It is possible to configure an alert on azure sb that gets triggered when dlc reaches a certain threshold or a queue reaches it's maximum.
However it seems these alerts are triggered on namespace level meaning the linked action (like email) is not mentioning the exact queue only the namespace name.
This makes it difficult to find out what queue is causing the problem if a namespace contains multiple queues.
So my question: is it possible to get more information about the queue/topic itself in the alert notification (mail) ?
What are best practices to deal with this kind of requirement ?
Individual entities (queue/topic) will have their individual dead letter queue. The dead letter queue space is added to the total space of the entity.
Your monitor alert will have the Dimensions details about the entity as below.
For more details on the alert refer to this document
Service Bus Message Metrices: https://learn.microsoft.com/en-us/azure/service-bus-messaging/monitor-service-bus-reference#message-metrics
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I'm trying to find a solution for receiving large messages on Azure Service Bus. The essential pattern I was thinking is to publish a large messages in parts -- along with a correlation id, a page, and an "of".
So if I have a four-part message, they would all have the same correlation id, each would have an "of" of 4, and the page would be 0 - 3. The set would be published as a batch.
The listener could listen for only messages with a page of 0, and then pull the remaining messages according to the transaction id.
Publishing these messages is easy enough. ServiceBusMessage has a CorrelationId field, and a dictionary field called ApplicationProperties that I can add my custom "page" and "of" fields to. I can assemble them into a ServiceBusMessageBatch before publishing.
What I'm not sure about is how to receive the messages. I'm using Function Apps, so it's easy to setup a listener.
[FunctionName("GeneralLogger")]
public static void Run([ServiceBusTrigger("queueName", Connection = "AzureWebJobsServiceBus")] string myQueueItem, ApplicationProperties ap, ILogger log)
{ /// process message }
But I don't see how to filter here. Also, I can pull messages by adding a handler to the message processor, described here: https://learn.microsoft.com/en-us/azure/service-bus-messaging/service-bus-dotnet-get-started-with-queues But likewise I don't see how to filter.
The only Azure Service Bus filtering I see how to do is between a topic and subscription. There is a lot of capability there, but nothing dynamically I can set during runtime.
I feel like I'm either trying to miss-use something or re-inventing the wheel. Is anyone else doing something like this with Azure Service Bus?
I'm trying to find a solution for receiving large messages on Azure Service Bus.
A solution is already there. It's Azure Service Bus premium tier. Capable of sending messages up to 100MB in size. It comes with a price. Assuming you're looking to spit up the file either because the premium is much to pay for or because messages could be larger than 100MB, the claim-check pattern is the way to go. There's just one issue when the claim-check pattern is used over the premium tier - you cannot have a deterministic clean-up when a message is an event, and there are multiple receivers. You'd need to come up with some policy to clean up those blobs, given that those are large blobs and will quickly add to the storage consumption over time, depending on the number of messages flowing through the system. With the premium tier, the problem of clean-up doesn't exist. Nor do you have to provide a storage account. Therefore, if your large messages will not exceed 100MB, it could be a more suitable solution for your production environment.
It isn't possible to apply filters on a queue; they only operate on topics/subscriptions.
Generally, the Claim Check pattern is recommended when you're looking to send a payload too large for a single message. In a nutshell, you would write your payload to some form of durable storage and then your Service Bus message would provide the location for consumers.
An example implementation using the Azure.Messaging.ServiceBus package can be found in this sample.
In Azure, we have two separate messaging technologies and it's not very well documented when to use what? While EventGrid is really cool, I did not come across when to use EventGrid(scenarios) vs the Storage/ServiceBus queue? Can someone help?
E.g. if I have the following scenario :
A status of a flag changes and based on that, I want to trigger an algorithm that would do recalculations, few inserts/updates etc. in the database.
For implementing this - I can either use EventGrid or Storage Queue. How do we figure what to use in such scenario? I was looking for some kind of guidance.
Basically, Azure Event Grid handles events and Azure ServiceBus handles messages.A message is raw data produced by a service to be consumed or stored. Events are also messages (lightweigth), but they don’t generally convey a publisher intent, other than to inform.
