Amazon.Lambda.RuntimeSupport

The Amazon.Lambda.RuntimeSupport package is a .NET Lambda Runtime Interface Client (RIC) for the Lambda Runtime API. The Lambda Runtime Interface Client allows your runtime to receive requests from and send requests to the Lambda service. It can be used for building .NET Lambda functions as either custom runtimes or container images. Starting with the .NET 6 this is also the Lambda rutime client used in managed runtimes.

Container Image support

AWS provides base images containing all the required components to run your functions packaged as container images on AWS Lambda. Starting with the AWS Lambda .NET 5 base image Amazon.Lambda.RuntimeSupport is used as the Lambda Runtime Client. The library targets .NET Standard 2.0 and can also be used in earlier versions of .NET Core that support .NET Standard like 3.1.

In the AWS Lambda .NET base image this library is preinstalled into /var/runtime directory. .NET Lambda functions using the base image do not directly interact with this package. Instead they pass in an image command or a Dockerfile CMD that indicates the .NET code to run. The format of that parameter is <assembly-name>::<full-type-name>::<function-name>.

Custom base container images where Amazon.Lambda.RuntimeSupport is not preinstalled the library can be included in the .NET Lambda function code as a class library. To learn how to build a .NET Lambda function using Amazon.Lambda.RuntimeSupport as a class library checkout the Using Amazon.Lambda.RuntimeSupport as a class library section in this README.

The Dockefile below shows how to build a Lambda function using a custom base image. In this case the base image is Microsoft's .NET 6 runtime image. This Dockerfile copies the .NET Lambda function into the /var/task directory and then uses the dotnet CLI to execute the .NET Lambda project which will initialize the Amazon.Lambda.RuntimeSupport library and start responding to Lambda events.

FROM mcr.microsoft.com/dotnet/runtime:6.0 WORKDIR /var/task COPY "bin/Release/net6.0/linux-x64/publish" . ENTRYPOINT ["/usr/bin/dotnet", "exec", "/var/task/LambdaContainerCustomBase.dll"]