Application Load Balancer (ALB)

.autover/changes/alb-annotations-support.json

@@ -0,0 +1,11 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.Annotations",
+      "Type": "Minor",
+      "ChangelogMessages": [
+        "Added [ALBApi] attribute for configuring Lambda functions as targets behind an Application Load Balancer"
+      ]
+    }
+  ]
+}

Libraries/Amazon.Lambda.Annotations.slnf

@@ -16,7 +16,10 @@
       "test\\TestCustomAuthorizerApp.IntegrationTests\\TestCustomAuthorizerApp.IntegrationTests.csproj",
       "test\\TestServerlessApp.IntegrationTests\\TestServerlessApp.IntegrationTests.csproj",
       "test\\TestServerlessApp.NET8\\TestServerlessApp.NET8.csproj",
-      "test\\TestServerlessApp\\TestServerlessApp.csproj"
+      "src\\Amazon.Lambda.ApplicationLoadBalancerEvents\\Amazon.Lambda.ApplicationLoadBalancerEvents.csproj",
+      "test\\TestServerlessApp\\TestServerlessApp.csproj",
+      "test\\TestServerlessApp.ALB\\TestServerlessApp.ALB.csproj",
+      "test\\TestServerlessApp.ALB.IntegrationTests\\TestServerlessApp.ALB.IntegrationTests.csproj"
     ]
   }
 }

Libraries/Libraries.sln

@@ -151,6 +151,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestCustomAuthorizerApp.Int
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestCustomAuthorizerApp", "test\TestCustomAuthorizerApp\TestCustomAuthorizerApp.csproj", "{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestServerlessApp.ALB", "test\TestServerlessApp.ALB\TestServerlessApp.ALB.csproj", "{8F7C617D-C611-4DC6-A07C-033F13C1835D}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestServerlessApp.ALB.IntegrationTests", "test\TestServerlessApp.ALB.IntegrationTests\TestServerlessApp.ALB.IntegrationTests.csproj", "{80594C21-C6EB-469E-83CC-68F9F661CA5E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -941,6 +945,30 @@ Global
 		{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E}.Release|x64.Build.0 = Release|Any CPU
 		{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E}.Release|x86.ActiveCfg = Release|Any CPU
 		{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E}.Release|x86.Build.0 = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|x64.Build.0 = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Debug|x86.Build.0 = Debug|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|x64.ActiveCfg = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|x64.Build.0 = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|x86.ActiveCfg = Release|Any CPU
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D}.Release|x86.Build.0 = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|x64.Build.0 = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Debug|x86.Build.0 = Debug|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|x64.ActiveCfg = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|x64.Build.0 = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|x86.ActiveCfg = Release|Any CPU
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -1015,6 +1043,8 @@ Global
 		{8D03BDF3-7078-4B46-A3F1-C73BE6D6CE0D} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
 		{8EEDD576-7FC4-4FAC-A5A2-F58562753A53} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
 		{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
+		{8F7C617D-C611-4DC6-A07C-033F13C1835D} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
+		{80594C21-C6EB-469E-83CC-68F9F661CA5E} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {503678A4-B8D1-4486-8915-405A3E9CF0EB}

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

@@ -16,3 +16,7 @@ AWSLambda0128 | AWSLambdaCSharpGenerator | Error | Authorizer Payload Version Mi
 AWSLambda0129 | AWSLambdaCSharpGenerator | Error | Missing LambdaFunction Attribute
 AWSLambda0130 | AWSLambdaCSharpGenerator | Error | Invalid return type IAuthorizerResult
 AWSLambda0131 | AWSLambdaCSharpGenerator | Error | FromBody not supported on Authorizer functions
+AWSLambda0132 | AWSLambdaCSharpGenerator | Error | Invalid ALBApiAttribute
+AWSLambda0133 | AWSLambdaCSharpGenerator | Error | ALB Listener Reference Not Found
+AWSLambda0134 | AWSLambdaCSharpGenerator | Error | FromRoute not supported on ALB functions
+AWSLambda0135 | AWSLambdaCSharpGenerator | Error | Unmapped parameter on ALB function

