Delete a Blob

This guide explains how to delete blobs from an Azure Storage account using various methods.

Understanding Blob Deletion

Deleting a blob removes the blob and all its committed versions from your Azure Storage account. Once a blob is deleted, it cannot be recovered unless versioning is enabled and a previous version is still available. It's important to ensure you have backups or versioning configured if data loss is a concern.

Prerequisites

• An Azure Storage account.
• A container within your storage account.
• A blob to delete within the container.
• Appropriate permissions to delete blobs (e.g., Storage Blob Data Owner role).

Methods for Deleting a Blob

1. Using the Azure Portal

The Azure portal provides a user-friendly interface for managing your storage resources.

1. Navigate to your Azure Storage account in the Azure portal.
2. Select Containers from the left-hand menu under the "Data storage" section.
3. Click on the container that holds the blob you want to delete.
4. Locate the blob in the list. You can use the search or filter options if needed.
5. Select the checkbox next to the blob you want to delete. You can select multiple blobs at once.
6. Click the Delete button in the toolbar.
7. A confirmation dialog will appear. Type delete in the confirmation field and click Delete to proceed.

2. Using Azure CLI

The Azure Command-Line Interface (CLI) is a powerful tool for automating tasks.

First, ensure you are logged in to your Azure account:

az login

To delete a blob, use the az storage blob delete command:

az storage blob delete \
    --account-name  \
    --container-name  \
    --name  \
    --auth-mode login  # Or use --account-key if you have it

Replace the placeholders with your actual storage account name, container name, and blob name.

3. Using Azure PowerShell

Azure PowerShell offers cmdlets for managing Azure resources.

First, connect to your Azure account:

Connect-AzAccount

To delete a blob, use the Remove-AzStorageBlob cmdlet:

Remove-AzStorageBlob `
    -Context (Get-AzStorageAccount `
        -ResourceGroupName "" `
        -Name "") `
    -Container  `
    -Blob 

Alternatively, you can use the account key for authentication:

$sa = Get-AzStorageAccount -ResourceGroupName "" -Name ""
$ctx = $sa.Context
Remove-AzStorageBlob -Blob  -Container  -Context $ctx

4. Using .NET SDK

Delete a blob programmatically using the Azure Storage SDK for .NET.

using Azure.Storage.Blobs;
using System;

// Replace with your connection string
string connectionString = "";
string containerName = "";
string blobName = "";

try
{
    // Create a BlobServiceClient object
    BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);

    // Get a reference to the container client
    BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient(containerName);

    // Get a reference to the blob client
    BlobClient blobClient = containerClient.GetBlobClient(blobName);

    // Delete the blob
    Response response = await blobClient.DeleteIfExistsAsync();

    if (response.Value)
    {
        Console.WriteLine($"Blob '{blobName}' deleted successfully.");
    }
    else
    {
        Console.WriteLine($"Blob '{blobName}' not found or could not be deleted.");
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Error deleting blob: {ex.Message}");
}

5. Using REST API

You can also delete blobs directly using the Azure Storage REST API.

Make a DELETE request to the blob's URI:

DELETE https://myaccount.blob.core.windows.net/mycontainer/myblob.txt?sv=2019-02-02&st=2019-02-02T22%3A00%3A00Z&se=2019-02-02T22%3A00%3A00Z&sr=b&sp=w&sig=abcdefghijklmnopqrstuvwxyz0123456789

This example uses a Shared Access Signature (SAS) for authorization. Alternatively, you can use other authorization methods like OAuth.

Deleting Multiple Blobs

To delete multiple blobs efficiently, consider the following:

• Azure CLI/PowerShell: You can use wildcards or loops to delete multiple blobs matching a pattern.
• SDKs: Iterate through blobs and call the delete method for each.
• Batch Operations: For very large-scale deletions, explore batch operations if available for specific SDKs or use tools designed for bulk operations.

Considerations

• Permissions: Ensure you have the necessary permissions to delete.
• Versioning: If blob versioning is enabled, deleting the current version does not permanently remove the data; it makes a previous version current.
• Soft Delete: Understand how soft delete impacts recovery. Deleted blobs are retained for a configurable period.
• Leased Blobs: You cannot delete a blob that has an active lease unless you break the lease first.