Read Secrets at Start up Time for Asp.NET APIs

Kubernetes-read-secrets-at-start-up.cs

Host.CreateDefaultBuilder(args)
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
    })
    .ConfigureAppConfiguration((context, config) =>
    {
        var builtConfig = config.SetBasePath(Directory.GetCurrentDirectory())
                        .AddJsonFile("appsettings.json", false)
                        .AddJsonFile($"appsettings.Production.json", true)
                        .AddEnvironmentVariables()
                        .Build();
        var settings = builtConfig.Get<AppSettings>();

        if (settings.ContainerMode)
        {
            if (context.HostingEnvironment.IsProduction())
            {
                //1: Add plain secrets (no configs) as Opaque secrets
                //2: Secrets are accessible through separate files
                //3: Read the secret map values CSI volume of KeyVault provider
                config.AddKeyPerFile($"/root/.microsoft/usersecrets");
            }
        }
    });