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

@@ -242,5 +242,37 @@ public static class DiagnosticDescriptors
             category: "AWSLambdaCSharpGenerator",
             DiagnosticSeverity.Error,
             isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor InvalidAlbApiAttribute = new DiagnosticDescriptor(
+            id: "AWSLambda0132",
+            title: "Invalid ALBApiAttribute",
+            messageFormat: "Invalid ALBApiAttribute encountered: {0}",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor AlbListenerReferenceNotFound = new DiagnosticDescriptor(
+            id: "AWSLambda0133",
+            title: "ALB Listener Reference Not Found",
+            messageFormat: "The ALBApi ListenerArn references '@{0}', but no resource or parameter named '{0}' was found in the CloudFormation template. Add the listener resource to the template or correct the reference name.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor FromRouteNotSupportedOnAlb = new DiagnosticDescriptor(
+            id: "AWSLambda0134",
+            title: "FromRoute not supported on ALB functions",
+            messageFormat: "[FromRoute] is not supported on ALB functions. ALB does not support route path template parameters. Use [FromHeader], [FromQuery], or [FromBody] instead.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor AlbUnmappedParameter = new DiagnosticDescriptor(
+            id: "AWSLambda0135",
+            title: "Unmapped parameter on ALB function",
+            messageFormat: "Parameter '{0}' on ALB function has no binding attribute. Use [FromHeader], [FromQuery], [FromBody], or [FromServices], or use the ApplicationLoadBalancerRequest or ILambdaContext types.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
     }
 }

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Extensions/ParameterListExtension.cs

@@ -17,14 +17,20 @@ public static bool HasConvertibleParameter(this IList<ParameterModel> parameters
                     return false;
                 }
 
+                // ALB request types are forwarded to lambda method if specified, there is no parameter conversion required.
+                if (TypeFullNames.ALBRequests.Contains(p.Type.FullName))
+                {
+                    return false;
+                }
+
                 // ILambdaContext is forwarded to lambda method if specified, there is no parameter conversion required.
                 if (p.Type.FullName == TypeFullNames.ILambdaContext)
                 {
                     return false;
                 }
 
                 // Body parameter with target type as string doesn't require conversion because body is string by nature.
-                if (p.Attributes.Any(att => att.Type.FullName == TypeFullNames.FromBodyAttribute) && p.Type.IsString())
+                if (p.Attributes.Any(att => att.Type.FullName == TypeFullNames.FromBodyAttribute || att.Type.FullName == TypeFullNames.ALBFromBodyAttribute) && p.Type.IsString())
                 {
                     return false;
                 }

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

@@ -0,0 +1,65 @@
+using Amazon.Lambda.Annotations.ALB;
+using Microsoft.CodeAnalysis;
+using System;
+using System.Linq;
+
+namespace Amazon.Lambda.Annotations.SourceGenerator.Models.Attributes
+{
+    /// <summary>
+    /// Builder for <see cref="ALBApiAttribute"/>.
+    /// </summary>
+    public class ALBApiAttributeBuilder
+    {
+        public static ALBApiAttribute Build(AttributeData att)
+        {
+            if (att.ConstructorArguments.Length != 3)
+            {
+                throw new NotSupportedException($"{TypeFullNames.ALBApiAttribute} must have constructor with 3 arguments.");
+            }
+
+            var listenerArn = att.ConstructorArguments[0].Value as string;
+            var pathPattern = att.ConstructorArguments[1].Value as string;
+            var priority = (int)att.ConstructorArguments[2].Value;
+
+            var data = new ALBApiAttribute(listenerArn, pathPattern, priority);
+
+            foreach (var pair in att.NamedArguments)
+            {
+                if (pair.Key == nameof(data.MultiValueHeaders) && pair.Value.Value is bool multiValueHeaders)
+                {
+                    data.MultiValueHeaders = multiValueHeaders;
+                }
+                else if (pair.Key == nameof(data.HostHeader) && pair.Value.Value is string hostHeader)
+                {
+                    data.HostHeader = hostHeader;
+                }
+                else if (pair.Key == nameof(data.HttpMethod) && pair.Value.Value is string httpMethod)
+                {
+                    data.HttpMethod = httpMethod;
+                }
+                else if (pair.Key == nameof(data.ResourceName) && pair.Value.Value is string resourceName)
+                {
+                    data.ResourceName = resourceName;
+                }
+                else if (pair.Key == nameof(data.HttpHeaderConditionName) && pair.Value.Value is string httpHeaderConditionName)
+                {
+                    data.HttpHeaderConditionName = httpHeaderConditionName;
+                }
+                else if (pair.Key == nameof(data.HttpHeaderConditionValues) && !pair.Value.IsNull)
+                {
+                    data.HttpHeaderConditionValues = pair.Value.Values.Select(v => v.Value as string).ToArray();
+                }
+                else if (pair.Key == nameof(data.QueryStringConditions) && !pair.Value.IsNull)
+                {
+                    data.QueryStringConditions = pair.Value.Values.Select(v => v.Value as string).ToArray();
+                }
+                else if (pair.Key == nameof(data.SourceIpConditions) && !pair.Value.IsNull)
+                {
+                    data.SourceIpConditions = pair.Value.Values.Select(v => v.Value as string).ToArray();
+                }
+            }
+
+            return data;
+        }
+    }
+}

