minhhieugma / aws-lambda-dotnet

AWS Lambda function using .NET with Docker

AWS Lambda & .NET

All things we need to deploy .NET 5 AWS Lambda Support with Container Images!

AWS provides many resources about Lambda function and how to run it with .NET. However, I see it is quite obsolete and not very clear enough for newcomers. That's why I create this place to put all things I have gone through.

Source Code Structure

• Lambda.Dotnet
  • A very simple project that we can write code and deploy it on AWS Lambda
• Lambda.Dotnet.Mediator
  • Similar to Lambda.Dotnet. However, this project has an implementation of MediatR
• Lambda.Tests
  • Help us to test the function locally before deploying to AWS Lambda

Configuration

We use appsetting.json as a normal .NET application. During testing time, we can manipulate Environment Variables via Environment.SetEnvironmentVariable

Docker

Currently, we use .NET 5 for the whole solution but we still can change it to any other .NET version. We even can build a custom Docker image as well.

• In Dockerfile, we have COPY ["nuget.config", "."] to support a private package repository.
• In case you need to run the code with .NET 6 which is not supported yet by AWS. Please let me know.

Deployment

We need to create a Lambda function with the Container image option.

• Container image, it is a lambda function option to create a function that allows running Docker in it

Image configuration - CMD

To let the Lambda function know which .NET function needs to be called when the lambda function event occurred, we have to correct ENTRYPOINT by updating CMD:

• FunctionHandler

  Lambda.Dotnet::Lambda.Dotnet.Program::FunctionHandler

  Lambda.Dotnet.Mediator::Lambda.Dotnet.Mediator.Program::FunctionHandler

• ScheduledEventHandler

  Lambda.Dotnet::Lambda.Dotnet.Program::ScheduledEventHandler

  Lambda.Dotnet.Mediator::Lambda.Dotnet.Mediator.Program::ScheduledEventHandler

• ApiGatewateHandler

Lambda.Dotnet::Lambda.Dotnet.Program::ApiGatewateHandler

Lambda.Dotnet.Mediator::Lambda.Dotnet.Mediator.Program::ApiGatewateHandler

References

There are some other resources from AWS that you might want to check out

• https://aws.amazon.com/developer/language/net/?whats-new-dotnet.sort-by=item.additionalFields.postDateTime&whats-new-dotnet.sort-order=desc
• https://aws.amazon.com/blogs/developer/net-5-aws-lambda-support-with-container-images/