Integrate [DurableExecution] with the Annotations source generator

.autover/changes/durable-execution-annotations-integration.json

@@ -0,0 +1,11 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.Annotations",
+      "Type": "Minor",
+      "ChangelogMessages": [
+        "Add [DurableExecution] attribute and source generator support for durable execution functions. A method annotated with [LambdaFunction] and [DurableExecution] generates a handler wrapper that delegates to Amazon.Lambda.DurableExecution.DurableFunction.WrapAsync, and emits a DurableConfig block plus the lambda:CheckpointDurableExecution / lambda:GetDurableExecutionState IAM permissions in the generated CloudFormation/SAM template. Validates that durable functions are executable, Zip-packaged, and have the (TInput, IDurableContext) -> Task/Task<TOutput> signature (AWSLambda0140-AWSLambda0143). Preview."
+      ]
+    }
+  ]
+}

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Amazon.Lambda.Annotations.SourceGenerator.csproj

@@ -108,6 +108,10 @@
       <Generator>TextTemplatingFilePreprocessor</Generator>
       <LastGenOutput>AuthorizerInvoke.cs</LastGenOutput>
     </None>
+    <None Update="Templates\DurableExecutionInvoke.tt">
+      <Generator>TextTemplatingFilePreprocessor</Generator>
+      <LastGenOutput>DurableExecutionInvoke.cs</LastGenOutput>
+    </None>
   </ItemGroup>
 
   <ItemGroup>
@@ -151,6 +155,11 @@
       <AutoGen>True</AutoGen>
       <DependentUpon>AuthorizerInvoke.tt</DependentUpon>
     </Compile>
+    <Compile Update="Templates\DurableExecutionInvoke.cs">
+      <DesignTime>True</DesignTime>
+      <AutoGen>True</AutoGen>
+      <DependentUpon>DurableExecutionInvoke.tt</DependentUpon>
+    </Compile>
   </ItemGroup>
 
   <ItemGroup>

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Diagnostics/AnalyzerReleases.Unshipped.md

@@ -24,3 +24,7 @@ AWSLambda0136 | AWSLambdaCSharpGenerator | Error | Invalid S3EventAttribute
 AWSLambda0137 | AWSLambdaCSharpGenerator | Error | Invalid DynamoDBEventAttribute
 AWSLambda0138 | AWSLambdaCSharpGenerator | Error | Invalid SNSEventAttribute
 AWSLambda0139 | AWSLambdaCSharpGenerator | Error | Invalid ScheduleEventAttribute
+AWSLambda0140 | AWSLambdaCSharpGenerator | Error | DurableExecution requires an executable project
+AWSLambda0141 | AWSLambdaCSharpGenerator | Error | DurableExecution requires Zip packaging
+AWSLambda0142 | AWSLambdaCSharpGenerator | Error | Invalid DurableExecution method signature
+AWSLambda0143 | AWSLambdaCSharpGenerator | Info | DurableExecution function with explicit Role needs checkpoint permissions

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Diagnostics/DiagnosticDescriptors.cs

@@ -302,5 +302,33 @@ public static class DiagnosticDescriptors
             category: "AWSLambdaCSharpGenerator",
             DiagnosticSeverity.Error,
             isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor DurableExecutionRequiresExecutable = new DiagnosticDescriptor(id: "AWSLambda0140",
+            title: "DurableExecution requires an executable project",
+            messageFormat: "A method annotated with [DurableExecution] requires the project to output an executable (set 'OutputType' to 'Exe' in the .csproj). Class library handlers are not supported for durable functions in preview.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor DurableExecutionZipOnly = new DiagnosticDescriptor(id: "AWSLambda0141",
+            title: "DurableExecution requires Zip packaging",
+            messageFormat: "A method annotated with [DurableExecution] requires PackageType to be Zip. Image (container) packaging is not supported for durable functions.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor DurableExecutionInvalidSignature = new DiagnosticDescriptor(id: "AWSLambda0142",
+            title: "Invalid DurableExecution method signature",
+            messageFormat: "A method annotated with [DurableExecution] must have the signature (TInput, Amazon.Lambda.DurableExecution.IDurableContext) returning Task or Task<TOutput>: {0}",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor DurableExecutionExplicitRoleNeedsCheckpointPolicy = new DiagnosticDescriptor(id: "AWSLambda0143",
+            title: "DurableExecution function with explicit Role needs checkpoint permissions",
+            messageFormat: "The [DurableExecution] function uses an explicit Role, so the generator will not add the durable checkpoint policy. Attach the 'lambda:CheckpointDurableExecution' and 'lambda:GetDurableExecutionState' actions to the role manually.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Info,
+            isEnabledByDefault: true);
     }
 }

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Models/Attributes/AttributeModelBuilder.cs

@@ -143,6 +143,15 @@ public static AttributeModel Build(AttributeData att, GeneratorExecutionContext
                     Type = TypeModelBuilder.Build(att.AttributeClass, context)
                 };
             }
+            else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.DurableExecutionAttribute), SymbolEqualityComparer.Default))
+            {
+                var data = DurableExecutionAttributeBuilder.Build(att);
+                model = new AttributeModel<DurableExecutionAttribute>
+                {
+                    Data = data,
+                    Type = TypeModelBuilder.Build(att.AttributeClass, context)
+                };
+            }
             else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.HttpApiAuthorizerAttribute), SymbolEqualityComparer.Default))
             {
                 var data = HttpApiAuthorizerAttributeBuilder.Build(att);