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

@@ -0,0 +1,25 @@
+using Amazon.Lambda.Annotations.ALB;
+using Microsoft.CodeAnalysis;
+
+namespace Amazon.Lambda.Annotations.SourceGenerator.Models.Attributes
+{
+    /// <summary>
+    /// Builder for <see cref="ALB.FromHeaderAttribute"/>.
+    /// </summary>
+    public class ALBFromHeaderAttributeBuilder
+    {
+        public static ALB.FromHeaderAttribute Build(AttributeData att)
+        {
+            var data = new ALB.FromHeaderAttribute();
+            foreach (var pair in att.NamedArguments)
+            {
+                if (pair.Key == nameof(data.Name) && pair.Value.Value is string value)
+                {
+                    data.Name = value;
+                }
+            }
+
+            return data;
+        }
+    }
+}

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

@@ -0,0 +1,25 @@
+using Amazon.Lambda.Annotations.ALB;
+using Microsoft.CodeAnalysis;
+
+namespace Amazon.Lambda.Annotations.SourceGenerator.Models.Attributes
+{
+    /// <summary>
+    /// Builder for <see cref="ALB.FromQueryAttribute"/>.
+    /// </summary>
+    public class ALBFromQueryAttributeBuilder
+    {
+        public static ALB.FromQueryAttribute Build(AttributeData att)
+        {
+            var data = new ALB.FromQueryAttribute();
+            foreach (var pair in att.NamedArguments)
+            {
+                if (pair.Key == nameof(data.Name) && pair.Value.Value is string value)
+                {
+                    data.Name = value;
+                }
+            }
+
+            return data;
+        }
+    }
+}

