fix: Impose a 127 character limit on the Lambda function handler when the package type is set to zip

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

@@ -1,6 +1,13 @@
 ; Shipped analyzer releases
 ; https://github.com/dotnet/roslyn-analyzers/blob/master/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
 
+## Release 1.5.1
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+AWSLambda0118 | AWSLambdaCSharpGenerator | Error | Maximum Handler Length Exceeded
+
 ## Release 1.5.0
 ### New Rules
 

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

@@ -138,5 +138,12 @@ public static class DiagnosticDescriptors
             category: "AWSLambdaCSharpGenerator",
             DiagnosticSeverity.Error,
             isEnabledByDefault: true);
+
+        public static readonly DiagnosticDescriptor MaximumHandlerLengthExceeded = new DiagnosticDescriptor(id: "AWSLambda0118",
+            title: "Maximum Handler Length Exceeded",
+            messageFormat: "The handler string '{0}' exceeds the maximum length of 127 characters. Please trim down your project namespace to stay within the character limit.",
+            category: "AWSLambdaCSharpGenerator",
+            DiagnosticSeverity.Error,
+            isEnabledByDefault: true);
     }
 }

Libraries/src/Amazon.Lambda.Annotations.SourceGenerator/Validation/LambdaFunctionValidator.cs

@@ -28,6 +28,15 @@ internal static bool ValidateFunction(GeneratorExecutionContext context, IMethod
                 diagnostics.Add(Diagnostic.Create(DiagnosticDescriptors.InvalidResourceName, methodLocation));
             }
 
+            // Check the handler length does not exceed 127 characters when the package type is set to zip
+            // The official AWS docs state a 128 character limit on the Lambda handler. However, there is an open issue where the last character is stripped off
+            // when the handler is exactly 128 characters long. Hence, we are enforcing a 127 character limit.
+            // https://github.com/aws/aws-lambda-dotnet/issues/1642
+            if (lambdaFunctionModel.PackageType == LambdaPackageType.Zip && lambdaFunctionModel.Handler.Length > 127)
+            {
+                diagnostics.Add(Diagnostic.Create(DiagnosticDescriptors.MaximumHandlerLengthExceeded, methodLocation, lambdaFunctionModel.Handler));
+            }
+
             // Check for Serializer attribute
             if (!lambdaMethodSymbol.ContainingAssembly.HasAttribute(context, TypeFullNames.LambdaSerializerAttribute))
             {

Libraries/test/Amazon.Lambda.Annotations.SourceGenerators.Tests/Snapshots/ServerlessTemplates/sqsEvents.template

@@ -35,15 +35,18 @@
         }
       },
       "Properties": {
-        "Runtime": "dotnet6",
-        "CodeUri": ".",
         "MemorySize": 512,
         "Timeout": 30,
         "Policies": [
           "AWSLambdaBasicExecutionRole"
         ],
-        "PackageType": "Zip",
-        "Handler": "TestProject::TestServerlessApp.SQSEventExamples.ValidSQSEvents_ProcessMessages_Generated::ProcessMessages",
+        "PackageType": "Image",
+        "ImageUri": ".",
+        "ImageConfig": {
+          "Command": [
+            "TestProject::TestServerlessApp.SQSEventExamples.ValidSQSEvents_ProcessMessages_Generated::ProcessMessages"
+          ]
+        },
         "Events": {
           "queue1": {
             "Type": "SQS",
@@ -109,15 +112,18 @@
         }
       },
       "Properties": {
-        "Runtime": "dotnet6",
-        "CodeUri": ".",
         "MemorySize": 512,
         "Timeout": 30,
         "Policies": [
           "AWSLambdaBasicExecutionRole"
         ],
-        "PackageType": "Zip",
-        "Handler": "TestProject::TestServerlessApp.SQSEventExamples.ValidSQSEvents_ProcessMessagesWithBatchFailureReporting_Generated::ProcessMessagesWithBatchFailureReporting",
+        "PackageType": "Image",
+        "ImageUri": ".",
+        "ImageConfig": {
+          "Command": [
+            "TestProject::TestServerlessApp.SQSEventExamples.ValidSQSEvents_ProcessMessagesWithBatchFailureReporting_Generated::ProcessMessagesWithBatchFailureReporting"
+          ]
+        },
         "Events": {
           "queue3": {
             "Type": "SQS",

Libraries/test/Amazon.Lambda.Annotations.SourceGenerators.Tests/SourceGeneratorTests.cs

@@ -1330,6 +1330,31 @@ public async Task VerifyValidSQSEvents()
             }.RunAsync();
         }
 
