Fix docker linux issue where ip address was not correctly identified.

src/AzureEventGridSimulator/Domain/Commands/ValidateAllSubscriptionsCommandHandler.cs

@@ -20,12 +20,12 @@ public class ValidateAllSubscriptionsCommandHandler : IRequestHandler<ValidateAl
     private readonly IHttpClientFactory _httpClientFactory;
     private readonly ILogger<ValidateAllSubscriptionsCommandHandler> _logger;
     private readonly SimulatorSettings _simulatorSettings;
-    private readonly ValidationIpAddress _validationIpAddress;
+    private readonly ValidationIpAddressProvider _validationIpAddress;
 
     public ValidateAllSubscriptionsCommandHandler(ILogger<ValidateAllSubscriptionsCommandHandler> logger,
                                                   IHttpClientFactory httpClientFactory,
                                                   SimulatorSettings simulatorSettings,
-                                                  ValidationIpAddress validationIpAddress)
+                                                  ValidationIpAddressProvider validationIpAddress)
     {
         _logger = logger;
         _httpClientFactory = httpClientFactory;

src/AzureEventGridSimulator/Infrastructure/ValidationIpAddressProvider.cs

@@ -0,0 +1,39 @@
+using System.Linq;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Net.Sockets;
+
+namespace AzureEventGridSimulator.Infrastructure;
+
+public class ValidationIpAddressProvider
+{
+    private static string _ipAddress;
+    private static readonly object _lock = new();
+
+    public string Create()
+    {
+        return (NetworkInterface.GetAllNetworkInterfaces()
+                                .SelectMany(o => o.GetIPProperties().DnsAddresses)
+                                .FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork &&
+                                                      !ip.ToString().StartsWith("172") &&
+                                                      !IPAddress.IsLoopback(ip)) ?? IPAddress.Loopback).ToString();
+    }
+
+    public override string ToString()
+    {
+        lock (_lock)
+        {
+            if (string.IsNullOrWhiteSpace(_ipAddress))
+            {
+                _ipAddress = Create();
+            }
+        }
+
+        return _ipAddress;
+    }
+
+    public static implicit operator string(ValidationIpAddressProvider d)
+    {
+        return d.ToString();
+    }
+}

src/AzureEventGridSimulator/Program.cs

@@ -75,34 +75,50 @@ await host.StartAsync(token)
 
     private static async Task OnApplicationStarted(IApplicationBuilder app, IHostApplicationLifetime lifetime)
     {
-        Log.Information("It's Alive !");
+        try
+        {
+            Log.Verbose("Started");
 
-        var simulatorSettings = (SimulatorSettings)app.ApplicationServices.GetService(typeof(SimulatorSettings));
+            var simulatorSettings = app.ApplicationServices.GetService<SimulatorSettings>();
 
-        if (simulatorSettings is null)
-        {
-            Log.Fatal("Settings are not found. The application will now exit");
-            lifetime.StopApplication();
-            return;
-        }
+            if (simulatorSettings is null)
+            {
+                Log.Fatal("Settings are not found. The application will now exit");
+                lifetime.StopApplication();
+                return;
+            }
 
-        if (!simulatorSettings.Topics.Any())
-        {
-            Log.Fatal("There are no configured topics. The application will now exit");
-            lifetime.StopApplication();
-            return;
-        }
+            if (!simulatorSettings.Topics.Any())
+            {
+                Log.Fatal("There are no configured topics. The application will now exit");
+                lifetime.StopApplication();
+                return;
+            }
 
-        if (simulatorSettings.Topics.All(o => o.Disabled))
-        {
-            Log.Fatal("All of the configured topics are disabled. The application will now exit");
-            lifetime.StopApplication();
-            return;
-        }
+            if (simulatorSettings.Topics.All(o => o.Disabled))
+            {
+                Log.Fatal("All of the configured topics are disabled. The application will now exit");
+                lifetime.StopApplication();
+                return;
+            }
+
+            var mediator = app.ApplicationServices.GetService<IMediator>();
+
+            if (mediator is null)
+            {
+                Log.Fatal("Required component was not found. The application will now exit");
+                lifetime.StopApplication();
+                return;
+            }
 
-        if (app.ApplicationServices.GetService(typeof(IMediator)) is IMediator mediator)
-        {
             await mediator.Send(new ValidateAllSubscriptionsCommand());
+
+            Log.Information("It's alive !");
+        }
+        catch (Exception e)
+        {
+            Log.Fatal(e, "It died !");
+            lifetime.StopApplication();
         }
     }
 
@@ -160,12 +176,11 @@ private static WebApplicationBuilder ConfigureWebHost(string[] args, IConfigurat
         builder.Host.ConfigureServices(services =>
         {
             services.AddSimulatorSettings(configuration);
-
             services.AddMediatR(Assembly.GetExecutingAssembly());
             services.AddHttpClient();
 
             services.AddScoped<SasKeyValidator>();
-            services.AddSingleton<ValidationIpAddress>();
+            services.AddSingleton<ValidationIpAddressProvider>();
 
             services.AddControllers(options => { options.EnableEndpointRouting = false; })
                     .AddJsonOptions(options => { options.JsonSerializerOptions.WriteIndented = true; });