Add Blob Storage to Health Check

BuildingBlocks/src/BuildingBlocks.Infrastructure/BuildingBlocks.Infrastructure.csproj

@@ -19,6 +19,7 @@
         <PackageReference Include="RabbitMQ.Client" Version="6.8.1" />
         <PackageReference Include="Serilog" Version="4.0.2" />
         <PackageReference Include="System.Interactive.Async" Version="6.0.1" />
+        <PackageReference Include="AspNetCore.HealthChecks.Azure.Storage.Blobs" Version="8.0.1" />
     </ItemGroup>
 
     <ItemGroup>

BuildingBlocks/src/BuildingBlocks.Infrastructure/Persistence/BlobStorage/BlobStorageHealthCheck.cs

@@ -0,0 +1,82 @@
+using System.Text;
+using Backbone.BuildingBlocks.Application.Abstractions.Infrastructure.Persistence.BlobStorage;
+using Backbone.Tooling.Extensions;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+
+namespace Backbone.BuildingBlocks.Infrastructure.Persistence.BlobStorage;
+
+public class BlobStorageHealthCheck : IHealthCheck
+{
+    private const string FILE_TEXT = "healthcheck";
+    private const int MAX_NUMBER_OF_TRIES = 5;
+
+    private static bool? _isHealthy;
+    private static int _numberOfTries = 0;
+
+    private readonly IBlobStorage _storage;
+    private readonly string _bucketName;
+
+    public BlobStorageHealthCheck(IBlobStorage storage, string bucketName)
+    {
+        _storage = storage;
+        _bucketName = bucketName;
+    }
+
+    public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
+    {
+        if (!_isHealthy.HasValue || (_isHealthy == false && _numberOfTries < MAX_NUMBER_OF_TRIES))
+        {
+            var filename = Guid.NewGuid().ToString();
+            var isUploadPossible = await IsUploadPossible(filename);
+            var isDownloadPossible = await IsDownloadPossible(filename);
+            var isDeletionPossible = await IsDeletionPossible(filename);
+
+            _isHealthy = isUploadPossible && isDownloadPossible && isDeletionPossible;
+            _numberOfTries++;
+        }
+
+        return _isHealthy.Value ? HealthCheckResult.Healthy() : HealthCheckResult.Unhealthy();
+    }
+
+    private async Task<bool> IsUploadPossible(string filename)
+    {
+        try
+        {
+            _storage.Add(_bucketName, filename, FILE_TEXT.GetBytes());
+            await _storage.SaveAsync();
+            return true;
+        }
+        catch (Exception)
+        {
+            return false;
+        }
+    }
+
+    private async Task<bool> IsDownloadPossible(string filename)
+    {
+        try
+        {
+            var downloadBytes = await _storage.FindAsync(_bucketName, filename);
+            var downloadedString = Encoding.UTF8.GetString(downloadBytes);
+            return downloadedString == FILE_TEXT;
+        }
+        catch (Exception)
+        {
+            return false;
+        }
+    }
+
+    private async Task<bool> IsDeletionPossible(string filename)
+    {
+        try
+        {
+            _storage.Remove(_bucketName, filename);
+            await _storage.SaveAsync();
+            return true;
+        }
+        catch (Exception)
+        {
+            return false;
+        }
+    }
+}

BuildingBlocks/src/BuildingBlocks.Infrastructure/Persistence/BlobStorage/BlobStorageServiceCollectionExtensions.cs

@@ -1,7 +1,9 @@
+using Backbone.BuildingBlocks.Application.Abstractions.Infrastructure.Persistence.BlobStorage;
 using Backbone.BuildingBlocks.Infrastructure.Persistence.BlobStorage.AzureStorageAccount;
 using Backbone.BuildingBlocks.Infrastructure.Persistence.BlobStorage.GoogleCloudStorage;
 using Backbone.Tooling.Extensions;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
 
 namespace Backbone.BuildingBlocks.Infrastructure.Persistence.BlobStorage;
 
@@ -41,6 +43,14 @@ public static void AddBlobStorage(this IServiceCollection services, BlobStorageO
                     $"{options.CloudProvider} is not a currently supported cloud provider.");
             }
         }
+
+        services.AddHealthChecks().Add(
+            new HealthCheckRegistration(
+                "blob_storage",
+                sp => new BlobStorageHealthCheck(sp.GetRequiredService<IBlobStorage>(), options.Container),
+                HealthStatus.Unhealthy, null
+            )
+        );
     }
 }