Send messages to and receive messages from Azure Service Bus queues (Python)

In this tutorial, you complete the following steps:

  1. Create a Service Bus namespace, using the Azure portal.
  2. Create a Service Bus queue, using the Azure portal.
  3. Write Python code to use the azure-servicebus package to:
    1. Send a set of messages to the queue.
    2. Receive those messages from the queue.

Note

This quick start provides step-by-step instructions for a simple scenario of sending messages to a Service Bus queue and receiving them. You can find pre-built JavaScript and TypeScript samples for Azure Service Bus in the Azure SDK for Python repository on GitHub.

Prerequisites

If you're new to the service, see Service Bus overview before you do this quickstart.

To use this quickstart with your own Azure account:

  • Install Azure CLI, which provides the passwordless authentication to your developer machine.
  • Set Azure Environment as Azure operated by 21Vianet with az cloud set -n AzureChinaCloud.
  • Sign in with your Azure account at the terminal or command prompt with az login.
  • Use the same account when you add the appropriate data role to your resource.
  • Run the code in the same terminal or command prompt.
  • Note the queue name for your Service Bus namespace. You'll need that in the code.

Note

This tutorial works with samples that you can copy and run using Python. For instructions on how to create a Python application, see Create and deploy a Python application to an Azure Website. For more information about installing packages used in this tutorial, see the Python Installation Guide.

Create a namespace in the Azure portal

To begin using Service Bus messaging entities in Azure, you must first create a namespace with a name that is unique across Azure. A namespace provides a scoping container for Service Bus resources within your application.

To create a namespace:

  1. Sign in to the Azure portal.

  2. In the left navigation pane of the portal, select All services, select Integration from the list of categories, hover the mouse over Service Bus, and then select Create on the Service Bus tile.

    Image showing selection of Create a resource, Integration, and then Service Bus in the menu.

  3. In the Basics tag of the Create namespace page, follow these steps:

    1. For Subscription, choose an Azure subscription in which to create the namespace.

    2. For Resource group, choose an existing resource group in which the namespace will live, or create a new one.

    3. Enter a name for the namespace. The namespace name should adhere to the following naming conventions:

      • The name must be unique across Azure. The system immediately checks to see if the name is available.
      • The name length is at least 6 and at most 50 characters.
      • The name can contain only letters, numbers, hyphens "-".
      • The name must start with a letter and end with a letter or number.
      • The name doesn't end with "-sb" or "-mgmt".
    4. For Location, choose the region in which your namespace should be hosted.

    5. For Pricing tier, select the pricing tier (Basic, Standard, or Premium) for the namespace. For this quickstart, select Standard.

      Important

      If you want to use topics and subscriptions, choose either Standard or Premium. Topics/subscriptions aren't supported in the Basic pricing tier.

      If you selected the Premium pricing tier, specify the number of messaging units. The premium tier provides resource isolation at the CPU and memory level so that each workload runs in isolation. This resource container is called a messaging unit. A premium namespace has at least one messaging unit. You can select 1, 2, 4, 8 or 16 messaging units for each Service Bus Premium namespace. For more information, see Service Bus Premium Messaging.

    6. Select Review + create at the bottom of the page.

      Image showing the Create a namespace page

    7. On the Review + create page, review settings, and select Create.

  4. Once the deployment of the resource is successful, select Go to resource on the deployment page.

    Image showing the deployment succeeded page with the Go to resource link.

  5. You see the home page for your service bus namespace.

    Image showing the home page of the Service Bus namespace created.

Create a queue in the Azure portal

  1. On the Service Bus Namespace page, select Queues in the left navigational menu.

  2. On the Queues page, select + Queue on the toolbar.

  3. Enter a name for the queue, and leave the other values with their defaults.

  4. Now, select Create.

    Image showing creation of a queue in the portal

Authenticate the app to Azure

This quick start shows you two ways of connecting to Azure Service Bus: passwordless and connection string. The first option shows you how to use your security principal in Azure Active Directory and role-based access control (RBAC) to connect to a Service Bus namespace. You don't need to worry about having hard-coded connection string in your code or in a configuration file or in a secure storage like Azure Key Vault. The second option shows you how to use a connection string to connect to a Service Bus namespace. If you are new to Azure, you may find the connection string option easier to follow. We recommend using the passwordless option in real-world applications and production environments. For more information, see Authentication and authorization. You can also read more about passwordless authentication on the overview page.

