lodspeakr | create Linked Data-based applications | Messaging library

I'm not a php guy, but something like this would return only conversations involving user_id 1 and user_id 3:

Every delivered message has a set of properties. Two of these are the exchange used to route the message, and the routing key. Depending on the type of exchange you can also figure out the queue name based on this information.

https://www.rabbitmq.com/amqp-0-9-1-quickref.html

If you need to know when a message is published you can use this plugin - https://github.com/rabbitmq/rabbitmq-message-timestamp

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Found the answer, or at least a fix...

Adding @Blocking to the second step in the messaging chain seems to have decoupled the process:

The .NET client uses the ThreadPool which probably doesn't have enough threads out of the box. You need to increase the amount available:

https://github.com/rabbitmq/rabbitmq-dotnet-client/blob/main/projects/TestApplications/MassPublish/Program.cs#L21

See issues and discussion here:

https://github.com/rabbitmq/rabbitmq-dotnet-client/search?q=threadpool

_{NOTE: the RabbitMQ team monitors the rabbitmq-users mailing list and only sometimes answers questions on StackOverflow.}

Service Bus associates a message lock with the AMQP link from which the message was received. For the SDK, this means that you must settle the message with the same ServiceBusReceiver instance that you used to receive it.

In your code, you're creating a new receiver for ReceiveMessage call - so when you attempt to complete or abandon the message, you're using a link for which the message is not valid if any other call to ReceiveMessage has taken place.

Generally, you want to avoid the pattern of creating short-lived Service Bus client objects. They're intended to be long-lived and reused over the lifetime of the application. In your code, you're also implicitly abandoning the senders/receivers without closing them. This is going to orphan the AMQP link until the service force-closes it for being idle after 20 minutes.

I'd recommend pooling your senders/receivers and keeping each as a singleton for the associated queue. Each call to SendMessage or ReceiveMessage should for a given queue should use the same sender/receiver instance.

When your application closes, be sure to close or dispose the ServiceBusClient, which will ensure that all of its child senders/receivers are also cleaned up appropriately.

I'd also very strongly recommend refactoring your class to be async. The sync-over-async pattern that you're using is going to put additional pressure on the thread pool and is likely to result in thread starvation and/or deadlocks under load.

UPDATE

To add some additional context, I'd advise not wrapping Service Bus operations but, instead, have a factory that focuses on managing clients and letting callers interact directly with them.

This ensures that clients are pooled and their lifetimes are managed correctly, while also giving flexibility to callers to hold onto the sender/receiver reference and use for multiple operations rather than paying the cost to retrieve it.

As an example, the following is a simple factory class that you'd create and manage as a singleton in your application. Callers are able to request a sender/receiver for a specific queue/topic/subscription and they'll be created as needed and then pooled for reuse.

MSK VS SQS+SNS is not really 1:1 comparison. The choice depends on various use cases. Please find out some of specific difference between two

1. Scalability -> MSK has better scalability option because of inherent design of partitions that allow parallelism and ordering of message. SNS has limitation of 300 publish/Second, to achieve same performance as MSK, there need to have higher number of SNS topic for same purpose.

Example : Topic: Order Service in MSK -> one topic+ 10 Partitions SNS -> 10 topics

if client/message producer use 10 SNS topic for same purpose, then client needs to have information of all 10 SNS topic and distribution of message. In MSK, it's pretty straightforward, key needs to send in message and kafka will allocate the partition based on Key value.

1. Administration/Operation -> SNS+SQS setup is much simpler compare to MSK. Operational challenge is much more with MSK( even this is managed service). MSK needs more in depth skills to use optimally.

2. SNS +SQS VS SQS -> I believe you have multiple subscription(fanout) for same message thats why you have refer SNS +SQS. If you have One Subscription for one message, then only SQS is also sufficient.

3. Replay of message -> MSK can be use for replaying the already processed message. It will be tricky for SQS, though can be achieve by having duplicate queue so that can be use for replay.

There are two main ways of representing the sending of a movement message between two devices:

1. A movement() operation on the target device, with parameters for the velocity and direction. You would typically show the exchange in a sequence diagram, with a call arrow from the sender to the receiver. The return message could just be label as ACK.

2. A «signal» Movement: Signals correspond to event messages. In a class diagram, they are represented like a class but with the «signal» keyword: velocity and direction would be attributes of that signal. ACK would be another signal. The classes that are able to receive the signals show it as reception (looks like an operation, but again with «signal» keyword).

In both cases, you would show the interactions of your communication protocol with an almost identical sequence diagram. But signals are meant for asynchronous communication and better reflect imho the nature of the communication. It's semantic is more suitable for your needs.

If you prefer communication diagram over interaction diagrams, the signal approach would be clearer, since communication diagrams don't show return messages.

With the diagrams, your edited question is much clearer. My position about the use of signals is unchanged: signals would correspond to the information exchanged between the computer and the car. So in a class diagram, you could document the «signal»Movement as having attributes id, velocity and direction:

In your sequence diagram, you'd then send and arrow with Movement (X,100,0). Signal allows to show the high level view of the protocol exchanges, without getting lost on the practical implementation details:

The implementation details could then be shown in a separate diagram. There are certainly several classes involved on the side of the computer (one diagram, the final action being some kind of sending) and on the side of the car (another diagram: how to receive and dispatch the message, and decode its content). I do not provide examples because it would very much look like your current diagram, but the send functions would probably be implemented by a communication controller.

If you try to put the protocol and its implementation in the same diagram, as in your second diagram, it gets confusing because of the lack of separation of concerns: here you say the computer is calling a send function on the car, which is not at all what you want. The reader has then difficulty to see what's really required by the protocol, and what's the implementation details. For instance, I still don't know according to your diagram, if setVelocity is supposed to directly send something to the car, or if its a preparatory step for sending the movement message with a velocity.

Last but not least, keep in mind that the sequence diagram represents just a specific scenario. If you want to formally define a protocol in UML, you'd need to create as well a protocol state machine that tells the valid succession of messages. When you use signals, you can use their name directly as state transition trigger/event.

According to the official docs

• It is possible to grab message starting from a certain time: in the last 1.5 seconds.

DeliverByStartTime
When first consuming messages, start with messages on or after this time. The consumer is required to specify OptStartTime, the time in the stream to start at. It will receive the closest available message on or after that time.

• The other requirement, the last 15 messages, I think it's not possible

I don't believe WildFly supports a suffix or prefix for the JDBC table names so you'll need to manually set the table names for the journal configuration. Here's the list of attributes:

• messages-table
• bindings-table
• jms-bindings-table
• large-messages-table
• node-manager-store-table
• page-store-table

These will need to be unique for each server.