improve check and set host ShutdownTimeout

Author: cwe1ss

ShuttingDownHealthCheck.cs

@@ -3,19 +3,41 @@
 using System.Threading.Tasks;
 using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
 
 namespace blog_zero_downtime_with_health_checks
 {
     public class ShuttingDownHealthCheck : IHealthCheck
     {
+        private readonly IHostEnvironment _hostEnvironment;
+        private readonly ILogger<ShuttingDownHealthCheck> _logger;
+
         private HealthStatus _status = HealthStatus.Healthy;
 
-        public ShuttingDownHealthCheck(IHostApplicationLifetime appLifetime)
+        public ShuttingDownHealthCheck(
+            IHostApplicationLifetime appLifetime,
+            IHostEnvironment hostEnvironment,
+            ILogger<ShuttingDownHealthCheck> logger)
         {
+            _hostEnvironment = hostEnvironment;
+            _logger = logger;
+
             appLifetime.ApplicationStopping.Register(() =>
             {
-                Console.WriteLine("Shutting down");
                 _status = HealthStatus.Unhealthy;
+
+                // We don't need to block on developer machines as there's no load balancers involved there.
+                bool delayShutdown = _hostEnvironment.IsProduction();
+                if (delayShutdown)
+                {
+                    var shutdownDelay = TimeSpan.FromSeconds(25);
+                    _logger.LogInformation("Delaying shutdown for {Seconds} seconds", shutdownDelay.TotalSeconds);
+
+                    // ASP.NET Core requests are processed on separate threads, so we can just put the main thread on sleep.
+                    Thread.Sleep(shutdownDelay);
+
+                    _logger.LogInformation("Shutdown delay completed");
+                }
             });
         }
 

Startup.cs

@@ -16,6 +16,11 @@ public class Startup
         // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
         public void ConfigureServices(IServiceCollection services)
         {
+            services.Configure<HostOptions>(option =>
+            {
+                option.ShutdownTimeout = System.TimeSpan.FromSeconds(30);
+            });
+
             services.AddSingleton<ShuttingDownHealthCheck>();
 
             services.AddHealthChecks()