Introduce ResilienceStrategyBuilder.InstanceName and use it in telemetry

src/Polly.Core/Registry/ConfigureBuilderContext.cs

@@ -9,11 +9,11 @@ namespace Polly.Registry;
 public class ConfigureBuilderContext<TKey>
     where TKey : notnull
 {
-    internal ConfigureBuilderContext(TKey strategyKey, string builderName, string strategyKeyString)
+    internal ConfigureBuilderContext(TKey strategyKey, string builderName, string? builderInstanceName)
     {
         StrategyKey = strategyKey;
         BuilderName = builderName;
-        StrategyKeyString = strategyKeyString;
+        BuilderInstanceName = builderInstanceName;
     }
 
     /// <summary>
@@ -27,9 +27,9 @@ internal ConfigureBuilderContext(TKey strategyKey, string builderName, string st
     public string BuilderName { get; }
 
     /// <summary>
-    /// Gets the string representation of strategy key for the strategy being created.
+    /// Gets the instance name for the builder being used to create the strategy.
     /// </summary>
-    public string StrategyKeyString { get; }
+    public string? BuilderInstanceName { get; }
 
     internal Func<Func<CancellationToken>>? ReloadTokenProducer { get; private set; }
 

src/Polly.Core/Registry/ResilienceStrategyRegistry.TResult.cs

@@ -11,21 +11,21 @@ private sealed class GenericRegistry<TResult>
         private readonly ConcurrentDictionary<TKey, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>>> _builders;
         private readonly ConcurrentDictionary<TKey, ResilienceStrategy<TResult>> _strategies;
 
-        private readonly Func<TKey, string> _strategyKeyFormatter;
         private readonly Func<TKey, string> _builderNameFormatter;
+        private readonly Func<TKey, string>? _instanceNameFormatter;
 
         public GenericRegistry(
             Func<ResilienceStrategyBuilder<TResult>> activator,
             IEqualityComparer<TKey> builderComparer,
             IEqualityComparer<TKey> strategyComparer,
-            Func<TKey, string> strategyKeyFormatter,
-            Func<TKey, string> builderNameFormatter)
+            Func<TKey, string> builderNameFormatter,
+            Func<TKey, string>? instanceNameFormatter)
         {
             _activator = activator;
             _builders = new ConcurrentDictionary<TKey, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>>>(builderComparer);
             _strategies = new ConcurrentDictionary<TKey, ResilienceStrategy<TResult>>(strategyComparer);
-            _strategyKeyFormatter = strategyKeyFormatter;
             _builderNameFormatter = builderNameFormatter;
+            _instanceNameFormatter = instanceNameFormatter;
         }
 
         public bool TryAdd(TKey key, ResilienceStrategy<TResult> strategy) => _strategies.TryAdd(key, strategy);
@@ -51,7 +51,7 @@ public bool TryGet(TKey key, [NotNullWhen(true)] out ResilienceStrategy<TResult>
 
         public ResilienceStrategy<TResult> GetOrAdd(TKey key, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>> configure)
         {
-            var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
+            var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _instanceNameFormatter?.Invoke(key));
 
 #if NETCOREAPP3_0_OR_GREATER
             return _strategies.GetOrAdd(key, static (_, factory) =>

src/Polly.Core/Registry/ResilienceStrategyRegistry.cs

@@ -24,7 +24,7 @@ public sealed partial class ResilienceStrategyRegistry<TKey> : ResilienceStrateg
     private readonly ConcurrentDictionary<TKey, ResilienceStrategy> _strategies;
     private readonly ConcurrentDictionary<Type, object> _genericRegistry = new();
 
-    private readonly Func<TKey, string> _strategyKeyFormatter;
+    private readonly Func<TKey, string>? _instanceNameFormatter;
     private readonly Func<TKey, string> _builderNameFormatter;
     private readonly IEqualityComparer<TKey> _builderComparer;
     private readonly IEqualityComparer<TKey> _strategyComparer;
@@ -52,7 +52,7 @@ public ResilienceStrategyRegistry(ResilienceStrategyRegistryOptions<TKey> option
         _activator = options.BuilderFactory;
         _builders = new ConcurrentDictionary<TKey, Action<ResilienceStrategyBuilder, ConfigureBuilderContext<TKey>>>(options.BuilderComparer);
         _strategies = new ConcurrentDictionary<TKey, ResilienceStrategy>(options.StrategyComparer);
-        _strategyKeyFormatter = options.StrategyKeyFormatter;
+        _instanceNameFormatter = options.InstanceNameFormatter;
         _builderNameFormatter = options.BuilderNameFormatter;
         _builderComparer = options.BuilderComparer;
         _strategyComparer = options.StrategyComparer;
@@ -154,7 +154,7 @@ public ResilienceStrategy GetOrAddStrategy(TKey key, Action<ResilienceStrategyBu
             return strategy;
         }
 