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Models/Attributes/DurableExecutionAttributeBuilder.cs

@@ -0,0 +1,35 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+using Amazon.Lambda.Annotations;
+using Microsoft.CodeAnalysis;
+
+namespace Amazon.Lambda.Annotations.SourceGenerator.Models.Attributes
+{
+    /// <summary>
+    /// Builder for <see cref="DurableExecutionAttribute"/>. Reads named arguments from the
+    /// <see cref="AttributeData"/>; assigning each property also sets its corresponding
+    /// <c>IsXxxSet</c> flag so unset values can be omitted from the generated template.
+    /// </summary>
+    public class DurableExecutionAttributeBuilder
+    {
+        public static DurableExecutionAttribute Build(AttributeData att)
+        {
+            var data = new DurableExecutionAttribute();
+
+            foreach (var pair in att.NamedArguments)
+            {
+                if (pair.Key == nameof(data.RetentionPeriodInDays) && pair.Value.Value is int retentionPeriodInDays)
+                {
+                    data.RetentionPeriodInDays = retentionPeriodInDays;
+                }
+                else if (pair.Key == nameof(data.ExecutionTimeout) && pair.Value.Value is int executionTimeout)
+                {
+                    data.ExecutionTimeout = executionTimeout;
+                }
+            }
+
+            return data;
+        }
+    }
+}

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Models/EventType.cs

@@ -13,6 +13,7 @@ public enum EventType
         DynamoDB,
         Schedule,
         Authorizer,
-        ALB
+        ALB,
+        DurableExecution
     }
 }

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Models/EventTypeBuilder.cs

@@ -46,6 +46,10 @@ public static HashSet<EventType> Build(IMethodSymbol lambdaMethodSymbol,
                 {
                     events.Add(EventType.Schedule);
                 }
+                else if (attribute.AttributeClass.ToDisplayString() == TypeFullNames.DurableExecutionAttribute)
+                {
+                    events.Add(EventType.DurableExecution);
+                }
                 else if (attribute.AttributeClass.ToDisplayString() == TypeFullNames.HttpApiAuthorizerAttribute
                     || attribute.AttributeClass.ToDisplayString() == TypeFullNames.RestApiAuthorizerAttribute)
                 {

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Models/GeneratedMethodModelBuilder.cs

@@ -63,6 +63,11 @@ private static IList<string> BuildUsings(LambdaMethodModel lambdaMethodModel,
                 namespaces.Add("Amazon.Lambda.Annotations.APIGateway");
             }
 
+            if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.DurableExecutionAttribute))
+            {
+                namespaces.Add("Amazon.Lambda.DurableExecution");
+            }
+
             return namespaces;
         }
 
@@ -71,6 +76,15 @@ private static TypeModel BuildResponseType(IMethodSymbol lambdaMethodSymbol,
         {
             var task = context.Compilation.GetTypeByMetadataName(TypeFullNames.Task1);
 
+            // Durable functions always produce Task<DurableExecutionInvocationOutput>; the generated
+            // wrapper delegates to DurableFunction.WrapAsync, which returns that envelope.
+            if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.DurableExecutionAttribute))
+            {
+                var outputType = context.Compilation.GetTypeByMetadataName(TypeFullNames.DurableExecutionInvocationOutput);
+                var genericTask = task.Construct(outputType);
+                return TypeModelBuilder.Build(genericTask, context);
+            }
+
             if (lambdaMethodModel.ReturnsIHttpResults)
             {
                 var typeStream = context.Compilation.GetTypeByMetadataName(TypeFullNames.Stream);
@@ -217,7 +231,22 @@ private static IList<ParameterModel> BuildParameters(IMethodSymbol lambdaMethodS
                 Documentation = "The ILambdaContext that provides methods for logging and describing the Lambda environment."
             };
 
-            if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.HttpApiAuthorizerAttribute))
+            // Durable functions receive the service envelope (DurableExecutionInvocationInput); the
+            // generated wrapper passes it straight to DurableFunction.WrapAsync along with the context.
+            if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.DurableExecutionAttribute))
+            {
+                var symbol = context.Compilation.GetTypeByMetadataName(TypeFullNames.DurableExecutionInvocationInput);
+                var type = TypeModelBuilder.Build(symbol, context);
+                var requestParameter = new ParameterModel
+                {
+                    Name = "__request__",
+                    Type = type,
+                    Documentation = "The durable execution service envelope that will be processed by the Lambda function handler."
+                };
+                parameters.Add(requestParameter);
+                parameters.Add(contextParameter);
+            }
+            else if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.HttpApiAuthorizerAttribute))
             {
                 // For HTTP API authorizer functions, the generated handler accepts the authorizer request type
                 var authorizerAttribute = lambdaMethodSymbol.GetAttributeData(context, TypeFullNames.HttpApiAuthorizerAttribute);