feat: error events (#135)

* feat: add errorevent mechanism * feat: implement errorevent in apiclient * feat: implement errorevents in fetchfeaturetogglestask * chore: more fetchtoggles task tests for IO * feat: implement errorevents in default unleash * feat: implement error events in cachedfilesloader * chore: eventconfig can be null * chore: docs + rename file * chore: test result, dont raise for impression evts * chore: add events handling to sample app
Unleash · May 22, 2023 · bc857fb · bc857fb
1 parent 81d8afb
commit bc857fb
Show file tree

Hide file tree

Showing 16 changed files with 330 additions and 32 deletions.
diff --git a/README.md b/README.md
@@ -171,6 +171,7 @@ Refer to the [Unleash context](#unleash-context) section for more information ab
 
 Currently supported events:
 - [Impression data events](https://docs.getunleash.io/advanced/impression-data#impression-event-data)
+- Error events
 
 ```csharp
 
@@ -181,10 +182,11 @@ var settings = new UnleashSettings()
 
 var unleash = new DefaultUnleash(settings);
 
-// Set up handling of impression events
+// Set up handling of impression and error events
 unleash.ConfigureEvents(cfg =>
 {
     cfg.ImpressionEvent = evt => { Console.WriteLine($"{evt.FeatureName}: {evt.Enabled}"); };
+    cfg.ErrorEvent = evt => { /* Handling code here */ Console.WriteLine($"{evt.ErrorType} occured."); };
 });
 
 ```

diff --git a/samples/WebApplication/Startup.cs b/samples/WebApplication/Startup.cs
@@ -22,14 +22,20 @@ public Startup(IConfiguration configuration)
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddControllers();
-            services.AddSingleton<IUnleash>(c => new DefaultUnleash(new UnleashSettings()
+            var unleash = new DefaultUnleash(new UnleashSettings()
             {
-                UnleashApi = new Uri("http://web:4242"),
+                UnleashApi = new Uri("http://localhost:4242/api"),
                 AppName = "variant-sample",
                 InstanceTag = "instance 1",
                 SendMetricsInterval = TimeSpan.FromSeconds(10),
                 FetchTogglesInterval = TimeSpan.FromSeconds(10),
-            }));
+            });
+            unleash.ConfigureEvents(evtCfg =>
+            {
+                evtCfg.ImpressionEvent = evt => { Console.WriteLine(evt.FeatureName); };
+                evtCfg.ErrorEvent = evt => { Console.WriteLine(evt.ErrorType + "-" + evt.Error?.Message); };
+            });
+            services.AddSingleton<IUnleash>(c => unleash);
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

diff --git a/src/Unleash/Communication/UnleashApiClient.cs b/src/Unleash/Communication/UnleashApiClient.cs
@@ -4,6 +4,7 @@
 using System.Net.Http.Headers;
 using System.Threading;
 using System.Threading.Tasks;
+using Unleash.Events;
 using Unleash.Internal;
 using Unleash.Logging;
 using Unleash.Metrics;
@@ -18,17 +19,20 @@ internal class UnleashApiClient : IUnleashApiClient
         private readonly HttpClient httpClient;
         private readonly IJsonSerializer jsonSerializer;
         private readonly UnleashApiClientRequestHeaders clientRequestHeaders;
+        private readonly EventCallbackConfig eventConfig;
         private readonly string projectId;
 
         public UnleashApiClient(
             HttpClient httpClient, 
             IJsonSerializer jsonSerializer, 
             UnleashApiClientRequestHeaders clientRequestHeaders,
+            EventCallbackConfig eventConfig,
             string projectId = null)
         {
             this.httpClient = httpClient;
             this.jsonSerializer = jsonSerializer;
             this.clientRequestHeaders = clientRequestHeaders;
+            this.eventConfig = eventConfig;
             this.projectId = projectId;
         }
 
@@ -51,6 +55,7 @@ public async Task<FetchTogglesResult> FetchToggles(string etag, CancellationToke
                     {
                         var error = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
                         Logger.Trace($"UNLEASH: Error {response.StatusCode} from server in '{nameof(FetchToggles)}': " + error);
+                        eventConfig?.RaiseError(new ErrorEvent() { ErrorType = ErrorType.Client, StatusCode = response.StatusCode, Resource = resourceUri });
 
