Azure App Configuration: Centralized Settings Management

Azure App Configuration provides centralized configuration management. Feature flags, settings, and secrets—all in one place with change notifications.

Creating App Configuration

az appconfig create \
    --name my-app-config \
    --resource-group myRG \
    --location eastus \
    --sku Standard

Setting Configuration Values

# Set key-value
az appconfig kv set \
    --name my-app-config \
    --key "Settings:ApiEndpoint" \
    --value "https://api.example.com"

# Set with label (for environments)
az appconfig kv set \
    --name my-app-config \
    --key "Settings:ConnectionString" \
    --value "Server=dev-server" \
    --label "Development"

az appconfig kv set \
    --name my-app-config \
    --key "Settings:ConnectionString" \
    --value "Server=prod-server" \
    --label "Production"

# Reference Key Vault secret
az appconfig kv set-keyvault \
    --name my-app-config \
    --key "Settings:DatabasePassword" \
    --secret-identifier "https://myvault.vault.azure.net/secrets/db-password"

.NET Integration

// Program.cs
var builder = WebApplication.CreateBuilder(args);

// Add App Configuration
builder.Configuration.AddAzureAppConfiguration(options =>
{
    options.Connect(builder.Configuration["ConnectionStrings:AppConfig"])
        .Select(KeyFilter.Any, LabelFilter.Null)
        .Select(KeyFilter.Any, builder.Environment.EnvironmentName)
        .ConfigureKeyVault(kv => kv.SetCredential(new DefaultAzureCredential()))
        .ConfigureRefresh(refresh =>
        {
            refresh.Register("Settings:RefreshToken", refreshAll: true)
                   .SetCacheExpiration(TimeSpan.FromSeconds(30));
        })
        .UseFeatureFlags(flags =>
        {
            flags.CacheExpirationInterval = TimeSpan.FromMinutes(5);
        });
});

// Add middleware for refresh
builder.Services.AddAzureAppConfiguration();

var app = builder.Build();
app.UseAzureAppConfiguration();

// Inject configuration
public class MyService
{
    private readonly IConfiguration _config;

    public MyService(IConfiguration config)
    {
        _config = config;
    }

    public string GetApiEndpoint()
    {
        return _config["Settings:ApiEndpoint"];
    }
}

Feature Flags

# Create feature flag
az appconfig feature set \
    --name my-app-config \
    --feature "BetaFeature" \
    --label "Production"

# Enable/disable
az appconfig feature enable --name my-app-config --feature "BetaFeature"
az appconfig feature disable --name my-app-config --feature "BetaFeature"

Feature Flag Filters

{
    "id": "BetaFeature",
    "enabled": true,
    "conditions": {
        "client_filters": [
            {
                "name": "Percentage",
                "parameters": {
                    "Value": 25
                }
            },
            {
                "name": "Targeting",
                "parameters": {
                    "Audience": {
                        "Users": ["user1@company.com"],
                        "Groups": [
                            { "Name": "BetaTesters", "RolloutPercentage": 100 }
                        ],
                        "DefaultRolloutPercentage": 10
                    }
                }
            }
        ]
    }
}

Using Feature Flags

public class HomeController : Controller
{
    private readonly IFeatureManager _featureManager;

    public HomeController(IFeatureManager featureManager)
    {
        _featureManager = featureManager;
    }

    public async Task<IActionResult> Index()
    {
        if (await _featureManager.IsEnabledAsync("BetaFeature"))
        {
            return View("BetaIndex");
        }
        return View();
    }
}

<!-- In Razor views -->
<feature name="BetaFeature">
    <div class="beta-content">
        New Beta Feature!
    </div>
</feature>

Configuration Snapshots

# Create snapshot
az appconfig snapshot create \
    --name my-app-config \
    --snapshot-name "release-v1.0" \
    --filters '{key="Settings:*", label="Production"}'

# List snapshots
az appconfig snapshot list --name my-app-config

# Archive snapshot
az appconfig snapshot archive \
    --name my-app-config \
    --snapshot-name "release-v1.0"

Event Grid Integration

# Subscribe to configuration changes
az eventgrid event-subscription create \
    --name config-changes \
    --source-resource-id /subscriptions/.../appconfig/my-app-config \
    --endpoint https://myapp.com/webhook \
    --included-event-types Microsoft.AppConfiguration.KeyValueModified

App Configuration: dynamic settings without redeployment.