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How to use Azure App Configuration SDK with Topaz

This guide shows you how to use the Azure App Configuration SDK against a locally emulated App Configuration store provided by Topaz.

Prerequisites​

  • Topaz installed and the certificate trusted at the OS level (see Getting started)
  • .NET 8 or later

Step 1 — Add NuGet packages​

dotnet add package Topaz.AspNetCore.Extensions
dotnet add package Topaz.ResourceManager
dotnet add package Testcontainers.Topaz
dotnet add package Microsoft.Azure.AppConfiguration.AspNetCore
dotnet add package Azure.ResourceManager.AppConfiguration

Step 2 — Start Topaz and provision resources​

Spin up a Topaz container and create a subscription, resource group, and App Configuration store before the application starts:

var container = new TopazBuilder(useNightlyImage: true).Build();

await container.StartAsync();
await Task.Delay(5000); // wait for Topaz to be ready

var credentials = new AzureLocalCredential(Globals.GlobalAdminId);
var subscriptionId = Guid.NewGuid();
const string resourceGroupName = "rg-myapp";
const string storeName = "myappconfig";

var resourceGroupIdentifier = ResourceGroupIdentifier.From(resourceGroupName);

await builder.Configuration.AddTopaz(subscriptionId, Globals.GlobalAdminId)
    .AddSubscription(subscriptionId, "myapp", credentials)
    .AddResourceGroup(subscriptionId, resourceGroupName, AzureLocation.WestEurope)
    .AddConfigurationStore(
        resourceGroupIdentifier,
        storeName,
        new AppConfigurationStoreData(AzureLocation.WestEurope, new AppConfigurationSku("Standard")))
    .AddKeyValuesToStore(resourceGroupIdentifier, storeName, "MyApp:Setting1", "hello")
    .AddKeyValuesToStore(resourceGroupIdentifier, storeName, "MyApp:Setting2", Guid.NewGuid().ToString());

Step 3 — Connect the SDK to the emulated store​

Use TopazResourceHelpers.GetAppConfigurationStoreEndpoint to resolve the local endpoint, then connect with AzureLocalCredential:

var appConfigEndpoint = TopazResourceHelpers.GetAppConfigurationStoreEndpoint(storeName);

builder.Configuration.AddAzureAppConfiguration(options =>
{
    options.Connect(new Uri(appConfigEndpoint), new AzureLocalCredential(Globals.GlobalAdminId))
        .Select("MyApp:*")
        .ConfigureRefresh(refresh =>
        {
            refresh.RegisterAll();
        })
        .UseFeatureFlags();
});

builder.Services.AddAzureAppConfiguration();

Step 4 — Read configuration values​

Configuration values loaded from the emulated store are available through IConfiguration like any other provider:

app.MapGet("/config", (IConfiguration configuration) =>
{
    return configuration.GetSection("MyApp").AsEnumerable();
});

Replica support​

Topaz supports App Configuration replicas. Add a replica to a different region during provisioning:

.AddConfigurationStoreReplica(
    resourceGroupIdentifier,
    storeName,
    "ne",
    new AppConfigurationReplicaData { Location = AzureLocation.NorthEurope })

Then enable replica discovery and load balancing in the SDK options:

builder.Configuration.AddAzureAppConfiguration(options =>
{
    options.ReplicaDiscoveryEnabled = true;
    options.LoadBalancingEnabled = true;
    options.Connect(new Uri(appConfigEndpoint), new AzureLocalCredential(Globals.GlobalAdminId))
        .Select("MyApp:*");
});

Full example​

A runnable example combining App Configuration, Key Vault, and Storage is available in the Topaz repository under Examples/Topaz.Example.Dotnet.Web.

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