Sample2_BackupAndRestoreAsync.cs

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See License.txt in the project root for
// license information.

using Azure.Identity;
using NUnit.Framework;
using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Azure.Security.KeyVault.Secrets.Samples
{
    /// <summary>
    /// Sample demonstrates how to backup and restore secrets in the key vault using the 
    /// asynchronous methods of the SecretClient.
    /// </summary>
    [Category("Live")]
    public partial class BackupAndRestore
    {
        [Test]
        [Ignore("https://github.com/Azure/azure-sdk-for-net/issues/6514")]
        public async Task BackupAndRestoreAsync()
        {
            // Environment variable with the Key Vault endpoint.
            string keyVaultUrl = Environment.GetEnvironmentVariable("AZURE_KEYVAULT_URL");
            string backupPath = Path.GetTempFileName();

            // Instantiate a secret client that will be used to call the service. Notice that the client is using default Azure
            // credentials. To make default credentials work, ensure that environment variables 'AZURE_CLIENT_ID',
            // 'AZURE_CLIENT_KEY' and 'AZURE_TENANT_ID' are set with the service principal credentials.
            var client = new SecretClient(new Uri(keyVaultUrl), new DefaultAzureCredential());

            // Let's create a secret holding bank account credentials valid for 1 year. if the secret
            // already exists in the key vault, then a new version of the secret is created.
            string secretName = $"StorageAccountPasswor{Guid.NewGuid()}";

            var secret = new Secret(secretName, "f4G34fMh8v")
            {
                Expires = DateTimeOffset.Now.AddYears(1)
            };

            Secret storedSecret = await client.SetAsync(secret);

            // Backups are good to have if in case secrets get accidentally deleted by you.
            // For long term storage, it is ideal to write the backup to a file.
            using (FileStream sourceStream = File.Open(backupPath, FileMode.OpenOrCreate))
            {
                byte[] byteSecret = await client.BackupAsync(secretName);
                sourceStream.Seek(0, SeekOrigin.End);
                await sourceStream.WriteAsync(byteSecret, 0, byteSecret.Length);
            }
            
            // The storage account secret is no longer in use, so you delete it.
            await client.DeleteAsync(secretName);

            // To ensure secret is deleted on server side.
            Assert.IsTrue(await WaitForDeletedSecretAsync(client, secretName));

            // If the keyvault is soft-delete enabled, then for permanent deletion, deleted secret needs to be purged.
            await client.PurgeDeletedAsync(secretName);

            // After sometime, the secret is required again. We can use the backup value to restore it in the key vault.
            SecretBase restoreSecret = null;
            using (FileStream sourceStream = File.Open(backupPath, FileMode.Open))
            {
                byte[] result = new byte[sourceStream.Length];
                await sourceStream.ReadAsync(result, 0, (int)sourceStream.Length);
                restoreSecret = await client.RestoreAsync(result);
            }

            AssertSecretsEqual((SecretBase)storedSecret, restoreSecret);
        }

        private async Task<bool> WaitForDeletedSecretAsync(SecretClient client, string secretName)
        {
            int maxIterations = 20;
            for (int i = 0; i < maxIterations; i++)
            {
                try
                {
                    await client.GetDeletedAsync(secretName);
                    return true;
                }
                catch
                {
                    Thread.Sleep(5000);
                }
            }
            return false;
        }
    }
}