Refactor AzLocal emulator for configurability and defaults

src/AzLocal.Client/AzlocalClientFactory.cs

@@ -1,3 +1,4 @@
+using AzLocal.Core;
 using Azure.Security.KeyVault.Secrets;
 using Azure.Storage.Blobs;
 using Azure.Storage.Blobs.Models;
@@ -12,7 +13,7 @@ namespace AzLocal.Client;
 public sealed class AzlocalClientFactory
 {
     private readonly string _baseUrl;
-    private const string DefaultBaseUrl = "http://localhost:4566";
+    private const string DefaultBaseUrl = EmulatorDefaults.BaseUrl;
 
     /// <summary>The credential that satisfies Azure SDK authentication against the local emulator.</summary>
     public AzlocalCredential Credential { get; } = new();
@@ -108,7 +109,7 @@ public HttpClient CreateServiceBusHttpClient(string @namespace)
             BaseAddress = new Uri($"{_baseUrl}/sb/{@namespace}/")
         };
         client.DefaultRequestHeaders.Authorization =
-            new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", "fake-azlocal-token");
+            new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", AzlocalCredential.TokenValue);
         return client;
     }
 
@@ -124,7 +125,7 @@ public HttpClient CreateHttpClient()
     {
         var client = new HttpClient { BaseAddress = new Uri(_baseUrl) };
         client.DefaultRequestHeaders.Authorization =
-            new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", "fake-azlocal-token");
+            new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", AzlocalCredential.TokenValue);
         return client;
     }
 

src/AzLocal.Client/AzlocalCredential.cs

@@ -1,3 +1,4 @@
+using AzLocal.Core;
 using Azure.Core;
 
 namespace AzLocal.Client;
@@ -9,8 +10,10 @@ namespace AzLocal.Client;
 /// </summary>
 public sealed class AzlocalCredential : TokenCredential
 {
-    // Matches the token returned by ImdsMiddleware so the SDK sees a consistent value.
-    private static readonly AccessToken Token = new("fake-azlocal-token", DateTimeOffset.MaxValue);
+    // Token value is shared with ImdsMiddleware via EmulatorDefaults — they must always match.
+    public static readonly string TokenValue = EmulatorDefaults.FakeToken;
+
+    private static readonly AccessToken Token = new(TokenValue, DateTimeOffset.MaxValue);
 
     public override AccessToken GetToken(TokenRequestContext requestContext, CancellationToken cancellationToken)
         => Token;

src/AzLocal.Core/EmulatorDefaults.cs

@@ -0,0 +1,14 @@
+namespace AzLocal.Core;
+
+/// <summary>
+/// Single source of truth for default values shared across the emulator host and client library.
+/// All defaults match the values in appsettings.json — change them there to override at runtime.
+/// </summary>
+public static class EmulatorDefaults
+{
+    public const string FakeToken      = "fake-azlocal-token";
+    public const string BaseUrl        = "http://localhost:4566";
+    public const string ObjectId       = "00000000-0000-0000-0000-000000000001";
+    public const string TenantId       = "00000000-0000-0000-0000-000000000002";
+    public const string SubscriptionId = "00000000-0000-0000-0000-000000000001";
+}

src/AzLocal.Host/Program.cs

@@ -22,11 +22,12 @@
     app.Logger.LogInformation("Registered service: {ServiceName}", handler.ServiceName);
 }
 
+var baseUrl = app.Configuration["AzLocal:BaseUrl"] ?? "http://localhost:4566";
 app.MapGet("/", () => new
 {
     status  = "AzLocal emulator running",
     version = "1.0",
-    docs    = "http://localhost:4566/"
+    docs    = $"{baseUrl}/"
 });
 
 app.Run();

src/AzLocal.Host/appsettings.json

@@ -10,11 +10,14 @@
   "AzLocal": {
     "StateMode": "InMemory",
     "BaseUrl": "http://localhost:4566",
+    "FakeToken": "fake-azlocal-token",
+    "ObjectId": "00000000-0000-0000-0000-000000000001",
+    "TenantId": "00000000-0000-0000-0000-000000000002",
+    "SubscriptionId": "00000000-0000-0000-0000-000000000001",
+    "SubscriptionDisplayName": "AzLocal Dev Subscription",
+    "DefaultLocation": "eastus",
     "BlobStorePath": "",
     "SnapshotPath": "",
-    "SqlitePath": "",
-    "SubscriptionId": "00000000-0000-0000-0000-000000000001",
-    "TenantId": "00000000-0000-0000-0000-000000000002",
-    "DefaultLocation": "eastus"
+    "SqlitePath": ""
   }
 }

src/AzLocal.Middleware/AuthStubMiddleware.cs

@@ -1,4 +1,6 @@
+using AzLocal.Core;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Configuration;
 using System.Security.Claims;
 
 namespace AzLocal.Middleware;
@@ -7,26 +9,32 @@ namespace AzLocal.Middleware;
 /// Bypasses Azure AD authentication for local development.
 /// Injects a fake authenticated identity on every request so [Authorize] checks pass
 /// without needing a real Azure AD token or tenant.
+/// Identity values are read from <c>AzLocal:ObjectId</c> and <c>AzLocal:TenantId</c> in configuration.
 /// </summary>
 public class AuthStubMiddleware
 {
     private readonly RequestDelegate _next;
+    private readonly ClaimsPrincipal _fakeUser;
 
