Download a Blob from Azure Storage

This document explains how to download a blob from an Azure Storage account using various methods, including Azure portal, Azure CLI, PowerShell, and SDKs.

Overview

Downloading a blob involves retrieving its content from Azure Blob Storage and saving it to a local destination. This can be done for individual blobs or for an entire container.

Prerequisites

• An Azure subscription.
• An Azure Storage account.
• A container within your storage account.
• A blob uploaded to the container that you wish to download.

Methods for Downloading Blobs

1. Using the Azure Portal

The Azure portal provides a user-friendly interface for downloading blobs.

1. Navigate to your storage account in the Azure portal.
2. Select Containers under Data storage.
3. Click on the container that holds the blob you want to download.
4. Locate the blob in the list and click the Download button next to it.

2. Using Azure CLI

The Azure Command-Line Interface (CLI) is a powerful tool for managing Azure resources. To download a blob, use the az storage blob download command.

az storage blob download \
    --account-name  \
    --container-name  \
    --name  \
    --file  \
    --auth-mode login
            

Replace the placeholders with your specific values. --auth-mode login uses your Azure AD credentials for authentication.

3. Using Azure PowerShell

Azure PowerShell offers cmdlets for managing storage. Use the Get-AzStorageBlobContent cmdlet to download a blob.

$ctx = New-AzStorageContext -StorageAccountName "" -StorageAccountKey ""
            Get-AzStorageBlobContent -Container "" -Blob "" -Destination "" -Context $ctx
            

Alternatively, you can use managed identity or other authentication methods.

4. Using Azure Storage SDKs

Azure Storage SDKs are available for various programming languages (e.g., .NET, Java, Python, Node.js) to programmatically download blobs.

Example (Python SDK):

from azure.storage.blob import BlobServiceClient

connection_string = "YOUR_CONNECTION_STRING"
container_name = "your-container-name"
blob_name = "your-blob-name.txt"
local_file_path = "downloaded_blob.txt"

try:
    blob_service_client = BlobServiceClient.from_connection_string(connection_string)
    blob_client = blob_service_client.get_blob_client(container=container_name, blob=blob_name)

    with open(local_file_path, "wb") as download_file:
        download_file.write(blob_client.download_blob().readall())
    print(f"Blob '{blob_name}' downloaded successfully to '{local_file_path}'.")

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

Refer to the official Azure Storage SDK documentation for specific language implementations.