-        var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
+        var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _instanceNameFormatter?.Invoke(key));
 
 #if NETCOREAPP3_0_OR_GREATER
         return _strategies.GetOrAdd(key, static (_, factory) =>
@@ -272,7 +272,7 @@ private static ResilienceStrategy CreateStrategy<TBuilder>(
         {
             var builder = activator();
             builder.BuilderName = context.BuilderName;
-            builder.Properties.Set(TelemetryUtil.StrategyKey, context.StrategyKeyString);
+            builder.InstanceName = context.BuilderInstanceName;
             configure(builder, context);
 
             return builder;
@@ -294,6 +294,7 @@ private static ResilienceStrategy CreateStrategy<TBuilder>(
             TelemetryUtil.CreateTelemetry(
                 diagnosticSource,
                 context.BuilderName,
+                context.BuilderInstanceName,
                 builder.Properties,
                 ReloadableResilienceStrategy.StrategyName,
                 ReloadableResilienceStrategy.StrategyType));
@@ -312,8 +313,8 @@ private GenericRegistry<TResult> GetGenericRegistry<TResult>()
                 () => new ResilienceStrategyBuilder<TResult>(_activator()),
                 _builderComparer,
                 _strategyComparer,
-                _strategyKeyFormatter,
-                _builderNameFormatter);
+                _builderNameFormatter,
+                _instanceNameFormatter);
         });
     }
 }

src/Polly.Core/Registry/ResilienceStrategyRegistryOptions.cs

@@ -37,17 +37,16 @@ public class ResilienceStrategyRegistryOptions<TKey>
 
     /// <summary>
     /// Gets or sets the formatter that is used by the registry to format the <typeparamref name="TKey"/> to a string that
-    /// represents the strategy key.
+    /// represents the instance name of the builder.
     /// </summary>
     /// <remarks>
-    /// By default, the formatter uses the <see cref="object.ToString"/> method.
+    /// Defaults to <see langword="null"/>.
     /// <para>
-    /// Use custom formatter for composite keys in case you want to have different metric values for a builder and strategy key.
-    /// In general, strategies can have the same builder name and different strategy keys.
+    /// Use custom formatter for composite keys in case you want to have different metric values for a builder and instance key.
+    /// In general, strategies can have the same builder name and different instance names.
     /// </para>
     /// </remarks>
-    [Required]
-    public Func<TKey, string> StrategyKeyFormatter { get; set; } = (key) => key?.ToString() ?? string.Empty;
+    public Func<TKey, string>? InstanceNameFormatter { get; set; }
 
     /// <summary>
     /// Gets or sets the formatter that is used by the registry to format the <typeparamref name="TKey"/> to a string that

src/Polly.Core/ResilienceStrategyBuilderBase.cs

@@ -40,6 +40,16 @@ private protected ResilienceStrategyBuilderBase(ResilienceStrategyBuilderBase ot
     /// </remarks>
     public string? BuilderName { get; set; }
 
+    /// <summary>
+    /// Gets or sets the instance name of the builder.
+    /// </summary>
+    /// <remarks>
+    /// This property is also included in the telemetry that is produced by the individual resilience strategies.
+    /// The instance name can be used to differentiate between multiple builder instances with the same <see cref="BuilderName"/>.
+    /// Defaults to <see langword="null"/>.
+    /// </remarks>
+    public string? InstanceName { get; set; }
+
     /// <summary>
     /// Gets the custom properties attached to builder options.
     /// </summary>
@@ -125,6 +135,7 @@ private ResilienceStrategy CreateResilienceStrategy(Entry entry)
     {
         var context = new ResilienceStrategyBuilderContext(
             builderName: BuilderName,
+            builderInstanceName: InstanceName,
             builderProperties: Properties,
             strategyName: entry.Properties.StrategyName,
             strategyType: entry.Properties.StrategyType,

