Get started with Azure Blob Storage and Python

Article
07/12/2023

This article shows you how to connect to Azure Blob Storage by using the Azure Blob Storage client library for Python. Once connected, your code can operate on containers, blobs, and features of the Blob Storage service.

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Prerequisites

Azure subscription - create one for free
Azure storage account - create a storage account
Python 3.7+

Set up your project

This section walks you through preparing a project to work with the Azure Blob Storage client library for Python.

From your project directory, install packages for the Azure Blob Storage and Azure Identity client libraries using the pip install command. The azure-identity package is needed for passwordless connections to Azure services.

pip install azure-storage-blob azure-identity

Then open your code file and add the necessary import statements. In this example, we add the following to our .py file:

from azure.identity import DefaultAzureCredential
from azure.storage.blob import BlobServiceClient, BlobClient, ContainerClient

Blob client library information:

azure.storage.blob: Contains the primary classes (client objects) that you can use to operate on the service, containers, and blobs.

Authorize access and connect to Blob Storage

To connect an application to Blob Storage, create an instance of the BlobServiceClient class. This object is your starting point to interact with data resources at the storage account level. You can use it to operate on the storage account and its containers. You can also use the service client to create container clients or blob clients, depending on the resource you need to work with.

To learn more about creating and managing client objects, see Create and manage client objects that interact with data resources.

You can authorize a BlobServiceClient object by using an Azure Active Directory (Azure AD) authorization token, an account access key, or a shared access signature (SAS).

To authorize with Azure AD, you'll need to use a security principal. Which type of security principal you need depends on where your application runs. Use the following table as a guide:

Where the application runs	Security principal	Guidance
Local machine (developing and testing)	Service principal	To learn how to register the app, set up an Azure AD group, assign roles, and configure environment variables, see Authorize access using developer service principals
Local machine (developing and testing)	User identity	To learn how to set up an Azure AD group, assign roles, and sign in to Azure, see Authorize access using developer credentials
Hosted in Azure	Managed identity	To learn how to enable managed identity and assign roles, see Authorize access from Azure-hosted apps using a managed identity
Hosted outside of Azure (for example, on-premises apps)	Service principal	To learn how to register the app, assign roles, and configure environment variables, see Authorize access from on-premises apps using an application service principal

Authorize access using DefaultAzureCredential

An easy and secure way to authorize access and connect to Blob Storage is to obtain an OAuth token by creating a DefaultAzureCredential instance. You can then use that credential to create a BlobServiceClient object.

The following example creates a BlobServiceClient object using DefaultAzureCredential:

def get_blob_service_client_token_credential(self):
    # TODO: Replace <storage-account-name> with your actual storage account name
    account_url = "https://<storage-account-name>.blob.core.windows.net"
    credential = DefaultAzureCredential()

    # Create the BlobServiceClient object
    blob_service_client = BlobServiceClient(account_url, credential=credential)

    return blob_service_client

To use a shared access signature (SAS) token, provide the token as a string and initialize a BlobServiceClient object. If your account URL includes the SAS token, omit the credential parameter.

def get_blob_service_client_sas(self, sas_token: str):
    # TODO: Replace <storage-account-name> with your actual storage account name
    account_url = "https://<storage-account-name>.blob.core.windows.net"
    # The SAS token string can be assigned to credential here or appended to the account URL
    credential = sas_token

    # Create the BlobServiceClient object
    blob_service_client = BlobServiceClient(account_url, credential=credential)

    return blob_service_client

To learn more about generating and managing SAS tokens, see the following articles:

To use a storage account shared key, provide the key as a string and initialize a BlobServiceClient object.

def get_blob_service_client_account_key(self):
    # TODO: Replace <storage-account-name> with your actual storage account name
    account_url = "https://<storage-account-name>.blob.core.windows.net"
    shared_access_key = os.getenv("AZURE_STORAGE_ACCESS_KEY")
    credential = shared_access_key

    # Create the BlobServiceClient object
    blob_service_client = BlobServiceClient(account_url, credential=credential)

    return blob_service_client

You can also create a BlobServiceClient object using a connection string.

def get_blob_service_client_connection_string(self):
    # TODO: Replace <storage-account-name> with your actual storage account name
    account_url = "https://<storage-account-name>.blob.core.windows.net"
    connection_string = os.getenv("AZURE_STORAGE_CONNECTION_STRING")

    # Create the BlobServiceClient object
    blob_service_client = BlobServiceClient.from_connection_string(connection_string)

    return blob_service_client

For information about how to obtain account keys and best practice guidelines for properly managing and safeguarding your keys, see Manage storage account access keys.

Important

The account access key should be used with caution. If your account access key is lost or accidentally placed in an insecure location, your service may become vulnerable. Anyone who has the access key is able to authorize requests against the storage account, and effectively has access to all the data. DefaultAzureCredential provides enhanced security features and benefits and is the recommended approach for managing authorization to Azure services.

Build your application

As you build applications to work with data resources in Azure Blob Storage, your code primarily interacts with three resource types: storage accounts, containers, and blobs. To learn more about these resource types, how they relate to one another, and how apps interact with resources, see Understand how apps interact with Blob Storage data resources.

The following guides show you how to work with data resources and perform specific actions using the Azure Storage client library for Python:

Guide	Description
Create a container	Create containers.
Delete and restore containers	Delete containers, and if soft-delete is enabled, restore deleted containers.
List containers	List containers in an account and the various options available to customize a listing.
Manage properties and metadata (containers)	Get and set properties and metadata for containers.
Create and manage container leases	Establish and manage a lock on a container.
Create and manage blob leases	Establish and manage a lock on a blob.
Upload blobs	Learn how to upload blobs by using strings, streams, file paths, and other methods.
Download blobs	Download blobs by using strings, streams, and file paths.
Copy blobs	Copy a blob from one location to another.
List blobs	List blobs in different ways.
Delete and restore	Delete blobs, and if soft-delete is enabled, restore deleted blobs.
Find blobs using tags	Set and retrieve tags as well as use tags to find blobs.
Manage properties and metadata (blobs)	Get and set properties and metadata for blobs.
Set or change a blob's access tier	Set or change the access tier for a block blob.