Allow changing the severity of resilience events

src/Polly.Extensions/PublicAPI.Unshipped.txt

@@ -1,4 +1,7 @@
 #nullable enable
+Polly.Telemetry.TelemetryOptions.SeverityProvider.get -> System.Func<Polly.Telemetry.ResilienceEvent, Polly.Telemetry.ResilienceEventSeverity>?
+Polly.Telemetry.TelemetryOptions.SeverityProvider.set -> void
+Polly.Telemetry.TelemetryOptions.TelemetryOptions(Polly.Telemetry.TelemetryOptions! other) -> void
 static Polly.PollyServiceCollectionExtensions.AddResiliencePipelines<TKey>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services, System.Action<Polly.DependencyInjection.AddResiliencePipelinesContext<TKey>!>! configure) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 Polly.DependencyInjection.AddResiliencePipelinesContext<TKey>
 Polly.DependencyInjection.AddResiliencePipelinesContext<TKey>.AddResiliencePipeline(TKey key, System.Action<Polly.ResiliencePipelineBuilder!, Polly.DependencyInjection.AddResiliencePipelineContext<TKey>!>! configure) -> void

src/Polly.Extensions/Telemetry/TelemetryListenerImpl.cs

@@ -11,6 +11,7 @@ internal sealed class TelemetryListenerImpl : TelemetryListener
     private readonly ILogger _logger;
     private readonly Func<ResilienceContext, object?, object?> _resultFormatter;
     private readonly List<TelemetryListener> _listeners;
+    private readonly Func<ResilienceEvent, ResilienceEventSeverity>? _severityProvider;
     private readonly List<MeteringEnricher> _enrichers;
 
     public TelemetryListenerImpl(TelemetryOptions options)
@@ -19,6 +20,7 @@ public TelemetryListenerImpl(TelemetryOptions options)
         _logger = options.LoggerFactory.CreateLogger(TelemetryUtil.PollyDiagnosticSource);
         _resultFormatter = options.ResultFormatter;
         _listeners = options.TelemetryListeners.ToList();
+        _severityProvider = options.SeverityProvider;
 
         Counter = Meter.CreateCounter<int>(
             "resilience.polly.strategy.events",
@@ -52,8 +54,15 @@ public override void Write<TResult, TArgs>(in TelemetryEventArguments<TResult, T
             }
         }
 
-        LogEvent(in args);
-        MeterEvent(in args);
+        var severity = args.Event.Severity;
+
+        if (_severityProvider is { } provider)
+        {
+            severity = provider(args.Event);
+        }
+
+        LogEvent(in args, severity);
+        MeterEvent(in args, severity);
     }
 
     private static bool GetArgs<T, TArgs>(T inArgs, out TArgs outArgs)
@@ -68,13 +77,13 @@ private static bool GetArgs<T, TArgs>(T inArgs, out TArgs outArgs)
         return false;
     }
 
-    private static void AddCommonTags<TResult, TArgs>(in EnrichmentContext<TResult, TArgs> context)
+    private static void AddCommonTags<TResult, TArgs>(in EnrichmentContext<TResult, TArgs> context, ResilienceEventSeverity severity)
     {
         var source = context.TelemetryEvent.Source;
         var ev = context.TelemetryEvent.Event;
 
         context.Tags.Add(new(ResilienceTelemetryTags.EventName, context.TelemetryEvent.Event.EventName));
-        context.Tags.Add(new(ResilienceTelemetryTags.EventSeverity, context.TelemetryEvent.Event.Severity.AsString()));
+        context.Tags.Add(new(ResilienceTelemetryTags.EventSeverity, severity.AsString()));
 
         if (source.PipelineName is not null)
         {
@@ -102,7 +111,7 @@ private static void AddCommonTags<TResult, TArgs>(in EnrichmentContext<TResult,
         }
     }
 
-    private void MeterEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArgs> args)
+    private void MeterEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArgs> args, ResilienceEventSeverity severity)
     {
         var arguments = args.Arguments;
 
