hard to classify this as push or pull but just know the client has to continuously read the connection and because the Java client is sadly BIO it is a blocking/polling operation. The blocking/polling is based on the AMQP heartbeat frames and regular frames and socket timeout configuration.
What happens in the Java RabbitMQ client is that there is thread for each channel (or maybe its connection) and that thread loops gathering frames from RabbitMQ which eventually become commands that are put in a blocking queue (I believe its like a SynchronousQueue aka handoff queue but Rabbit has its own special one).
The QueueingConsumer is a higher level API and will pull commands off of that handoff queue mentioned early because if commands are left on the handoff queue it will block the channel frame gathering loop. This is can be bad because timeout the connection. Also the QueueingConsumer allows work to be done on a separate thread instead of being in the same thread as the looping frame thread mentioned earlier.
Now if you look at most Consumer implementations you will probably notice that they are almost always unbounded blocking queues. I'm not entirely sure why the bounding of these queues can't be a multiplier of the prefetch but if they are less than the prefetch it will certainly cause problems with the connection timing out.
I think best answer is product's own answer. As RMQ has both push + pull mechanism defined as part of the protocol. Have a look : https://www.rabbitmq.com/tutorials/amqp-concepts.html
Rabbitmq mainly uses Push mechanism. Poll will consume bandwidth of the server. Poll also has time gaps between each poll. It will not able to achieve low latency. Rabbitmq will push the message to client once there are consumers available for the queue. So the connection is long running. ReadFrame in rabbitmq is basically waiting for incoming frames
I am developing an app. and I am using activemq. Is there any way to do that one producer always send messages to one broker but on the opposite side there 3 consumers.Each consumer listens broker and can take any of message from queue.Is this possible?
I am using activemq for writing my app. logs to db.As u know writing logs to db is time taking process.That's why consumer is more and more slow than producer.For ex. I send 100.000 message(huge objects).Producer finishes sending messages in 20 mins.But When the producer finished, consumer has finished 4.000 message processing yet.
Yes, what you are describing is possible. In fact, you can have any number of consumers listening on a single queue. The messages are dispatched in a round-robin fashion between consumers.
What you should be aware of is that ActiveMQ performs much better sending small messages than large ones. If you need to send very large payloads (e.g. 100mb), you are far better off saving the message to a location that is accessible by both the producer and consumers (e.g. a network file system), and sending the location of the message instead. The consumer can then use that to read the message manually. This way you get a relatively small amount of traffic through the message broker.
How long will messages published to a Redis channel stay there ? Also, is there is a way to configure the max. lifetime of a message per channel ? Is there a way to control the channel size or does the channel continues to store messages as long as the Redis server has free memory ?
Redis pub/sub doesn't persist published messages. What you are looking for seems more like a message queue which can be implemented using a combination of pub/sub and lists. For more information see pattern sections in RPOPLPUSH command.