src/Polly.Core/ResilienceStrategyBuilderContext.cs

@@ -11,6 +11,7 @@ public sealed class ResilienceStrategyBuilderContext
 {
     internal ResilienceStrategyBuilderContext(
         string? builderName,
+        string? builderInstanceName,
         ResilienceProperties builderProperties,
         string? strategyName,
         string strategyType,
@@ -20,12 +21,13 @@ internal ResilienceStrategyBuilderContext(
         Func<double> randomizer)
     {
         BuilderName = builderName;
+        BuilderInstanceName = builderInstanceName;
         BuilderProperties = builderProperties;
         StrategyName = strategyName;
         StrategyType = strategyType;
         TimeProvider = timeProvider;
         IsGenericBuilder = isGenericBuilder;
-        Telemetry = TelemetryUtil.CreateTelemetry(diagnosticSource, builderName, builderProperties, strategyName, strategyType);
+        Telemetry = TelemetryUtil.CreateTelemetry(diagnosticSource, builderName, builderInstanceName, builderProperties, strategyName, strategyType);
         Randomizer = randomizer;
     }
 
@@ -34,6 +36,11 @@ internal ResilienceStrategyBuilderContext(
     /// </summary>
     public string? BuilderName { get; }
 
+    /// <summary>
+    /// Gets the instance name of the builder.
+    /// </summary>
+    public string? BuilderInstanceName { get; }
+
     /// <summary>
     /// Gets the custom properties attached to the builder.
     /// </summary>

src/Polly.Core/Telemetry/ResilienceTelemetrySource.cs

@@ -4,6 +4,7 @@ namespace Polly.Telemetry;
 /// The source of resilience telemetry events.
 /// </summary>
 /// <param name="BuilderName">The builder name.</param>
+/// <param name="BuilderInstanceName">The builder instance name.</param>
 /// <param name="BuilderProperties">The builder properties.</param>
 /// <param name="StrategyName">The strategy name. </param>
 /// <param name="StrategyType">The strategy type.</param>
@@ -12,6 +13,7 @@ namespace Polly.Telemetry;
 /// </remarks>
 public sealed record class ResilienceTelemetrySource(
     string? BuilderName,
+    string? BuilderInstanceName,
     ResilienceProperties BuilderProperties,
     string? StrategyName,
     string StrategyType);

src/Polly.Core/Telemetry/TelemetryUtil.cs

@@ -6,16 +6,15 @@ internal static class TelemetryUtil
 
     internal const string ExecutionAttempt = "ExecutionAttempt";
 
-    internal static readonly ResiliencePropertyKey<string> StrategyKey = new("Polly.StrategyKey");
-
     public static ResilienceStrategyTelemetry CreateTelemetry(
         DiagnosticSource? diagnosticSource,
         string? builderName,
+        string? builderInstanceName,
         ResilienceProperties builderProperties,
         string? strategyName,
         string strategyType)
     {
-        var telemetrySource = new ResilienceTelemetrySource(builderName, builderProperties, strategyName, strategyType);
+        var telemetrySource = new ResilienceTelemetrySource(builderName, builderInstanceName, builderProperties, strategyName, strategyType);
 
         return new ResilienceStrategyTelemetry(telemetrySource, diagnosticSource);
     }

src/Polly.Extensions/Telemetry/Log.cs

@@ -12,10 +12,7 @@ internal static partial class Log
         EventId = 0,
         Message = "Resilience event occurred. " +
                 "EventName: '{EventName}', " +
-                "Builder Name: '{BuilderName}', " +
-                "Strategy Name: '{StrategyName}', " +
-                "Strategy Type: '{StrategyType}', " +
-                "Strategy Key: '{StrategyKey}', " +
+                "Source: '{BuilderName}[{BuilderInstance}]/{StrategyType}[{StrategyName}]', " +
                 "Operation Key: '{OperationKey}', " +
                 "Result: '{Result}'",
         EventName = "ResilienceEvent")]
@@ -24,9 +21,9 @@ public static partial void ResilienceEvent(
         LogLevel logLevel,
         string eventName,
         string? builderName,
+        string? builderInstance,
         string? strategyName,
         string strategyType,
-        string? strategyKey,
         string? operationKey,
         object? result,
         Exception? exception);
@@ -35,23 +32,21 @@ public static partial void ResilienceEvent(
         1,
         LogLevel.Debug,
         "Resilience strategy executing. " +
-        "Builder Name: '{BuilderName}', " +
-        "Strategy Key: '{StrategyKey}', " +
+        "Source: '{BuilderName}[{BuilderInstance}]', " +
         "Operation Key: '{OperationKey}', " +
         "Result Type: '{ResultType}'",
         EventName = "StrategyExecuting")]
     public static partial void ExecutingStrategy(
         this ILogger logger,
         string? builderName,
-        string? strategyKey,
+        string? builderInstance,
         string? operationKey,
         string resultType);
 
