How to Use Azure Blob Storage

This guide provides practical examples and step-by-step instructions on how to interact with Azure Blob Storage using various tools and SDKs. We'll cover common operations like uploading, downloading, listing, and managing blobs.

Prerequisites

Before you begin, ensure you have the following:

1. Using the Azure Portal

The Azure portal offers a user-friendly graphical interface for managing your blobs.

  1. Navigate to your storage account in the Azure portal.
  2. Under "Data storage", select "Containers".
  3. Click "+ Container" to create a new container.
  4. Select a container and click "Upload" to upload a new blob.
  5. You can click on a blob to view its properties, download it, or delete it.

2. Using Azure CLI

The Azure Command-Line Interface (CLI) is a powerful tool for scripting and automating storage operations.

a) Login to Azure

az login

b) Set Your Subscription (if needed)

az account set --subscription ""

c) Upload a Blob

Upload a file named my-local-file.txt to a container named mycontainer.

az storage blob upload \
    --account-name  \
    --container-name mycontainer \
    --name my-remote-file.txt \
    --file my-local-file.txt \
    --connection-string ""

d) Download a Blob

Download a blob named my-remote-file.txt from mycontainer to downloaded-file.txt.

az storage blob download \
    --account-name  \
    --container-name mycontainer \
    --name my-remote-file.txt \
    --file downloaded-file.txt \
    --connection-string ""

e) List Blobs in a Container

az storage blob list \
    --account-name  \
    --container-name mycontainer \
    --connection-string ""

3. Using Azure Storage SDKs

Azure provides SDKs for various programming languages to interact with Blob Storage programmatically. Here are examples using Python and .NET.

a) Python SDK

First, install the SDK:

pip install azure-storage-blob

Example: Uploading a Blob

Python Upload Example

from azure.storage.blob import BlobServiceClient

            connect_str = ""
            blob_service_client = BlobServiceClient.from_connection_string(connect_str)

            container_name = "mycontainer"
            local_file_name = "local_upload.txt"
            blob_name = "remote_upload.txt"

            try:
                # Create a blob client using the container name
                container_client = blob_service_client.get_container_client(container_name)

                # Create a local file for upload
                with open(local_file_name, "w") as my_file:
                    my_file.write("This is a test file for Azure Blob Storage upload.")

                # Upload the blob
                with open(local_file_name, "rb") as data:
                    container_client.upload_blob(name=blob_name, data=data)
                print(f"Blob '{blob_name}' uploaded successfully.")

            except Exception as ex:
                print('Exception:')
                print(ex)

b) .NET SDK

First, install the NuGet package:

Install-Package Azure.Storage.Blobs

Example: Downloading a Blob

C# Download Example

using Azure.Storage.Blobs;
            using System;
            using System.IO;

            public class BlobDownloader
            {
                public static void DownloadBlob(string connectionString, string containerName, string blobName, string localFilePath)
                {
                    try
                    {
                        BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
                        BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient(containerName);
                        BlobClient blobClient = containerClient.GetBlobClient(blobName);

                        using (FileStream downloadFileStream = File.OpenWrite(localFilePath))
                        {
                            Response<Response> downloadResult = blobClient.DownloadTo(downloadFileStream);
                            Console.WriteLine($"Blob '{blobName}' downloaded successfully to '{localFilePath}'.");
                        }
                    }
                    catch (RequestFailedException e)
                    {
                        Console.WriteLine($"Error downloading blob: {e.Message}");
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine($"An unexpected error occurred: {e.Message}");
                    }
                }

                public static void Main(string[] args)
                {
                    string connectionString = "";
                    string containerName = "mycontainer";
                    string blobName = "remote_upload.txt";
                    string localFilePath = "downloaded_from_azure.txt";

                    DownloadBlob(connectionString, containerName, blobName, localFilePath);
                }
            }

Key Concepts

Tip: For secure access, consider using Azure AD authentication or Shared Access Signatures (SAS) instead of account keys for production applications.
Note: Blob storage offers different access tiers (Hot, Cool, Archive) which can help optimize costs based on access frequency.

Further Reading