Azure Storage Blobs

Azure Blob Storage is Microsoft's object storage solution for the cloud. It is optimized for storing massive amounts of unstructured data, such as text or binary data. Unstructured data is data that doesn't adhere to a particular data model or definition, such as text or binary files.

What are Blobs?

Blobs can be used to serve images or documents directly to a browser, to store files for direct download, to store data for backup and restore, disaster recovery, and data archiving, or to write to log data for analysis.

Tip: For large-scale data analytics, consider using Azure Data Lake Storage Gen2, which builds on Azure Blob Storage.

Blob Types

Azure Blob Storage supports three types of blobs:

Key Concepts

Storage Account

A storage account provides a unique namespace in Azure for your data. Every object that you store in Azure Storage has a direct or indirect reference to a storage account. The combination of the storage account name and the blob name uniquely identifies any blob in the world.

Containers

A container is a logical grouping of blobs. You must create a container before you can upload any blobs. You can organize blobs within a container like files in a directory.

Access Tiers

Azure Blob Storage offers different access tiers to optimize costs for data that is accessed with varying frequency. These tiers include:

Common Operations

Here are some of the most common operations you can perform with Azure Blob Storage:

Creating a Container

You can create a container using Azure Portal, Azure CLI, or SDKs. The container name must start with a letter or number, and can contain only letters, numbers, and the dash (-) character. It must be between 3 and 63 characters long.

Uploading a Blob

You can upload block blobs, append blobs, or page blobs. The method for uploading depends on the blob type and the client library used.

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

public class BlobUploader
{
    public async Task UploadBlobAsync(string connectionString, string containerName, string blobName, string filePath)
    {
        var blobServiceClient = new BlobServiceClient(connectionString);
        var blobContainerClient = blobServiceClient.GetBlobContainerClient(containerName);
        await blobContainerClient.CreateIfNotExistsAsync();

        var blobClient = blobContainerClient.GetBlobClient(blobName);
        using var fileStream = File.OpenRead(filePath);
        await blobClient.UploadAsync(fileStream, true);
        Console.WriteLine($"Blob '{blobName}' uploaded successfully.");
    }
}

Downloading a Blob

You can download blob content to a file or a stream.

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

def download_blob(connection_string, container_name, blob_name, output_path):
    blob_service_client = BlobServiceClient.from_connection_string(connection_string)
    container_client = blob_service_client.get_container_client(container_name)
    blob_client = container_client.get_blob_client(blob_name)

    with open(output_path, "wb") as download_file:
        download_stream = blob_client.download_blob()
        download_stream.readinto(download_file)
    print(f"Blob '{blob_name}' downloaded to {output_path}")

# Example usage:
# conn_str = "YOUR_CONNECTION_STRING"
# container = "mycontainer"
# blob = "myblob.txt"
# output_file = "downloaded_myblob.txt"
# download_blob(conn_str, container, blob, output_file)

Security Considerations

When working with Azure Blob Storage, it's crucial to implement strong security measures:

Important: Never embed storage account keys directly in client-side code or public repositories.

Performance and Scalability

Azure Blob Storage is designed for high availability and massive scalability. You can leverage features like:

Further Reading