From 224a5e5ff526f33627bc6a8c5c00a6bdccf74309 Mon Sep 17 00:00:00 2001
From: kjuulh <contact@kjuulh.io>
Date: Sun, 14 Nov 2021 22:32:49 +0100
Subject: [PATCH] Add health check

---
 src/backend/server/src/Todo.Api/Startup.cs    | 43 +++++++++++++++++--
 .../Todo.Persistence/DependencyInjection.cs   | 11 +++--
 .../Mongo/MongoDbConnectionHandler.cs         |  6 ++-
 .../Todo.Persistence/Todo.Persistence.csproj  |  1 +
 4 files changed, 52 insertions(+), 9 deletions(-)

diff --git a/src/backend/server/src/Todo.Api/Startup.cs b/src/backend/server/src/Todo.Api/Startup.cs
index 37a8ebb..200e6fe 100644
--- a/src/backend/server/src/Todo.Api/Startup.cs
+++ b/src/backend/server/src/Todo.Api/Startup.cs
@@ -1,5 +1,7 @@
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics.HealthChecks;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -37,7 +39,10 @@ namespace Todo.Api
                 c.SwaggerDoc("v1", new OpenApiInfo { Title = "Todo.Api", Version = "v1" });
             });
 
-            services.AddPersistence(Configuration);
+            services.AddPersistence(Configuration, out var mongoDbOptions);
+            services
+                .AddHealthChecks()
+                .AddMongoDb(MongoDbConnectionHandler.FormatConnectionString(mongoDbOptions));
             services.AddSignalR();
         }
 
@@ -45,7 +50,7 @@ namespace Todo.Api
         public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
         {
             app.MigrateMongoDb();
-            
+
             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();
@@ -62,7 +67,39 @@ namespace Todo.Api
             {
                 endpoints.MapControllers();
                 endpoints.MapHub<TodoHub>("/hubs/todo");
+                endpoints.MapHealthChecks("/health/live", new HealthCheckOptions()
+                {
+                    ResponseWriter = async (context, report) =>
+                    {
+                        var response = new HealthCheckResponse()
+                        {
+                            Status = report.Status.ToString(),
+                            HealthChecks = report.Entries.Select(x => new IndividualHealthCheckResponse
+                            {
+                                Component = x.Key,
+                                Status = x.Value.Status.ToString(),
+                                Description = x.Value.Description
+                            }),
+                            HealthCheckDuration = report.TotalDuration
+                        };
+                        await context.Response.WriteAsJsonAsync(response);
+                    }
+                });
             });
         }
+
+        private class HealthCheckResponse
+        {
+            public string Status { get; set; }
+            public IEnumerable<IndividualHealthCheckResponse> HealthChecks { get; set; }
+            public TimeSpan HealthCheckDuration { get; set; }
+        }
+
+        private class IndividualHealthCheckResponse
+        {
+            public string Status { get; set; }
+            public string Component { get; set; }
+            public string Description { get; set; }
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/src/backend/server/src/Todo.Persistence/DependencyInjection.cs b/src/backend/server/src/Todo.Persistence/DependencyInjection.cs
index 154cdbf..29aa794 100644
--- a/src/backend/server/src/Todo.Persistence/DependencyInjection.cs
+++ b/src/backend/server/src/Todo.Persistence/DependencyInjection.cs
@@ -4,6 +4,7 @@ global using System.Linq;
 global using System.Collections.Generic;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Todo.Core.Interfaces.Persistence;
 using Todo.Persistence.Mongo;
 using Todo.Persistence.Mongo.Repositories;
@@ -12,12 +13,14 @@ namespace Todo.Persistence
 {
     public static class DependencyInjection
     {
-        public static IServiceCollection AddPersistence(this IServiceCollection services, IConfiguration configuration)
+        public static IServiceCollection AddPersistence(this IServiceCollection services, IConfiguration configuration,
+            out MongoDbOptions mongoDbOptions)
         {
-            
+            var exportableMongoDbOptions = new MongoDbOptions();
             var options = configuration.GetRequiredSection("MONGODB");
-            Console.WriteLine(options.Value);
-            
+            options.Bind(exportableMongoDbOptions);
+            mongoDbOptions = exportableMongoDbOptions;
+
             services
                 .AddOptions<MongoDbOptions>()
                 .Bind(options)
diff --git a/src/backend/server/src/Todo.Persistence/Mongo/MongoDbConnectionHandler.cs b/src/backend/server/src/Todo.Persistence/Mongo/MongoDbConnectionHandler.cs
index 1f39b12..d85f230 100644
--- a/src/backend/server/src/Todo.Persistence/Mongo/MongoDbConnectionHandler.cs
+++ b/src/backend/server/src/Todo.Persistence/Mongo/MongoDbConnectionHandler.cs
@@ -21,10 +21,12 @@ public class MongoDbConnectionHandler
 
     private static IMongoDatabase CreateConnectionFromOptions(MongoDbOptions options)
     {
-        var conn = new MongoClient(
-            $"mongodb://{options.Username}:{options.Password}@{options.Host}:{options.Port}");
+        var conn = new MongoClient(FormatConnectionString(options));
         var database = conn.GetDatabase(options.Database);
 
         return database;
     }
+
+    public static string FormatConnectionString(MongoDbOptions options) =>
+        $"mongodb://{options.Username}:{options.Password}@{options.Host}:{options.Port}";
 }
\ No newline at end of file
diff --git a/src/backend/server/src/Todo.Persistence/Todo.Persistence.csproj b/src/backend/server/src/Todo.Persistence/Todo.Persistence.csproj
index 3b14b3d..358426b 100644
--- a/src/backend/server/src/Todo.Persistence/Todo.Persistence.csproj
+++ b/src/backend/server/src/Todo.Persistence/Todo.Persistence.csproj
@@ -11,6 +11,7 @@
     <ItemGroup>
         <PackageReference Include="MongoDB.Driver" Version="2.13.2" />
         <PackageReference Include="MongoDB.Driver.Core" Version="2.13.2" />
+        <PackageReference Include="AspNetCore.HealthChecks.MongoDb" Version="5.0.1" />
     </ItemGroup>
 
     <ItemGroup>