-    // Static so the same fake identity is reused on every request — no per-request allocation.
-    // authenticationType must be non-null/non-empty for IsAuthenticated to return true.
-    private static readonly ClaimsPrincipal FakeUser = new(new ClaimsIdentity(
-    [
-        new Claim("oid", "00000000-0000-0000-0000-000000000001"),  // fake Azure object ID
-        new Claim("tid", "00000000-0000-0000-0000-000000000002"),  // fake tenant ID
-        new Claim(ClaimTypes.Name, "azlocal-dev"),
-    ], authenticationType: "AzLocalStub"));
+    public AuthStubMiddleware(RequestDelegate next, IConfiguration config)
+    {
+        _next = next;
+        var objectId = config["AzLocal:ObjectId"] ?? EmulatorDefaults.ObjectId;
+        var tenantId = config["AzLocal:TenantId"] ?? EmulatorDefaults.TenantId;
 
-    public AuthStubMiddleware(RequestDelegate next) => _next = next;
+        // authenticationType must be non-null/non-empty for IsAuthenticated to return true.
+        _fakeUser = new ClaimsPrincipal(new ClaimsIdentity(
+        [
+            new Claim("oid", objectId),
+            new Claim("tid", tenantId),
+            new Claim(ClaimTypes.Name, "azlocal-dev"),
+        ], authenticationType: "AzLocalStub"));
+    }
 
     public async Task InvokeAsync(HttpContext context)
     {
         // Skip real token validation — stamp every request as authenticated locally.
-        context.User = FakeUser;
+        context.User = _fakeUser;
         await _next(context);
     }
 }

src/AzLocal.Middleware/ImdsMiddleware.cs

@@ -1,33 +1,42 @@
-using Microsoft.AspNetCore.Http;
+using AzLocal.Core;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Configuration;
 using System.Text.Json;
 
 namespace AzLocal.Middleware;
 
+/// <summary>
+/// Intercepts Azure IMDS (Instance Metadata Service) token requests so the Azure SDK
+/// can acquire a credential locally without a real Azure VM or managed identity.
+/// Token value is read from <c>AzLocal:FakeToken</c> in configuration.
+/// </summary>
 public class ImdsMiddleware
 {
     private readonly RequestDelegate _next;
+    private readonly string _fakeTokenJson;
 
-    private static readonly string FakeTokenJson = JsonSerializer.Serialize(new
+    public ImdsMiddleware(RequestDelegate next, IConfiguration config)
     {
-        access_token = "fake-azlocal-token",
-        expires_on = "99999999999",
-        resource = "https://management.azure.com/",
-        token_type = "Bearer"
-    });
-
-    public ImdsMiddleware(RequestDelegate next) => _next = next;
+        _next = next;
+        var token = config["AzLocal:FakeToken"] ?? EmulatorDefaults.FakeToken;
+        _fakeTokenJson = JsonSerializer.Serialize(new
+        {
+            access_token = token,
+            expires_on   = "99999999999",
+            resource     = "https://management.azure.com/",
+            token_type   = "Bearer"
+        });
+    }
 
     public async Task InvokeAsync(HttpContext context)
     {
         if (context.Request.Path.StartsWithSegments("/metadata/identity/oauth2/token"))
         {
             context.Response.ContentType = "application/json";
-            context.Response.StatusCode = 200;
-            await context.Response.WriteAsync(FakeTokenJson);
-            return; // Do NOT call _next — response is already written
+            context.Response.StatusCode  = 200;
+            await context.Response.WriteAsync(_fakeTokenJson);
+            return; // Do NOT call _next — response is already written.
         }
         await _next(context);
     }
 }
-
-

src/AzLocal.Services/Arm/SubscriptionHandler.cs

@@ -28,7 +28,7 @@ public SubscriptionHandler(IConfiguration config, ILogger<SubscriptionHandler> l
         _fakeSubscription = new
         {
             subscriptionId = _subscriptionId,
-            displayName    = "AzLocal Dev Subscription",
+            displayName    = config["AzLocal:SubscriptionDisplayName"] ?? "AzLocal Dev Subscription",
             state          = "Enabled",
             tenantId
         };