Pydantic AWS Lambda layer

A lambda layer with a .NET runtime for all to use. License is MIT.

Versions

Microsoft.NETCore 2.1.16 and 3.1.2

The version is not strictly defined. Is the most recent one when a merge to master was performed.

Creation

To create the package we use the docker images provided by the gods, Lambci. We build this layer using lambci/lambda:build image.

Deploy

The deployment is fully automatic, performed by travis. We create the layer package using a makefile and deploy it to every region in AWS using a custom, but simple, bash script.

ARNs

Here is the full list of ARNs of the lambdas.

# Microsoft.NETCore.App 2.1
arn:aws:lambda:ap-northeast-1:558258168256:layer:dotnet21:1
arn:aws:lambda:ap-northeast-2:558258168256:layer:dotnet21:1
arn:aws:lambda:ap-south-1:558258168256:layer:dotnet21:1
arn:aws:lambda:ap-southeast-1:558258168256:layer:dotnet21:1
arn:aws:lambda:ap-southeast-2:558258168256:layer:dotnet21:1
arn:aws:lambda:ca-central-1:558258168256:layer:dotnet21:1
arn:aws:lambda:eu-central-1:558258168256:layer:dotnet21:1
arn:aws:lambda:eu-north-1:558258168256:layer:dotnet21:1
arn:aws:lambda:eu-west-1:558258168256:layer:dotnet21:1
arn:aws:lambda:eu-west-2:558258168256:layer:dotnet21:1
arn:aws:lambda:eu-west-3:558258168256:layer:dotnet21:1
arn:aws:lambda:sa-east-1:558258168256:layer:dotnet21:1
arn:aws:lambda:us-east-1:558258168256:layer:dotnet21:1
arn:aws:lambda:us-east-2:558258168256:layer:dotnet21:1
arn:aws:lambda:us-west-1:558258168256:layer:dotnet21:1
arn:aws:lambda:us-west-2:558258168256:layer:dotnet21:1

# Microsoft.NETCore.App 3.1
arn:aws:lambda:ap-northeast-1:558258168256:layer:dotnet31:1
arn:aws:lambda:ap-northeast-2:558258168256:layer:dotnet31:1
arn:aws:lambda:ap-south-1:558258168256:layer:dotnet31:1
arn:aws:lambda:ap-southeast-1:558258168256:layer:dotnet31:1
arn:aws:lambda:ap-southeast-2:558258168256:layer:dotnet31:1
arn:aws:lambda:ca-central-1:558258168256:layer:dotnet31:1
arn:aws:lambda:eu-central-1:558258168256:layer:dotnet31:1
arn:aws:lambda:eu-north-1:558258168256:layer:dotnet31:1
arn:aws:lambda:eu-west-1:558258168256:layer:dotnet31:1
arn:aws:lambda:eu-west-2:558258168256:layer:dotnet31:1
arn:aws:lambda:eu-west-3:558258168256:layer:dotnet31:1
arn:aws:lambda:sa-east-1:558258168256:layer:dotnet31:1
arn:aws:lambda:us-east-1:558258168256:layer:dotnet31:1
arn:aws:lambda:us-east-2:558258168256:layer:dotnet31:1
arn:aws:lambda:us-west-1:558258168256:layer:dotnet31:1
arn:aws:lambda:us-west-2:558258168256:layer:dotnet31:1

Usage

This was built for people who need to run custom C# scripts in lambdas but won't, or can't, use the available runtime. The following example shows how to build a compatible project and to run it in the lambda using python.

First, we need to create our C# project. The following commands will generate and build a lambda compatible Hello World. The commands will create a project using the .NET framework installed in your computer. If you want, you can pass the framework with the --framework flag. Check here for more info on the dotnet publish command.

$ dotnet new console -o example
$ cd example
$ dotnet publish -r linux-x64 --self-contained false -o ../sample

After we have our C# project built, we need to make a small alteration in the ./sample/example.runtimeconfig.json file. See this issue for more info. Just add the following to your configurations:

{
  "runtimeOptions": {
    "configProperties": {
      "System.Globalization.Invariant": true
    }
  }
}

After that, we can package it with our lambda and run .dll files using the dotnet command. See the following python function for an example. We are assuming the sample directory is in the same directory as the python script.

import subprocess

def handler(e, c):
    subprocess.run(['dotnet', '--info'])
    subprocess.run(['dotnet', 'sample/example.dll'])
    return e