Assign roles to your Azure AD user

When developing locally, make sure that the user account that connects to Azure Service Bus has the correct permissions. You'll need the Azure Service Bus Data Owner role in order to send and receive messages. To assign yourself this role, you'll need the User Access Administrator role, or another role that includes the Microsoft.Authorization/roleAssignments/write action. You can assign Azure RBAC roles to a user using the Azure portal, Azure CLI, or Azure PowerShell. Learn more about the available scopes for role assignments on the scope overview page.

The following example assigns the Azure Service Bus Data Owner role to your user account, which provides full access to Azure Service Bus resources. In a real scenario, follow the Principle of Least Privilege to give users only the minimum permissions needed for a more secure production environment.

Azure built-in roles for Azure Service Bus

For Azure Service Bus, the management of namespaces and all related resources through the Azure portal and the Azure resource management API is already protected using the Azure RBAC model. Azure provides the below Azure built-in roles for authorizing access to a Service Bus namespace:

  • Azure Service Bus Data Owner: Enables data access to Service Bus namespace and its entities (queues, topics, subscriptions, and filters). A member of this role can send and receive messages from queues or topics/subscriptions.
  • Azure Service Bus Data Sender: Use this role to give the send access to Service Bus namespace and its entities.
  • Azure Service Bus Data Receiver: Use this role to give the receive access to Service Bus namespace and its entities.

If you want to create a custom role, see Rights required for Service Bus operations.

Add Azure AD user to Azure Service Bus Owner role

Add your Azure AD user name to the Azure Service Bus Data Owner role at the Service Bus namespace level. It will allow an app running in the context of your user account to send messages to a queue or a topic, and receive messages from a queue or a topic's subscription.

Important

In most cases, it will take a minute or two for the role assignment to propagate in Azure. In rare cases, it may take up to eight minutes. If you receive authentication errors when you first run your code, wait a few moments and try again.

  1. If you don't have the Service Bus Namespace page open in the Azure portal, locate your Service Bus namespace using the main search bar or left navigation.

  2. On the overview page, select Access control (IAM) from the left-hand menu.

  3. On the Access control (IAM) page, select the Role assignments tab.

  4. Select + Add from the top menu and then Add role assignment from the resulting drop-down menu.

    A screenshot showing how to assign a role.

  5. Use the search box to filter the results to the desired role. For this example, search for Azure Service Bus Data Owner and select the matching result. Then choose Next.

  6. Under Assign access to, select User, group, or service principal, and then choose + Select members.

  7. In the dialog, search for your Azure AD username (usually your user@domain email address) and then choose Select at the bottom of the dialog.

  8. Select Review + assign to go to the final page, and then Review + assign again to complete the process.

Use pip to install packages

  1. To install the required Python packages for this Service Bus tutorial, open a command prompt that has Python in its path, change the directory to the folder where you want to have your samples.

  2. Install the following packages:

    pip install azure-servicebus
    pip install azure-identity
    pip install aiohttp
    

Send messages to a queue

The following sample code shows you how to send a message to a queue. Open your favorite editor, such as Visual Studio Code, create a file send.py, and add the following code into it.

  1. Add import statements.

    import asyncio
    from azure.servicebus.aio import ServiceBusClient
    from azure.servicebus import ServiceBusMessage
    from azure.identity.aio import DefaultAzureCredential
    
  2. Add constants and define a credential.

    FULLY_QUALIFIED_NAMESPACE = "FULLY_QUALIFIED_NAMESPACE"
    QUEUE_NAME = "QUEUE_NAME"
    
    credential = DefaultAzureCredential()
    

    Important

    • Replace FULLY_QUALIFIED_NAMESPACE with the fully qualified namespace for your Service Bus namespace.
    • Replace QUEUE_NAME with the name of the queue.
  3. Add a method to send a single message.

    async def send_single_message(sender):
        # Create a Service Bus message and send it to the queue
        message = ServiceBusMessage("Single Message")
        await sender.send_messages(message)
        print("Sent a single message")
    

    The sender is an object that acts as a client for the queue you created. You'll create it later and send as an argument to this function.