                         return new FetchTogglesResult
                         {
@@ -139,6 +144,7 @@ private async Task<bool> Post(string resourceUri, Stream stream, CancellationTok
 
                     var error = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
                     Logger.Trace($"UNLEASH: Error {response.StatusCode} from request '{resourceUri}' in '{nameof(UnleashApiClient)}': " + error);
+                    eventConfig?.RaiseError(new ErrorEvent() { Resource = resourceUri, ErrorType = ErrorType.Client, StatusCode = response.StatusCode });
 
                     return false;
                 }

diff --git a/src/Unleash/DefaultUnleash.cs b/src/Unleash/DefaultUnleash.cs
@@ -7,6 +7,7 @@ namespace Unleash
     using System.Collections.Generic;
     using System.Linq;
     using System.Threading;
+    using Unleash.Events;
     using Unleash.Variants;
 
     /// <inheritdoc />
@@ -64,7 +65,7 @@ public DefaultUnleash(UnleashSettings settings, bool overrideDefaultStrategies,
             strategies = SelectStrategies(strategies, overrideDefaultStrategies);
             strategyMap = BuildStrategyMap(strategies);
 
-            services = new UnleashServices(settings, strategyMap);
+            services = new UnleashServices(settings, EventConfig, strategyMap);
 
             Logger.Info($"UNLEASH: Unleash instance number { currentInstanceNo } is initialized and configured with: {settings}");
 
@@ -78,7 +79,7 @@ public DefaultUnleash(UnleashSettings settings, bool overrideDefaultStrategies,
         /// <inheritdoc />
         public ICollection<FeatureToggle> FeatureToggles => services.ToggleCollection.Instance.Features;
 
-        private EventCallbackConfig EventConfig { get; set; }
+        private EventCallbackConfig EventConfig { get; } = new EventCallbackConfig();
 
         /// <inheritdoc />
         public bool IsEnabled(string toggleName)
@@ -253,9 +254,7 @@ public void ConfigureEvents(Action<EventCallbackConfig> callback)
 
             try
             {
-                var evtConfig = new EventCallbackConfig();
-                callback(evtConfig);
-                EventConfig = evtConfig;
+                callback(EventConfig);
             }
             catch (Exception ex)
             {

diff --git a/src/Unleash/Events/ErrorEvent.cs b/src/Unleash/Events/ErrorEvent.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Text;
+
+namespace Unleash.Events
+{
+    public class ErrorEvent
+    {
+        public ErrorType ErrorType { get; set; }
+        public Exception Error { get; set; }
+        public HttpStatusCode? StatusCode { get; internal set; }
+        public string Resource { get; internal set; }
+    }
+}
diff --git a/src/Unleash/Events/ErrorType.cs b/src/Unleash/Events/ErrorType.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Unleash.Events
+{
+    public enum ErrorType
+    {
+        Client,
+        TogglesBackup,
+        Bootstrap,
+        ImpressionEvent,
+        FileCache
+    }
+}
diff --git a/src/Unleash/Internal/CachedFilesLoader.cs b/src/Unleash/Internal/CachedFilesLoader.cs
@@ -1,4 +1,5 @@
 using System.IO;
+using Unleash.Events;
 using Unleash.Logging;
 using Unleash.Scheduling;
 using Unleash.Serialization;
@@ -11,15 +12,24 @@ internal class CachedFilesLoader
         private readonly IJsonSerializer jsonSerializer;
         private readonly IFileSystem fileSystem;
         private readonly IToggleBootstrapProvider toggleBootstrapProvider;
+        private readonly EventCallbackConfig eventConfig;
         private readonly string toggleFile;
         private readonly string etagFile;
         private readonly bool bootstrapOverride;
 
-        public CachedFilesLoader(IJsonSerializer jsonSerializer, IFileSystem fileSystem, IToggleBootstrapProvider toggleBootstrapProvider, string toggleFile, string etagFile, bool bootstrapOverride = true)
+        public CachedFilesLoader(
+            IJsonSerializer jsonSerializer,
+            IFileSystem fileSystem,
+            IToggleBootstrapProvider toggleBootstrapProvider,
+            EventCallbackConfig eventConfig,
+            string toggleFile,
+            string etagFile,
+            bool bootstrapOverride = true)
         {
             this.jsonSerializer = jsonSerializer;
             this.fileSystem = fileSystem;
             this.toggleBootstrapProvider = toggleBootstrapProvider;
+            this.eventConfig = eventConfig;
             this.toggleFile = toggleFile;
             this.etagFile = etagFile;
             this.bootstrapOverride = bootstrapOverride;
@@ -40,6 +50,7 @@ public CachedFilesResult EnsureExistsAndLoad()
                 catch (IOException ex)
                 {
                     Logger.ErrorException($"UNLEASH: Unhandled exception when writing to ETag file '{etagFile}'.", ex);
+                    eventConfig?.RaiseError(new ErrorEvent() { Error = ex, ErrorType = ErrorType.FileCache });
                 }
             }
             else
@@ -51,6 +62,7 @@ public CachedFilesResult EnsureExistsAndLoad()
                 catch (IOException ex)
                 {
                     Logger.ErrorException($"UNLEASH: Unhandled exception when reading from ETag file '{etagFile}'.", ex);
+                    eventConfig?.RaiseError(new ErrorEvent() { Error = ex, ErrorType = ErrorType.FileCache });
                 }
             }
 
