Azure Queue Storage

Azure Queue Storage is a service that stores large numbers of relatively coarse-grained messages that are in various states of processing. Use Queue Storage to decouple application components that are asynchronously processing tasks.

Introduction

Queue Storage is a REST-accessible, fully managed service on Azure that provides reliable, queue-based messaging for large volumes of messages. It enables you to build distributed applications and services. Messages can be up to 64 KB in size, and a queue can contain any number of messages. The total capacity of a storage account is limited by the size of the storage account.

Core Concepts

Understanding these core concepts is crucial for working effectively with Azure Queue Storage:

• Queue: A collection of messages. Each queue must have a name. Queue names must be DNS-compliant names, using lowercase letters, numbers, hyphens, and periods.
• Message: A unit of data passed between application components. Messages are typically strings and are base64 encoded when stored.
• Message ID: A unique identifier for a message returned by the service.
• Pop Receipt: A string that identifies a specific instance of a message in a queue. It is required to delete or update a message.
• Visibility Timeout: The duration for which a message is invisible to other consumers after being dequeued.

Getting Started

To get started with Azure Queue Storage, you'll need an Azure Storage account. You can create one via the Azure portal, Azure CLI, or Azure PowerShell.

1. Create a Storage Account

Using Azure CLI:

az storage account create \
    --name mystorageaccount \
    --resource-group myresourcegroup \
    --location eastus \
    --sku Standard_LRS
            

2. Access Queue Storage

You can interact with Queue Storage using:

• REST API: Directly make HTTP requests to the Queue Storage endpoint.
• Azure SDKs: Use client libraries available for various programming languages.
• Azure CLI: Command-line interface for managing Azure resources.
• Azure Portal: A web-based interface for managing your storage account.

API Operations

Key operations for Queue Storage include:

• Put Message: Adds a new message to the queue.
• Get Messages: Retrieves one or more messages from the queue.
• Delete Message: Deletes a specific message from the queue.
• Peek Messages: Retrieves one or more messages from the queue without making them invisible.
• Clear Messages: Deletes all messages from a queue.
• Get Queue Metadata: Retrieves metadata about a queue.

Example: Adding a Message (REST API)

This example shows how to add a message using a simple `PUT` request.

PUT http://myaccount.queue.core.windows.net/myqueue/messages?pop=true&numofmesg=1&visibilitytimeout=30 HTTP/1.1
Content-Length: 165
x-ms-version: 2020-08-04
Date: Mon, 23 Nov 2020 22:32:01 GMT
Authorization: SharedKey mystorageaccount:kP6fQc5u5mF0vT6xW9t7hP/fW0/yE6q9B2zD1iG7eXg=
Content-Type: application/xml

<QueueMessage><MessageText>This is my message</MessageText></QueueMessage>
            

Client Libraries

Azure provides client libraries to simplify interaction with Queue Storage. Here's a quick example using the Node.js SDK:

const { QueueServiceClient } = require("@azure/storage-queue");

async function sendMessage() {
    const connectionString = "YOUR_AZURE_STORAGE_CONNECTION_STRING";
    const queueServiceClient = QueueServiceClient.fromConnectionString(connectionString);

    const queueName = "my-test-queue";
    const queueClient = queueServiceClient.getQueueClient(queueName);

    await queueClient.createMessage("Hello, Azure Queue Storage!");
    console.log(`Message sent to ${queueName}`);
}

sendMessage().catch((error) => {
    console.error("Error sending message:", error);
});
            

Monitoring and Management

Monitor the performance and health of your Queue Storage with Azure Monitor. Key metrics include queue length, message count, and transaction success rates.

You can also use Azure Storage Explorer for a graphical interface to manage your queues and messages.

Pricing

Queue Storage pricing is based on:

• Data stored
• Number of operations performed
• Data egress

Refer to the Azure Queue Storage pricing page for detailed information.

Frequently Asked Questions

What is the maximum message size?

64 KB.

What is the maximum queue size?

Limited by the capacity of your storage account.

Can I use Queue Storage for real-time communication?

No, Queue Storage is designed for asynchronous messaging. For real-time communication, consider Azure SignalR Service.