1) If the purpose is to just to store the information ServiceBus can be used.
2) If the information received is used to trigger another service Azure Event Grid can be used.
Find more info here
https://learn.microsoft.com/en-us/azure/event-grid/compare-messaging-services
https://azure.microsoft.com/en-us/blog/events-data-points-and-messages-choosing-the-right-azure-messaging-service-for-your-data/
Events are like notifications from a service to inform the world that something happened in the domain of the publisher (similar to an email notification). There is no expectations from the publisher to have any actions taken. A message is a command you send to a specific receiver with the expectation of the message to be processed (like an asynchronous post request).
Events will work in pub/sub pattern and multiple subscribers could be configured to the events. The service that needs to react to an event will get notified by the event grid when an event occurs (http call from event grid to the receiver). The event will remain in the event grid until deletion (cleanup) and there is no garantie of keeping the original order (no FIFO).
In the other hand, messages will be added to a queue and will be deleted once the “message processor” is done with it. The messages in the queue will keep the original order (FIFO). The message processor has to pull messages from the queue.
In your scenario, you could use a combination of both. Service A sends an event “StatusChanged”, then you can configure a subscription to that event and send a message to a queue, then have your logic to process that message. This will end up with a fully async communication pattern. This is ideal to support scenarios where you processor is down or too busy. The incoming messages will simply get accumulated in the queue and eventually being processed once the service is back up and running. And without affecting the original service that sent the “StatusChanged” event..
First service adds messages to queue if user does not exist in DB, second service gets message from queue and create user. Possible situation, when first service adds 2 messages for create users before second gets it. How to resolve it? As I understand, no way to review queue...
I use Azure Storage queues
Azure Queue message doesn't support peek-lock to be processed. Once it is read, it becomes invisible. You need to look into Azure Service Bus as it allows you to control message one by one and in order if required.
I was under the impression that this was not available with storage queue but after investigating I can't find proof of this.
MSDN articles say At-Least-Once but the most information I can find is that the first consumer gets the message and sets the message to invisible.
Then when it becomes visible again it could be picked up again.
However I could set invisible to a large TimeSpan and I could check Dequeue count to limit it to At-Most-Once delivery.
This is using the assumption that competing consumers can't grab the same message at the same time which I can't verify.
If your question is whether Storage Queues offer at most once delivery, the answer is no. If you need at most once, use Service Bus queues. See the Foundational Capabilities section here: https://learn.microsoft.com/en-us/azure/service-bus-messaging/service-bus-azure-and-service-bus-queues-compared-contrasted
Does the Azure Service Bus and its on-premise version, Service Bus for Windows Server, replicate a message for every subscriber?
For example, let's say that there is a single topic with five subscribers, then is that message stored in the service bus' database five times - once for each subscriber - or is that message only stored once with business logic to determine which subscribers have read the message?
It would be nice if there is an official site and/or documentation to provide as a reference.
The behavior the Azure Service Bus seems to be that it is keeping a copy per subscriber. I tested this by creating a topic with two subscriptions. I sent in a single message and I see that the size of the Topic in Bytes is 464 (using topic.SizeInBytes). When I receive one message of a subscription the size the drops in half to 232. I tested it with three subscriptions and same behavior occurred: 696 bytes.
Even if they aren't keeping a copy of the message per subscription they are counting the size of the message times the number of subscriptions against the maximum size of the topic, which may be what you were trying to determine.
I agree it would be nice if they documented the behavior, especially for Service Bus for Windows Server since that could affect planning for the amount of storage you need to set aside. As for the Azure Service Bus side, I'm not sure the implementation behind the scenes matters as much as knowing how it factors towards the max size of the topic.
A subscription to a topic resembles a virtual queue that receives
copies of the messages that were sent to the topic. You can optionally
register filter rules for a topic on a per-subscription basis, which
allows you to filter/restrict which messages to a topic are received
by which topic subscriptions.
I think it copies messages. If it does not copy, it should check always, did all subscribers get the messages ? Additionally, if there is filter, it should check just these subscribers to delete message. I think, copying and applying simple consume implemation cost is less than without copying cost.
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