How to Deploy a Lambda Layer Created in .NET 6.0 & C# Using AWS CDK?

[vishal-shah-25]

Hello,

I'm trying to deploy a Lambda Layer created in .NET 6.0 and C# using AWS CDK, but I'm encountering some challenges. I've noticed that I can deploy the layer using the Amazon.Lambda.Tools and the dotnet CLI with the following command:
dotnet lambda publish-layer --layer-type runtime-package-store --s3-bucket bucket-name

However, when I attempt to do the same thing with AWS CDK, I run into issues. Specifically, the Lambda Layer I deploy via the CDK does not seem to work as expected.

I also found that when deploying a Lambda Layer using the CLI with the runtime-package-store layer type, it requires setting the Lambda environment variable DOTNET_SHARED_STORE to '/opt/dotnetcore/store/' so that it can access the layer's DLL files. Without this environment variable, Lambda functions may encounter errors while running.

Now, here's where it gets interesting:

1. When I deploy the Lambda Layer via the CLI and the Lambda function via the CDK while providing the DOTNET_SHARED_STORE environment variable, everything works as expected.
2. However, when I deploy both the Lambda Layer and the Lambda function via the CDK, even when providing the DOTNET_SHARED_STORE environment variable, it doesn't seem to work correctly.

Some of the reference links I came across: (All using cli command, not cdk)
https://github.com/aws/aws-extensions-for-dotnet-cli/blob/master/docs/Layers.md
https://github.com/awsimaya/Lambda-Layers
https://aws.amazon.com/blogs/developer/aws-lambda-layers-with-net-core/

Here's a snippet of the code I'm using in my AWS CDK project:

const TestS3Layer = new lambda.LayerVersion(this, 'TestS3Layer', {
  code: lambda.Code.fromAsset('G:/POC/TestS3Layer/packages.zip'), // Can refer code here but not working...
  compatibleRuntimes: [lambda.Runtime.DOTNET_6],
  description: 'Layer created via AWs CDK.',
});

// Existing IAM role ARN
const existingRoleArn = 'arn:aws:iam::1234567890:role/service-role/NET6_Runtime_POC-role';

// Create an instance of the existing IAM role
const existingRole = iam.Role.fromRoleArn(this, 'NET6_Runtime_POC-role', existingRoleArn);

// Create lambda functio
const myFunction = new lambda.Function(this, 'TestLambdaLayerIntegrationFunction', {
  runtime: lambda.Runtime.DOTNET_6,
  handler: 'TestLambdaLayerIntegrationFunction::TestLambdaLayerIntegrationFunction.Function::FunctionHandler',
  code: lambda.Code.fromAsset('G:/POC/TestLambdaLayerIntegrationFunction/src/TestLambdaLayerIntegrationFunction/bin/Release/net6.0/'),
  memorySize: 256,
  timeout: cdk.Duration.seconds(60),
  role: existingRole,
  environment: {
    DOTNET_SHARED_STORE: '/opt/dotnetcore/store/',
  },
  description: ".Net 6 Lambda function deployed using AWS CDK.",
  layers: [TestS3Layer]
});

What am I missing or doing wrong in my CDK deployment?

If anyone could kindly provide a reference link or a code example detailing how to achieve these tasks within AWS CDK, it would be greatly appreciated!

Thanks,
Vishal

@aws-cdk-automation