     [LoggerMessage(
         EventId = 2,
         Message = "Resilience strategy executed. " +
-            "Builder Name: '{BuilderName}', " +
-            "Strategy Key: '{StrategyKey}', " +
+            "Source: '{BuilderName}[{BuilderInstance}]', " +
             "Operation Key: '{OperationKey}', " +
             "Result Type: '{ResultType}', " +
             "Result: '{Result}', " +
@@ -62,7 +57,7 @@ public static partial void StrategyExecuted(
         this ILogger logger,
         LogLevel logLevel,
         string? builderName,
-        string? strategyKey,
+        string? builderInstance,
         string? operationKey,
         string resultType,
         object? result,
@@ -73,10 +68,7 @@ public static partial void StrategyExecuted(
     [LoggerMessage(
         EventId = 3,
         Message = "Execution attempt. " +
-                "Builder Name: '{BuilderName}', " +
-                "Strategy Name: '{StrategyName}', " +
-                "Strategy Type: '{StrategyType}', " +
-                "Strategy Key: '{StrategyKey}', " +
+                "Source: '{BuilderName}[{BuilderInstance}]/{StrategyType}[{StrategyName}]', " +
                 "Operation Key: '{OperationKey}', " +
                 "Result: '{Result}', " +
                 "Handled: '{Handled}', " +
@@ -88,9 +80,9 @@ public static partial void ExecutionAttempt(
         this ILogger logger,
         LogLevel level,
         string? builderName,
+        string? builderInstance,
         string? strategyName,
         string strategyType,
-        string? strategyKey,
         string? operationKey,
         object? result,
         bool handled,

src/Polly.Extensions/Telemetry/ResilienceTelemetryDiagnosticSource.cs

@@ -54,9 +54,9 @@ private static void AddCommonTags(TelemetryEventArguments args, ResilienceTeleme
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.EventName, args.Event.EventName));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.EventSeverity, args.Event.Severity.AsString()));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.BuilderName, source.BuilderName));
+        enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.BuilderInstance, source.BuilderInstanceName));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.StrategyName, source.StrategyName));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.StrategyType, source.StrategyType));
-        enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.StrategyKey, source.BuilderProperties.GetValue(TelemetryUtil.StrategyKey, null!)));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.OperationKey, enrichmentContext.Context.OperationKey));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.ResultType, args.Context.GetResultType()));
         enrichmentContext.Tags.Add(new(ResilienceTelemetryTags.ExceptionName, args.Outcome?.Exception?.GetType().FullName));
@@ -93,7 +93,6 @@ private void MeterEvent(TelemetryEventArguments args)
 
     private void LogEvent(TelemetryEventArguments args)
     {
-        var strategyKey = args.Source.BuilderProperties.GetValue(TelemetryUtil.StrategyKey, null!);
         var result = args.Outcome?.Result;
         if (result is not null)
         {
@@ -114,9 +113,9 @@ private void LogEvent(TelemetryEventArguments args)
                     _logger,
                     level,
                     args.Source.BuilderName,
+                    args.Source.BuilderInstanceName,
                     args.Source.StrategyName,
                     args.Source.StrategyType,
-                    strategyKey,
                     args.Context.OperationKey,
                     result,
                     executionAttempt.Handled,
@@ -132,9 +131,9 @@ private void LogEvent(TelemetryEventArguments args)
                 level,
                 args.Event.EventName,
                 args.Source.BuilderName,
+                args.Source.BuilderInstanceName,
                 args.Source.StrategyName,
                 args.Source.StrategyType,
-                strategyKey,
                 args.Context.OperationKey,
                 result,
                 args.Outcome?.Exception);

src/Polly.Extensions/Telemetry/ResilienceTelemetryTags.cs

@@ -8,12 +8,12 @@ internal class ResilienceTelemetryTags
 
     public const string BuilderName = "builder-name";
 
+    public const string BuilderInstance = "builder-instance";
+
     public const string StrategyName = "strategy-name";
 
     public const string StrategyType = "strategy-type";
 
-    public const string StrategyKey = "strategy-key";
-
     public const string ResultType = "result-type";
 
     public const string OperationKey = "operation-key";