Configuring SignalR + StackExchangeRedis for Azure Managed Redis and Managed Identity auth

[Lindsay Mathieson (Lindsay-Mathieson)]

All of the above created via Aspire and deployment to app services.

AppHost:

// Azure Managed Redis Cache (Premium) for caching and session state management
var redisCache = builder.AddAzureManagedRedis("rediscache")
    .RunAsContainer()
    .ConfigureInfrastructure(infra =>
    {
        var cache = infra.GetProvisionableResources()
                              .OfType<RedisEnterpriseCluster>()
                              .Single();

        cache.Sku = new RedisEnterpriseSku
        {
            Name = RedisEnterpriseSkuName.BalancedB0,       
            //Capacity = 1,
        };
        cache.Tags["Environment"] = "Development";
        cache.Tags["CostCenter"] = "Engineering";
        cache.HighAvailability = RedisEnterpriseHighAvailability.Disabled;
        cache.PublicNetworkAccess = RedisEnterprisePublicNetworkAccess.Enabled;
    });

In my web app that runs a signalr server I had:

// Redis EntraId Authentication
builder.AddRedisClientBuilder("rediscache")
    .WithAzureAuthentication();


// SignalR
var signalr = builder.Services.AddSignalR();
signalr.AddStackExchangeRedis(options("rediscache");

That did work due to auth failures in Azure (worked fine in local dev). I updated it to:

// Redis EntraId Authentication
builder.AddRedisClientBuilder("rediscache")
    .WithAzureAuthentication();


// SignalR
var signalr = builder.Services.AddSignalR();

signalr.AddStackExchangeRedis(options =>
{
    var redisEndpoint = Environment.GetEnvironmentVariable("ConnectionStrings__rediscache") ?? "";
    options.Configuration.ChannelPrefix = RedisChannel.Literal("signalr");
    options.ConnectionFactory = async writer =>
    {
        System.Console.WriteLine($"Connecting to Redis at {redisEndpoint}");
        var configurationOptions = ConfigurationOptions.Parse(redisEndpoint);
        configurationOptions.AbortOnConnectFail = false;

        // 1. Detect Azure App Service
        bool isAppService = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("WEBSITE_SITE_NAME"));

        // 2. Detect Azure Container Apps (ACA)
        bool isContainerApps = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CONTAINER_APP_NAME"));

        // 3. General Azure Check
        bool isRunningInAzure = isAppService || isContainerApps;


        if (isRunningInAzure)
        {
            // DefaultAzureCredential
            Console.WriteLine("Configuring StackExchangeRedis for Azure with DefaultAzureCredential");
            await configurationOptions.ConfigureForAzureWithTokenCredentialAsync(new Azure.Identity.DefaultAzureCredential());
        }
        else
        {
            // Local Development
            Console.WriteLine("Configuring StackExchangeRedis for local development with connection string");
        }
        var mux = await ConnectionMultiplexer.ConnectAsync(configurationOptions);
        return mux;
    };
});

This appears to be working - is it the correct way to use aspire default managed auth?

Thanks - Lindsay