Added HealthCheck (#188)

Checks home page.

src/Web/HealthChecks/HomePageHealthCheck.cs

@@ -0,0 +1,34 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.eShopWeb.Web.HealthChecks
+{
+    public class HomePageHealthCheck : IHealthCheck
+    {
+        private readonly IHttpContextAccessor _httpContextAccessor;
+
+        public HomePageHealthCheck(IHttpContextAccessor httpContextAccessor)
+        {
+            _httpContextAccessor = httpContextAccessor;
+        }
+
+        public async Task<HealthCheckResult> CheckHealthAsync(
+            HealthCheckContext context,
+            CancellationToken cancellationToken = default(CancellationToken))
+        {
+            string myUrl = _httpContextAccessor.HttpContext.Request.Host.ToString();
+            var client = new HttpClient();
+            var response = await client.GetAsync(myUrl);
+            var pageContents = await response.Content.ReadAsStringAsync();
+            if (pageContents.Contains(".NET Bot Black Sweatshirt"))
+            {
+                return HealthCheckResult.Healthy("The check indicates a healthy result.");
+            }
+
+            return HealthCheckResult.Unhealthy("The check indicates an unhealthy result.");
+        }
+    }
+}

src/Web/Startup.cs

@@ -13,6 +13,7 @@ using Microsoft.eShopWeb.Infrastructure.Data;
 using Microsoft.eShopWeb.Infrastructure.Identity;
 using Microsoft.eShopWeb.Infrastructure.Logging;
 using Microsoft.eShopWeb.Infrastructure.Services;
+using Microsoft.eShopWeb.Web.HealthChecks;
 using Microsoft.eShopWeb.Web.Interfaces;
 using Microsoft.eShopWeb.Web.Services;
 using Microsoft.Extensions.Configuration;
@@ -113,13 +114,15 @@ namespace Microsoft.eShopWeb.Web
                          new SlugifyParameterTransformer()));
             }
             ).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
-
+            services.AddHttpContextAccessor();
-
-
             services.AddSwaggerGen(c =>
             {
                 c.SwaggerDoc("v1", new Info { Title = "My API", Version = "v1" });
             });
+
+            services.AddHealthChecks()
+                .AddCheck<HomePageHealthCheck>("home_page_health_check");
+
             _services = services; // used to debug registered services
         }
 
@@ -147,6 +150,8 @@ namespace Microsoft.eShopWeb.Web
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
         public void Configure(IApplicationBuilder app, IHostingEnvironment env, LinkGenerator linkGenerator)
         {
+            //app.UseDeveloperExceptionPage();
+            app.UseHealthChecks("/health");
             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();