Add per-attempt retry metadata tags in OrchestrationContext.ScheduleWithRetry

src/DurableTask.Core/OrchestrationContext.cs

@@ -15,6 +15,7 @@ namespace DurableTask.Core
 {
     using System;
     using System.Collections.Generic;
+    using System.Globalization;
     using System.Threading;
     using System.Threading.Tasks;
     using Castle.DynamicProxy;
@@ -204,10 +205,31 @@ public virtual Task<T> ScheduleWithRetry<T>(Type taskActivityType, RetryOptions
         /// <param name="retryOptions">Retry policy</param>
         /// <param name="parameters">Parameters for the TaskActivity.Execute method</param>
         /// <returns>Task that represents the execution of the specified TaskActivity</returns>
+        /// <remarks>
+        ///     Per-attempt retry metadata is injected into the scheduled task's <see cref="ScheduleTaskOptions.Tags"/>
+        ///     under the reserved <c>dt.retry.*</c> tag namespace (<c>dt.retry.attempt</c>, <c>dt.retry.maxAttempts</c>).
+        ///     These tags flow through <c>ScheduleTaskOrchestratorAction.Tags</c> into the persisted
+        ///     <c>TaskScheduledEvent.Tags</c>, where consumers (Functions extension, DTS Dashboard) can read them.
+        ///     Backends that do not roundtrip <c>TaskScheduledEvent.Tags</c>
+        ///     simply drop the tags at persistence; consumers fall back to a "metadata unavailable" path with no error.
+        ///     The attempt counter is closure-local, so each call site builds its own counter; deterministic replay
+        ///     reproduces the same per-attempt values because <see cref="RetryInterceptor{T}.Invoke"/> invokes the
+        ///     closure the same number of times in the same order on replay.
+        /// </remarks>
         public virtual Task<T> ScheduleWithRetry<T>(string name, string version, RetryOptions retryOptions,
             params object[] parameters)
         {
-            Task<T> RetryCall() => ScheduleTask<T>(name, version, parameters);
+            int attempt = 0;
+            Task<T> RetryCall()
+            {
+                attempt++;
+                ScheduleTaskOptions options = ScheduleTaskOptions.CreateBuilder()
+                    .AddTag(RetryTags.Attempt, attempt.ToString(CultureInfo.InvariantCulture))
+                    .AddTag(RetryTags.MaxAttempts, retryOptions.MaxNumberOfAttempts.ToString(CultureInfo.InvariantCulture))
+                    .Build();
+                return ScheduleTask<T>(name, version, options, parameters);
+            }
+
             var retryInterceptor = new RetryInterceptor<T>(this, retryOptions, RetryCall);
             return retryInterceptor.Invoke();
         }

src/DurableTask.Core/RetryTags.cs

@@ -0,0 +1,39 @@
+//  ----------------------------------------------------------------------------------
+//  Copyright Microsoft Corporation
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//  http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//  ----------------------------------------------------------------------------------
+
+namespace DurableTask.Core
+{
+    /// <summary>
+    /// Reserved tag keys written by DTFx into <see cref="ScheduleTaskOptions.Tags"/> (and from there into
+    /// <see cref="History.TaskScheduledEvent.Tags"/>) when an activity is scheduled under a retry policy.
+    /// </summary>
+    /// <remarks>
+    /// The <c>dt.</c> prefix is reserved for DTFx-injected metadata; customers must not use it on
+    /// caller-supplied tags.
+    /// </remarks>
+    internal static class RetryTags
+    {
+        /// <summary>
+        /// 1-based attempt counter for the current schedule attempt. Decimal string in
+        /// <see cref="System.Globalization.CultureInfo.InvariantCulture"/>.
+        /// </summary>
+        public const string Attempt = "dt.retry.attempt";
+
+        /// <summary>
+        /// Policy ceiling — the <see cref="RetryOptions.MaxNumberOfAttempts"/> value from the
+        /// retry policy in effect for this schedule. Decimal string in
+        /// <see cref="System.Globalization.CultureInfo.InvariantCulture"/>.
+        /// </summary>
+        public const string MaxAttempts = "dt.retry.maxAttempts";
+    }
+}