eCommerce Glossary: Azure Service Bus

Azure Service Bus – Working, Queues, Fundamentals, and More

What is Azure Service Bus?

Azure Service Bus offers trustworthy cloud messaging services between databases and applications, showing what is called "Messaging as a Service (MaaS) with simple hybrid integration. This article attempts to describe all that you need to know about the Service Bus in Azure. So we would take you through the following sections:

What is Azure Service Bus?
Fundamentals of Azure Service Bus
Service Bus Azure; Relays and Queues
Service Bus Azure; Topics
Advanced features of Service Bus

Microsoft Azure Service Bus can be described as an information delivery service to make communication more comfortable and reliable. If two or more parties or applications need to exchange information amongst them, they need what is called a communication facilitator. Therefore, it implies that Microsoft Azure Service Bus is an enterprise integration message broker that is fully managed and acts as a communication facilitator.

Azure transfers data between different applications and services using messages in binary format with the Service bus, which can contain JSON, XML, or plain text.

The Azure Service Bus concept is quite simple; it offers a multi-tenant cloud service system that allows multiple users to share their service and define a communication mechanism that is needed within their namespace.

Understanding Queues, Topics, & Relays

Fundamentals of Azure Service Bus

Certain fundamental concepts must be well known when talking about the Azure Service Bus. These are: Queues, Topics, ↦ Relays. Before we dive deeper into these fundamentals, here is a summary of them:

Queues
Allows for a one-way communication
Each acts as a broker that is responsible for storing messages until they are sent
Single recipient to a single message
Topics
They also help in one-way communication
It also acts as a broker but also has the characteristics of filtering messages to match particular criteria
Relays
Allows for bi-directional communication
They don't act like a broker compared to topics and relays Passes messages straight to the destination application

Service Bus Azure - Queues

Users use queues to send and receive messages. It is the main connector between the two applications. It also stores the logs until the recipient application is available to process the message. Two significant characteristics of messages in a Queue are "Order" and "Timestamp." Every message, on arrival, is ordered and timestamped.

Once the receiving application accepts the message, the message is then held in redundant storage for safekeeping. Finally, all messages use a Pull mode method in delivering messages – this means that messages are only sent when requested.

Service Bus Azure - Topics

Though a Queue sends messages using point-to-point communication, Topics also sends messages but uses a concept called the "Publisher/subscriber" scenarios. This means that topics have multiple, independent subscriptions that receive messages from a sender.

A subscriber can receive messages sent to a Topic that consists of multiple subscriptions. In this case, a subscription is referred to as an entity. Although subscriptions continue to exist, they can also be auto-deleted or expire.

Suppose you don't want all the subscriptions to receive all the messages sent to a Topic. There are "rules" and "filters" that can be used to define such actions or conditions.

Service Bus Azure - Relays

While Queues and Topics provide a one-way asynchronous communication using a broker, Relays are entirely different. Relays act as a bi-directional communication tool in which traffic flows from one destination to another; in this case, from sender to receiver. Relays do not store messages like their counterparts but send messages directly from the sender to the receiver and receiver to the sender whenever the need arises.

Expanding and Improving on Each Feature Unique to Azure Service Bus

Advanced Features of Service Bus

Certain advanced features come with a service bus that enables you to address complex issues with messaging. This section highlights some of these features of the service bus in Azure.

Message Sessions

Message sessions are used to create a FIFO (First-in, First-out) guarantee. This allows for ordered handling of infinite sequences of messages that are related.

Auto-Forwarding

This unique feature chains a subscription or a queue to another queue or topic. The only condition for this to be successful is that they must be in the same namespace. Chaining service bus entities with the auto-forwarding feature automatically remove messages from a subscription or queue and inserts them to a different queue or topic.

Dead-Letter Queue (DLQ)

A DLQ is used to hold messages that cannot be delivered to any recipient. These messages cannot be processed and thus are stored in a DLQ. The service bus supports DLQ and allows you to inspect the messages and remove them.

Scheduled Delivery

With Azure Service Bus, you can delay the processing of a message to a topic or queue and schedule it later. These are referred to as scheduled messages.

Message Deferral

Message deferral is a unique feature that allows subscription clients (subscribers) or a queue to defer receiving a message until a future time. This can be due to particular circumstances from the application. Once this is initiated, the message is kept in the queue or subscription but set aside.

There are other advanced features of Service bus in Azure, such as:

Batching or client-side batching
Transactions
Filtering and actions
Autodelete on idle
Duplicate detection; and many more

Furthermore, there are some standard security protocols that azure service bus supports, this includes:

Shared Access Signature (SAS)
AMQP 1.0
HTTP/REST protocol
Azure role-based access control (Azure RBAC)
Managed Identities for Azure resources.

In conclusion, let's enumerate the Azure service bus's benefits as a MaaS (Messaging as a Service).

Simplified cloud messaging for Enterprises
The building of durable and scalable cloud applications and solutions
Ability to implement complex messaging workflows
Secured communication across all applications despite hybrid integration
Sending ordered messages to multiple subscribers

It is crystal clear that beckoning Azure service bus cloud-based solutions for your communication will make communication convenient for your users. The Azure service bus also gives you two options to pick from; standard messaging and premium messaging. With the standard messaging, you get a variable throughput, variable latency, message size of up to 256KB, and pay-as-you-go pricing. On the other hand, the premium messaging offers high throughput, well-defined performances, workload scalability, message size of up to 1MB, and fixed pricing. Whatever your choice is, the azure service bus is the most reliable MaaS for you.