+        [Fact]
+        public async Task ExceededMaximumHandlerLength()
+        {
+            await new VerifyCS.Test
+            {
+                TestState =
+                {
+                    Sources =
+                    {
+                        (Path.Combine("TestServerlessApp", "PlaceholderClass.cs"), await File.ReadAllTextAsync(Path.Combine("TestServerlessApp", "PlaceholderClass.cs"))),
+                        (Path.Combine("TestServerlessApp", "ExceededMaximumHandlerLength.cs"), await File.ReadAllTextAsync(Path.Combine("TestServerlessApp", "ExceededMaximumHandlerLength.cs.error"))),
+                        (Path.Combine("Amazon.Lambda.Annotations", "LambdaFunctionAttribute.cs"), await File.ReadAllTextAsync(Path.Combine("Amazon.Lambda.Annotations", "LambdaFunctionAttribute.cs"))),
+                        (Path.Combine("TestServerlessApp", "AssemblyAttributes.cs"), await File.ReadAllTextAsync(Path.Combine("TestServerlessApp", "AssemblyAttributes.cs"))),
+                    },
+                    ExpectedDiagnostics =
+                    {
+                         DiagnosticResult
+                            .CompilerError("AWSLambda0118")
+                            .WithSpan($"TestServerlessApp{Path.DirectorySeparatorChar}ExceededMaximumHandlerLength.cs", 9, 9, 13, 10)
+                            .WithArguments("TestProject::TestServerlessApp.ExceededMaximumHandlerLength_SayHelloXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX_Generated::SayHelloXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX")
+                    },
+                }
+            }.RunAsync();
+        }
+
         public void Dispose()
         {
             File.Delete(Path.Combine("TestServerlessApp", "serverless.template"));

Libraries/test/TestServerlessApp/ExceededMaximumHandlerLength.cs.error

@@ -0,0 +1,15 @@
+using System;
+using Amazon.Lambda.Annotations;
+
+namespace TestServerlessApp
+{
+    public class ExceededMaximumHandlerLength
+    {
+        // This fails because generated handler is longer than 127 characters
+        [LambdaFunction]
+        public string SayHelloXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX()
+        {
+            return "Hello, World!";
+        }
+    }
+}

Libraries/test/TestServerlessApp/SQSEventExamples/InvalidSQSEvents.cs.error

@@ -12,72 +12,72 @@ namespace TestServerlessApp.SQSEventExamples
 
     public class InvalidSQSEvents
     {
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue", BatchSize = 0, MaximumBatchingWindowInSeconds = 302, MaximumConcurrency = 1)]
         public void ProcessMessageWithInvalidSQSEventAttributes(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue")]
         public void ProcessMessageWithInvalidParameters(SQSEvent evnt, bool invalidParameter1, int invalidParameter2)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue")]
         public bool ProcessMessageWithInvalidReturnType(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
             return true;
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [RestApi(LambdaHttpMethod.Get, "/")]
         [SQSEvent("@testQueue")]
         public void ProcessMessageWithMultipleEventTypes(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("test-queue")]
         public void ProcessMessageWithInvalidQueueArn(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue", ResourceName = "sqs-event-source")]
         public void ProcessMessageWithInvalidResourceName(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue", ResourceName = "")]
         public void ProcessMessageWithEmptyResourceName(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue", BatchSize = 100)]
         public void ProcessMessageWithMaximumBatchingWindowInSecondsNotSpecified(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("@testQueue", BatchSize = 100, MaximumBatchingWindowInSeconds = 0)]
         public void ProcessMessageWithMaximumBatchingWindowInSecondsLessThanOne(SQSEvent evnt)
         {
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("arn:aws:sqs:us-east-2:444455556666:test-queue.fifo", BatchSize = 100, MaximumBatchingWindowInSeconds = 5)]
         public void ProcessMessageWithFifoQueue(SQSEvent evnt)
         {

Libraries/test/TestServerlessApp/SQSEventExamples/ValidSQSEvents.cs.txt

@@ -12,7 +12,7 @@ namespace TestServerlessApp.SQSEventExamples
 
     public class ValidSQSEvents
     {
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("arn:aws:sqs:us-east-2:444455556666:queue1", BatchSize = 50, MaximumBatchingWindowInSeconds = 2, MaximumConcurrency = 30, Filters = "My-Filter-1; My-Filter-2")]
         [SQSEvent("arn:aws:sqs:us-east-2:444455556666:queue2", MaximumBatchingWindowInSeconds = 5, Enabled = false)]
         [SQSEvent("arn:aws:sqs:us-east-2:444455556666:my-queue")]
@@ -22,7 +22,7 @@ namespace TestServerlessApp.SQSEventExamples
             Console.WriteLine($"Event processed: {evnt}");
         }
 
-        [LambdaFunction]
+        [LambdaFunction(PackageType = LambdaPackageType.Image)]
         [SQSEvent("arn:aws:sqs:us-east-2:444455556666:queue3")]
         public async Task<SQSBatchResponse> ProcessMessagesWithBatchFailureReporting(SQSEvent evnt)
         {

Libraries/test/TestServerlessApp/serverless.template

@@ -913,12 +913,6 @@
           "TestQueueEvent": {
             "Type": "SQS",
             "Properties": {
-              "Queue": {
-                "Fn::GetAtt": [
-                  "TestQueue",
-                  "Arn"
-                ]
-              },
               "BatchSize": 50,
               "FilterCriteria": {
                 "Filters": [
@@ -933,6 +927,12 @@
               "MaximumBatchingWindowInSeconds": 5,
               "ScalingConfig": {
                 "MaximumConcurrency": 5
+              },
+              "Queue": {
+                "Fn::GetAtt": [
+                  "TestQueue",
+                  "Arn"
+                ]
               }
             }
           }