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

@@ -1,4 +1,5 @@
 using System;
+using Amazon.Lambda.Annotations.ALB;
 using Amazon.Lambda.Annotations.APIGateway;
 using Amazon.Lambda.Annotations.SQS;
 using Microsoft.CodeAnalysis;
@@ -30,7 +31,7 @@ public static AttributeModel Build(AttributeData att, GeneratorExecutionContext
             else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.FromQueryAttribute), SymbolEqualityComparer.Default))
             {
                 var data = FromQueryAttributeBuilder.Build(att);
-                model = new AttributeModel<FromQueryAttribute>
+                model = new AttributeModel<APIGateway.FromQueryAttribute>
                 {
                     Data = data,
                     Type = TypeModelBuilder.Build(att.AttributeClass, context)
@@ -39,7 +40,7 @@ public static AttributeModel Build(AttributeData att, GeneratorExecutionContext
             else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.FromHeaderAttribute), SymbolEqualityComparer.Default))
             {
                 var data = FromHeaderAttributeBuilder.Build(att);
-                model = new AttributeModel<FromHeaderAttribute>
+                model = new AttributeModel<APIGateway.FromHeaderAttribute>
                 {
                     Data = data,
                     Type = TypeModelBuilder.Build(att.AttributeClass, context)
@@ -108,6 +109,42 @@ public static AttributeModel Build(AttributeData att, GeneratorExecutionContext
                     Type = TypeModelBuilder.Build(att.AttributeClass, context)
                 };
             }
+            else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.ALBApiAttribute), SymbolEqualityComparer.Default))
+            {
+                var data = ALBApiAttributeBuilder.Build(att);
+                model = new AttributeModel<ALBApiAttribute>
+                {
+                    Data = data,
+                    Type = TypeModelBuilder.Build(att.AttributeClass, context)
+                };
+            }
+            else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.ALBFromQueryAttribute), SymbolEqualityComparer.Default))
+            {
+                var data = ALBFromQueryAttributeBuilder.Build(att);
+                model = new AttributeModel<ALB.FromQueryAttribute>
+                {
+                    Data = data,
+                    Type = TypeModelBuilder.Build(att.AttributeClass, context)
+                };
+            }
+            else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.ALBFromHeaderAttribute), SymbolEqualityComparer.Default))
+            {
+                var data = ALBFromHeaderAttributeBuilder.Build(att);
+                model = new AttributeModel<ALB.FromHeaderAttribute>
+                {
+                    Data = data,
+                    Type = TypeModelBuilder.Build(att.AttributeClass, context)
+                };
+            }
+            else if (att.AttributeClass.Equals(context.Compilation.GetTypeByMetadataName(TypeFullNames.ALBFromBodyAttribute), SymbolEqualityComparer.Default))
+            {
+                var data = new ALB.FromBodyAttribute();
+                model = new AttributeModel<ALB.FromBodyAttribute>
+                {
+                    Data = data,
+                    Type = TypeModelBuilder.Build(att.AttributeClass, context)
+                };
+            }
             else
             {
                 model = new AttributeModel

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

@@ -11,6 +11,7 @@ public enum EventType
         SQS,
         DynamoDB,
         Schedule,
-        Authorizer
+        Authorizer,
+        ALB
     }
 }

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

@@ -31,6 +31,10 @@ public static HashSet<EventType> Build(IMethodSymbol lambdaMethodSymbol,
                 {
                     events.Add(EventType.Authorizer);
                 }
+                else if (attribute.AttributeClass.ToDisplayString() == TypeFullNames.ALBApiAttribute)
+                {
+                    events.Add(EventType.ALB);
+                }
             }
 
             return events;

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

@@ -130,6 +130,20 @@ private static TypeModel BuildResponseType(IMethodSymbol lambdaMethodSymbol,
                         throw new ArgumentOutOfRangeException();
                 }
             }
+            else if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.ALBApiAttribute))
+            {
+                // ALB functions return ApplicationLoadBalancerResponse
+                // If the user already returns ApplicationLoadBalancerResponse, pass through the return type.
+                // Otherwise, wrap in ApplicationLoadBalancerResponse.
+                if (lambdaMethodModel.ReturnsApplicationLoadBalancerResponse)
+                {
+                    return lambdaMethodModel.ReturnType;
+                }
+                var symbol = lambdaMethodModel.ReturnsVoidOrGenericTask ?
+                    task.Construct(context.Compilation.GetTypeByMetadataName(TypeFullNames.ApplicationLoadBalancerResponse)):
+                    context.Compilation.GetTypeByMetadataName(TypeFullNames.ApplicationLoadBalancerResponse);
+                return TypeModelBuilder.Build(symbol, context);
+            }
             else
             {
                 return lambdaMethodModel.ReturnType;
@@ -277,6 +291,19 @@ private static IList<ParameterModel> BuildParameters(IMethodSymbol lambdaMethodS
                 parameters.Add(requestParameter);
                 parameters.Add(contextParameter);
             }
+            else if (lambdaMethodSymbol.HasAttribute(context, TypeFullNames.ALBApiAttribute))
+            {
+                var symbol = context.Compilation.GetTypeByMetadataName(TypeFullNames.ApplicationLoadBalancerRequest);
+                var type = TypeModelBuilder.Build(symbol, context);
+                var requestParameter = new ParameterModel
+                {
+                    Name = "__request__",
+                    Type = type,
+                    Documentation = "The ALB request object that will be processed by the Lambda function handler."
+                };
+                parameters.Add(requestParameter);
+                parameters.Add(contextParameter);
+            }
             else
             {
                 // Lambda method with no event attribute are plain lambda functions, therefore, generated method will have