@@ -65,6 +77,7 @@ public CachedFilesResult EnsureExistsAndLoad()
                 catch (IOException ex)
                 {
                     Logger.ErrorException($"UNLEASH: Unhandled exception when writing to toggle file '{toggleFile}'.", ex);
+                    eventConfig?.RaiseError(new ErrorEvent() { Error = ex, ErrorType = ErrorType.FileCache });
                 }
             }
             else
@@ -79,6 +92,7 @@ public CachedFilesResult EnsureExistsAndLoad()
                 catch (IOException ex)
                 {
                     Logger.ErrorException($"UNLEASH: Unhandled exception when reading from toggle file '{toggleFile}'.", ex);
+                    eventConfig?.RaiseError(new ErrorEvent() { Error = ex, ErrorType = ErrorType.FileCache });
                 }
             }
 

diff --git a/src/Unleash/Internal/EventCallbackConfig.cs b/src/Unleash/Internal/EventCallbackConfig.cs
@@ -1,11 +1,19 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
+using Unleash.Events;
 
 namespace Unleash.Internal
 {
     public class EventCallbackConfig
     {
         public Action<ImpressionEvent> ImpressionEvent { get; set; }
+        public Action<ErrorEvent> ErrorEvent { get; set; }
+
+        public void RaiseError(ErrorEvent evt)
+        {
+            if (ErrorEvent != null)
+            {
+                ErrorEvent(evt);
+            }
+        }
     }
 }
diff --git a/src/Unleash/Internal/UnleashServices.cs b/src/Unleash/Internal/UnleashServices.cs
@@ -25,7 +25,7 @@ internal class UnleashServices : IDisposable
         internal ThreadSafeMetricsBucket MetricsBucket { get; }
         internal FetchFeatureTogglesTask FetchFeatureTogglesTask { get; }
 
-        public UnleashServices(UnleashSettings settings, Dictionary<string, IStrategy> strategyMap)
+        public UnleashServices(UnleashSettings settings, EventCallbackConfig eventConfig, Dictionary<string, IStrategy> strategyMap)
         {
             var fileSystem = settings.FileSystem ?? new FileSystem(settings.Encoding);
 
@@ -36,7 +36,7 @@ public UnleashServices(UnleashSettings settings, Dictionary<string, IStrategy> s
             CancellationToken = cancellationTokenSource.Token;
             ContextProvider = settings.UnleashContextProvider;
 
-            var loader = new CachedFilesLoader(settings.JsonSerializer, fileSystem, settings.ToggleBootstrapProvider, backupFile, etagBackupFile, settings.BootstrapOverride);
+            var loader = new CachedFilesLoader(settings.JsonSerializer, fileSystem, settings.ToggleBootstrapProvider, eventConfig, backupFile, etagBackupFile, settings.BootstrapOverride);
             var cachedFilesResult = loader.EnsureExistsAndLoad();
 
             ToggleCollection = new ThreadSafeToggleCollection
@@ -63,7 +63,7 @@ public UnleashServices(UnleashSettings settings, Dictionary<string, IStrategy> s
                     CustomHttpHeaders = settings.CustomHttpHeaders,
                     CustomHttpHeaderProvider = settings.UnleashCustomHttpHeaderProvider,
                     SupportedSpecVersion = supportedSpecVersion
-                }, settings.ProjectId);
+                }, eventConfig, settings.ProjectId);
             }
             else
             {
@@ -77,9 +77,10 @@ public UnleashServices(UnleashSettings settings, Dictionary<string, IStrategy> s
 
             var fetchFeatureTogglesTask = new FetchFeatureTogglesTask(
                 apiClient, 
-                ToggleCollection, 
+                ToggleCollection,
                 settings.JsonSerializer, 
-                fileSystem, 
+                fileSystem,
+                eventConfig,
                 backupFile, 
                 etagBackupFile)
             {