  4. Add a method to send a list of messages.

    async def send_a_list_of_messages(sender):
        # Create a list of messages and send it to the queue
        messages = [ServiceBusMessage("Message in list") for _ in range(5)]
        await sender.send_messages(messages)
        print("Sent a list of 5 messages")
    
  5. Add a method to send a batch of messages.

    async def send_batch_message(sender):
        # Create a batch of messages
        async with sender:
            batch_message = await sender.create_message_batch()
            for _ in range(10):
                try:
                    # Add a message to the batch
                    batch_message.add_message(ServiceBusMessage("Message inside a ServiceBusMessageBatch"))
                except ValueError:
                    # ServiceBusMessageBatch object reaches max_size.
                    # New ServiceBusMessageBatch object can be created here to send more data.
                    break
            # Send the batch of messages to the queue
            await sender.send_messages(batch_message)
        print("Sent a batch of 10 messages")
    
  6. Create a Service Bus client and then a queue sender object to send messages.

    async def run():
        # create a Service Bus client using the credential
        async with ServiceBusClient(
            fully_qualified_namespace=FULLY_QUALIFIED_NAMESPACE,
            credential=credential,
            logging_enable=True) as servicebus_client:
            # get a Queue Sender object to send messages to the queue
            sender = servicebus_client.get_queue_sender(queue_name=QUEUE_NAME)
            async with sender:
                # send one message
                await send_single_message(sender)
                # send a list of messages
                await send_a_list_of_messages(sender)
                # send a batch of messages
                await send_batch_message(sender)
    
            # Close credential when no longer needed.
            await credential.close()
    
  7. Call the run method and print a message.

    asyncio.run(run())
    print("Done sending messages")
    print("-----------------------")
    

Receive messages from a queue

The following sample code shows you how to receive messages from a queue. The code shown receives new messages until it doesn't receive any new messages for 5 (max_wait_time) seconds.

Open your favorite editor, such as Visual Studio Code, create a file recv.py, and add the following code into it.

  1. Similar to the send sample, add import statements, define constants that you should replace with your own values, and define a credential.

    import asyncio
    
    from azure.servicebus.aio import ServiceBusClient
    from azure.identity.aio import DefaultAzureCredential
    
    FULLY_QUALIFIED_NAMESPACE = "FULLY_QUALIFIED_NAMESPACE"
    QUEUE_NAME = "QUEUE_NAME"
    
    credential = DefaultAzureCredential()
    
  2. Create a Service Bus client and then a queue receiver object to receive messages.

    async def run():
        # create a Service Bus client using the connection string
        async with ServiceBusClient(
            fully_qualified_namespace=FULLY_QUALIFIED_NAMESPACE,
            credential=credential,
            logging_enable=True) as servicebus_client:
    
            async with servicebus_client:
                # get the Queue Receiver object for the queue
                receiver = servicebus_client.get_queue_receiver(queue_name=QUEUE_NAME)
                async with receiver:
                    received_msgs = await receiver.receive_messages(max_wait_time=5, max_message_count=20)
                    for msg in received_msgs:
                        print("Received: " + str(msg))
                        # complete the message so that the message is removed from the queue
                        await receiver.complete_message(msg)
    
            # Close credential when no longer needed.
            await credential.close()
    
  3. Call the run method.

    asyncio.run(run())
    

Run the app

Open a command prompt that has Python in its path, and then run the code to send and receive messages from the queue.

python send.py; python recv.py

You should see the following output:

Sent a single message
Sent a list of 5 messages
Sent a batch of 10 messages
Done sending messages
-----------------------
Received: Single Message
Received: Message in list
Received: Message in list
Received: Message in list
Received: Message in list
Received: Message in list
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch
Received: Message inside a ServiceBusMessageBatch

In the Azure portal, navigate to your Service Bus namespace. On the Overview page, verify that the incoming and outgoing message counts are 16. If you don't see the counts, refresh the page after waiting for a few minutes.

Incoming and outgoing message count

Select the queue on this Overview page to navigate to the Service Bus Queue page. You can also see the incoming and outgoing message count on this page. You also see other information such as the current size of the queue and active message count.

Queue details

Next steps

See the following documentation and samples: