Azure Queue Storage Client Library for Python

Warnings

• breaking Major architectural changes occurred with the release of the v12 SDK. Older client libraries (e.g., `azure-storage` or `Microsoft.Azure.Storage.Queue`) are deprecated and no longer maintained. Applications must migrate to the `azure-storage-queue` package, which involves new client constructors, model names, and authentication patterns.
  Fix: Rewrite client initialization and interactions using the `azure-storage-queue` library. Prioritize passwordless authentication with `DefaultAzureCredential` over shared keys. Refer to the official migration guides.
• gotcha Messages sent to and received from Azure Queue Storage are often base64 encoded by default, especially when dealing with non-string content like JSON or binary data. Failing to explicitly encode before sending or decode after receiving can lead to corrupted data or deserialization errors.
  Fix: Always use `BinaryBase64EncodePolicy()` and `BinaryBase64DecodePolicy()` when creating `QueueServiceClient` or `QueueClient` if you intend to send/receive non-string data that requires base64 encoding/decoding. For JSON messages, ensure you explicitly `json.dumps()` before sending and `json.loads()` after decoding.
• gotcha Azure Queue Storage lacks a built-in dead-letter queue mechanism, unlike Azure Service Bus. If a message consistently fails processing, it will reappear in the queue after its visibility timeout expires. This can lead to a 'poison message' blocking workers indefinitely and requiring manual intervention.
  Fix: Implement custom dead-lettering logic by tracking retry counts. If a message exceeds a configured retry threshold, move it to a separate 'poison message' queue or log it for manual inspection and removal from the main queue.
• gotcha Using shared access keys or connection strings directly in application code is discouraged, especially in production. This poses a security risk and complicates key rotation.
  Fix: Migrate to passwordless authentication using Azure Identity. Leverage `DefaultAzureCredential` with Managed Identities for Azure-hosted applications or environment variables for local development. Ensure appropriate Azure RBAC roles (e.g., 'Storage Queue Data Contributor') are assigned.
• gotcha Incorrectly managing message visibility timeouts can lead to messages reappearing in the queue before processing is complete (leading to reprocessing) or being lost if the application crashes and the message is not explicitly deleted within the timeout.
  Fix: Adjust the `visibility_timeout` parameter when receiving messages to allow sufficient time for processing. If processing takes longer than expected, extend the visibility timeout using `update_message`. Ensure messages are deleted after successful processing.

Install

• pip install azure-storage-queue azure-identity Install with Azure Identity

Imports

• QueueServiceClient

  from azure.storage.queue import QueueServiceClient

  Old SDK versions might have used different class names or module structures. Always use the specific 'QueueServiceClient' for clarity and compatibility with the current SDK.
• QueueClient

  from azure.storage.queue import QueueClient

• DefaultAzureCredential

  from azure.identity import DefaultAzureCredential

  The `azure-identity` library with `DefaultAzureCredential` is the recommended modern approach for authentication, replacing older credential types and patterns in `azure.common`.
• BinaryBase64EncodePolicy

  from azure.storage.queue import BinaryBase64EncodePolicy

• BinaryBase64DecodePolicy

  from azure.storage.queue import BinaryBase64DecodePolicy

Quickstart

This quickstart demonstrates how to create a `QueueServiceClient` (using either a connection string or `DefaultAzureCredential`), create a queue, send messages, peek at messages, receive and delete messages, and finally delete the queue. It highlights the use of `BinaryBase64EncodePolicy` and `BinaryBase64DecodePolicy` for message handling. Ensure `AZURE_STORAGE_CONNECTION_STRING` or `AZURE_STORAGE_ACCOUNT_URL` and necessary Azure Identity environment variables (e.g., `AZURE_TENANT_ID`, `AZURE_CLIENT_ID`, `AZURE_CLIENT_SECRET`) are set for authentication.

import os, uuid
from azure.identity import DefaultAzureCredential
from azure.storage.queue import QueueServiceClient, QueueClient, BinaryBase64EncodePolicy, BinaryBase64DecodePolicy

try:
    print('Azure Queue storage - Python quickstart sample')

    # Retrieve the connection string for use with the application.
    # The storage connection string is a key for accessing your storage account.
    # It is recommended to use passwordless authentication in production.
    connect_str = os.environ.get('AZURE_STORAGE_CONNECTION_STRING', '')
    queue_name = "quickstart-" + str(uuid.uuid4())

    # Create the QueueServiceClient object
    if connect_str:
        # Authenticate with connection string
        queue_service_client = QueueServiceClient.from_connection_string(
            connect_str, 
            message_encode_policy=BinaryBase64EncodePolicy(),
            message_decode_policy=BinaryBase64DecodePolicy()
        )
        print("Using connection string for authentication.")
    else:
        # Authenticate with DefaultAzureCredential
        account_url = os.environ.get('AZURE_STORAGE_ACCOUNT_URL') # e.g., 'https://<account-name>.queue.core.windows.net'
        if not account_url:
            raise ValueError("Please set AZURE_STORAGE_CONNECTION_STRING or AZURE_STORAGE_ACCOUNT_URL environment variable.")

        credential = DefaultAzureCredential()
        queue_service_client = QueueServiceClient(
            account_url=account_url, 
            credential=credential,
            message_encode_policy=BinaryBase64EncodePolicy(),
            message_decode_policy=BinaryBase64DecodePolicy()
        )
        print("Using DefaultAzureCredential for authentication.")

    # Get a client to interact with the queue
    queue_client = queue_service_client.get_queue_client(queue_name)

    # Create a queue
    print(f"Creating queue: {queue_name}")
    queue_client.create_queue()

    # Send a message
    message1 = "Hello, Azure Queue!"
    print(f"Adding message: {message1}")
    queue_client.send_message(message1)

    message2 = "This is a second message."
    print(f"Adding message: {message2}")
    queue_client.send_message(message2)

    # Peek at messages
    print("Peeking at messages...")
    peeked_messages = queue_client.peek_messages(max_messages=5)
    for peeked_message in peeked_messages:
        print(f"Peeked message: {peeked_message.content}")

    # Receive and delete messages
    print("Receiving and deleting messages...")
    messages = queue_client.receive_messages(messages_per_page=1)
    for message in messages:
        print(f"Received message: {message.content}")
        queue_client.delete_message(message)
        print(f"Deleted message: {message.content}")

    print(f"Successfully completed the quickstart. Deleting queue: {queue_name}")
    queue_client.delete_queue()

except Exception as ex:
    print(f"Exception: {ex}")