How to render a ruby gem as a lambda layer

example.sh

How to render the layer from a gem
This code is copied from: https://dev.to/peterc/how-to-create-a-aws-lambda-layer-of-your-gemfile-ruby-gem-dependencies-1gfj

LAYER_NAME="my-ruby-layer"
mkdir $LAYER_NAME && cd $_

bundle init
bundle add fast_jsonparser --skip-install
rm Gemfile.lock

docker run --rm -v $PWD:/var/layer \
           -w /var/layer \
           amazon/aws-sam-cli-build-image-ruby2.7 \
           bundle install --path=ruby

mv ruby/ruby ruby/gems
zip -r layer.zip ruby

aws lambda publish-layer-version \
           --layer-name $LAYER_NAME \
           --region eu-west-1 \
           --compatible-runtimes ruby2.7 \
           --zip-file fileb://layer.zip