fix: Impose a 127 character limit on the Lambda function handler when…

… the package type is set to zip

Addresses #1642

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. Alternatively, you can switch to an image based deployment by setting the 'PackageType' to 'Image' to avoid the handler length restriction.",
+            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"
+                ]
               }
             }
           }