@@ -115,7 +124,7 @@ private void MeterEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArg
 
             var tags = TagsList.Get();
             var context = new EnrichmentContext<TResult, TArgs>(in args, tags.Tags);
-            UpdateEnrichmentContext(in context);
+            UpdateEnrichmentContext(in context, severity);
             ExecutionDuration.Record(executionFinished.Duration.TotalMilliseconds, tags.TagsSpan);
             TagsList.Return(tags);
         }
@@ -128,7 +137,7 @@ private void MeterEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArg
 
             var tags = TagsList.Get();
             var context = new EnrichmentContext<TResult, TArgs>(in args, tags.Tags);
-            UpdateEnrichmentContext(in context);
+            UpdateEnrichmentContext(in context, severity);
             context.Tags.Add(new(ResilienceTelemetryTags.AttemptNumber, executionAttempt.AttemptNumber.AsBoxedInt()));
             context.Tags.Add(new(ResilienceTelemetryTags.AttemptHandled, executionAttempt.Handled.AsBoxedBool()));
             AttemptDuration.Record(executionAttempt.Duration.TotalMilliseconds, tags.TagsSpan);
@@ -138,15 +147,15 @@ private void MeterEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArg
         {
             var tags = TagsList.Get();
             var context = new EnrichmentContext<TResult, TArgs>(in args, tags.Tags);
-            UpdateEnrichmentContext(in context);
+            UpdateEnrichmentContext(in context, severity);
             Counter.Add(1, tags.TagsSpan);
             TagsList.Return(tags);
         }
     }
 
-    private void UpdateEnrichmentContext<TResult, TArgs>(in EnrichmentContext<TResult, TArgs> context)
+    private void UpdateEnrichmentContext<TResult, TArgs>(in EnrichmentContext<TResult, TArgs> context, ResilienceEventSeverity severity)
     {
-        AddCommonTags(in context);
+        AddCommonTags(in context, severity);
 
         if (_enrichers.Count != 0)
         {
@@ -157,10 +166,10 @@ private void UpdateEnrichmentContext<TResult, TArgs>(in EnrichmentContext<TResul
         }
     }
 
-    private void LogEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArgs> args)
+    private void LogEvent<TResult, TArgs>(in TelemetryEventArguments<TResult, TArgs> args, ResilienceEventSeverity severity)
     {
         var result = GetResult(args.Context, args.Outcome);
-        var level = args.Event.Severity.AsLogLevel();
+        var level = severity.AsLogLevel();
 
         if (GetArgs<TArgs, PipelineExecutingArguments>(args.Arguments, out _))
         {

src/Polly.Extensions/Telemetry/TelemetryOptions.cs

@@ -2,6 +2,7 @@
 using System.Net.Http;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
+using Polly.Utils;
 
 namespace Polly.Telemetry;
 
@@ -10,6 +11,28 @@ namespace Polly.Telemetry;
 /// </summary>
 public class TelemetryOptions
 {
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TelemetryOptions"/> class.
+    /// </summary>
+    public TelemetryOptions()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TelemetryOptions"/> class.
+    /// </summary>
+    /// <param name="other">The telemetry options instance to copy the data from.</param>
+    public TelemetryOptions(TelemetryOptions other)
+    {
+        Guard.NotNull(other);
+
+        TelemetryListeners = other.TelemetryListeners.ToList();
+        LoggerFactory = other.LoggerFactory;
+        MeteringEnrichers = other.MeteringEnrichers.ToList();
+        ResultFormatter = other.ResultFormatter;
+        SeverityProvider = other.SeverityProvider;
+    }
+
     /// <summary>
     /// Gets the collection of telemetry listeners.
     /// </summary>
@@ -48,4 +71,12 @@ public class TelemetryOptions
         HttpResponseMessage response => (int)response.StatusCode,
         _ => result,
     };
+
+    /// <summary>
+    /// Gets or sets the resilience event severity provider that allows customizing the severity of resilience events.
+    /// </summary>
+    /// <value>
+    /// The default value is <see langword="null"/>.
+    /// </value>
+    public Func<ResilienceEvent, ResilienceEventSeverity>? SeverityProvider { get; set; }
 }

src/Snippets/Docs/Telemetry.cs

@@ -134,4 +134,36 @@ public override void Enrich<TResult, TArgs>(in EnrichmentContext<TResult, TArgs>
     }
 
     #endregion
+
+    public static void SeverityOverrides()
+    {
+        var services = new ServiceCollection();
+
+        #region telemetry-severity-override
+
+        services.AddResiliencePipeline("my-strategy", (builder, context) =>
+        {
+            // Create a new instance of telemetry options by using copy-constructor of the global ones.
+            // This ensures that common configuration is preserved.
+            var telemetryOptions = new TelemetryOptions(context.GetOptions<TelemetryOptions>());
+
+            telemetryOptions.SeverityProvider = ev =>
+            {
+                if (ev.EventName == "OnRetry")
+                {
+                    // Decrease the severity of particular event.
+                    return ResilienceEventSeverity.Debug;
+                }
+
+                return ev.Severity;
+            };
+
+            builder.AddTimeout(TimeSpan.FromSeconds(1));
+
+            // Override the telemetry configuration for this pipeline.
+            builder.ConfigureTelemetry(telemetryOptions);
+        });
+
+        #endregion
+    }
 }