diff --git a/src/Unleash/Scheduling/FetchFeatureTogglesTask.cs b/src/Unleash/Scheduling/FetchFeatureTogglesTask.cs
@@ -6,6 +6,8 @@
 using Unleash.Internal;
 using Unleash.Serialization;
 using Unleash.Logging;
+using Unleash.Events;
+using System.Net.Http;
 
 namespace Unleash.Scheduling
 {
@@ -16,6 +18,7 @@ internal class FetchFeatureTogglesTask : IUnleashScheduledTask
         private readonly string etagFile;
 
         private readonly IFileSystem fileSystem;
+        private readonly EventCallbackConfig eventConfig;
         private readonly IUnleashApiClient apiClient;
         private readonly IJsonSerializer jsonSerializer;
         private readonly ThreadSafeToggleCollection toggleCollection;
@@ -28,20 +31,32 @@ public FetchFeatureTogglesTask(
             ThreadSafeToggleCollection toggleCollection,
             IJsonSerializer jsonSerializer,
             IFileSystem fileSystem,
+            EventCallbackConfig eventConfig,
             string toggleFile,
             string etagFile)
         {
             this.apiClient = apiClient;
             this.toggleCollection = toggleCollection;
             this.jsonSerializer = jsonSerializer;
             this.fileSystem = fileSystem;
+            this.eventConfig = eventConfig;
             this.toggleFile = toggleFile;
             this.etagFile = etagFile;
         }
 
         public async Task ExecuteAsync(CancellationToken cancellationToken)
         {
-            var result = await apiClient.FetchToggles(Etag, cancellationToken).ConfigureAwait(false);
+            FetchTogglesResult result;
+            try
+            {
+                result = await apiClient.FetchToggles(Etag, cancellationToken).ConfigureAwait(false);
+            }
+            catch (HttpRequestException ex)
+            {
+                Logger.ErrorException($"UNLEASH: Unhandled exception when fetching toggles.", ex);
+                eventConfig?.RaiseError(new ErrorEvent() { ErrorType = ErrorType.Client, Error = ex });
+                return;
+            }
 
             if (!result.HasChanged)
                 return;
@@ -64,6 +79,7 @@ public async Task ExecuteAsync(CancellationToken cancellationToken)
             catch (IOException ex)
             {
                 Logger.ErrorException($"UNLEASH: Unhandled exception when writing to toggle file '{toggleFile}'.", ex);
+                eventConfig?.RaiseError(new ErrorEvent() { ErrorType = ErrorType.TogglesBackup, Error = ex });
             }
 
             Etag = result.Etag;
@@ -75,6 +91,7 @@ public async Task ExecuteAsync(CancellationToken cancellationToken)
             catch (IOException ex)
             {
                 Logger.ErrorException($"UNLEASH: Unhandled exception when writing to ETag file '{etagFile}'.", ex);
+                eventConfig?.RaiseError(new ErrorEvent() { ErrorType = ErrorType.TogglesBackup, Error = ex });
             }
         }
 

diff --git a/tests/Unleash.Tests/Communication/BaseUnleashApiClientTest.cs b/tests/Unleash.Tests/Communication/BaseUnleashApiClientTest.cs
@@ -4,6 +4,8 @@
 using NUnit.Framework;
 using NUnit.Framework.Internal;
 using Unleash.Communication;
+using Unleash.Events;
+using Unleash.Internal;
 using Unleash.Serialization;
 
 namespace Unleash.Tests.Communication
@@ -32,7 +34,7 @@ private static IUnleashApiClient CreateApiClient()
             };
 
             var httpClient = httpClientFactory.Create(apiUri);
-            var client = new UnleashApiClient(httpClient, jsonSerializer, requestHeaders);
+            var client = new UnleashApiClient(httpClient, jsonSerializer, requestHeaders, new EventCallbackConfig());
             return client;
         }
 

diff --git a/tests/Unleash.Tests/Communication/UnleashApiClient_Project_Tests.cs b/tests/Unleash.Tests/Communication/UnleashApiClient_Project_Tests.cs
@@ -8,6 +8,8 @@
 using FluentAssertions;
 using NUnit.Framework;
 using Unleash.Communication;
+using Unleash.Events;
+using Unleash.Internal;
 using Unleash.Serialization;
 using Unleash.Tests.Mock;
 
@@ -36,7 +38,7 @@ private UnleashApiClient NewTestableClient(string project, MockHttpMessageHandle
                 Timeout = TimeSpan.FromSeconds(5)
             };
 
-            return new UnleashApiClient(httpClient, jsonSerializer, requestHeaders, project);
+            return new UnleashApiClient(httpClient, jsonSerializer, requestHeaders, new EventCallbackConfig(), project);
         }
 
         [Test]