Skip to main content

Windows Azure Service Bus Topic - Detect messages that don't have subscribers

Windows Azure Service Bus Topic is a great service that provide as the ability to distribute a message to more than one subscriber. When we publish a message to Service Bus Topic we don’t need to know how many subscribers are. Each subscriber can register to a topic and receive the messages (each subscriber can define custom rules – to filter what kind of message he wants to receive).
But how can we check if a message will be received by at least one subscriber. When we publish a message we don’t know who will receive the message, because of this we need a way to know what messages were not received by anyone. In this current implementation of Service Bus Topic, when a message is send to the Service Bus Topic and the current messages is not accepted by any subscriber, the message is not persisted in the Topic. Because of this the message will be lost and we will not be notifies about this action.
Service Bus Topic give us the ability to be notifies when we send a message to the Service Bus Topic and will not be received by any subscriber. When we create the topic, we need to set the “EnableFilteringMessagesBeforePublishing” to TRUE. In this moment when we will send a message to the topic, Windows Azure will check if there are subscribers for these messages. When there are subscribers everything will go as normal, but when there will be 0 subscribers for our message, a NoMatchingSubscriptionException will be throw. This exception will notify us that there are not subscribers for our client and we will be able to take any kind of action.
To create a topic with this setup we need to do the following:
NamespaceManager namespaceManager = NamespaceManager.CreateFromConnectionString([connectionString]);
namespaceManager.CreateTopic(
                    new TopicDescription([topicName]) 
                    { 
                       EnableFilteringMessagesBeforePublishing = true 
                    });
When we send the message we will need to cache “NoMatchingSubscriptionException” exception and do our custom action.
We saw the mechanism that Windows Azure offer to us the detect messages that don’t have at least one subscriber. If we don’t need to know and detect them we can set this flag to FALSE. This is a great mechanism that is very easy to use.

Comments

  1. "Service Bus has one feature that is used specifically for development which should never be used in production configurations: TopicDescription.EnableFilteringMessagesBeforePublishing."

    https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-performance-improvements#development--testing-features

    ReplyDelete

Post a Comment

Popular posts from this blog

How to audit an Azure Cosmos DB

In this post, we will talk about how we can audit an Azure Cosmos DB database. Before jumping into the problem let us define the business requirement: As an Administrator I want to be able to audit all changes that were done to specific collection inside my Azure Cosmos DB. The requirement is simple, but can be a little tricky to implement fully. First of all when you are using Azure Cosmos DB or any other storage solution there are 99% odds that you’ll have more than one system that writes data to it. This means that you have or not have control on the systems that are doing any create/update/delete operations. Solution 1: Diagnostic Logs Cosmos DB allows us activate diagnostics logs and stream the output a storage account for achieving to other systems like Event Hub or Log Analytics. This would allow us to have information related to who, when, what, response code and how the access operation to our Cosmos DB was done. Beside this there is a field that specifies what was th...

Cloud Myths: Cloud is Cheaper (Pill 1 of 5 / Cloud Pills)

Cloud Myths: Cloud is Cheaper (Pill 1 of 5 / Cloud Pills) The idea that moving to the cloud reduces the costs is a common misconception. The cloud infrastructure provides flexibility, scalability, and better CAPEX, but it does not guarantee lower costs without proper optimisation and management of the cloud services and infrastructure. Idle and unused resources, overprovisioning, oversize databases, and unnecessary data transfer can increase running costs. The regional pricing mode, multi-cloud complexity, and cost variety add extra complexity to the cost function. Cloud adoption without a cost governance strategy can result in unexpected expenses. Improper usage, combined with a pay-as-you-go model, can result in a nightmare for business stakeholders who cannot track and manage the monthly costs. Cloud-native services such as AI services, managed databases, and analytics platforms are powerful, provide out-of-the-shelve capabilities, and increase business agility and innovation. H...

Cloud Myths: Migrating to the cloud is quick and easy (Pill 2 of 5 / Cloud Pills)

The idea that migration to the cloud is simple, straightforward and rapid is a wrong assumption. It’s a common misconception of business stakeholders that generates delays, budget overruns and technical dept. A migration requires laborious planning, technical expertise and a rigorous process.  Migrations, especially cloud migrations, are not one-size-fits-all journeys. One of the most critical steps is under evaluation, under budget and under consideration. The evaluation phase, where existing infrastructure, applications, database, network and the end-to-end estate are evaluated and mapped to a cloud strategy, is crucial to ensure the success of cloud migration. Additional factors such as security, compliance, and system dependencies increase the complexity of cloud migration.  A misconception regarding lift-and-shits is that they are fast and cheap. Moving applications to the cloud without changes does not provide the capability to optimise costs and performance, leading to ...