ngs-aws-lambda

January 4, 2022 ยท View on GitHub

Next Generation Shell - custom runtime layer for AWS Lambda.

Consider this project experimental / alpha quality.

See https://github.com/ngs-lang/ngs/issues/88

Creating a Layer

Requirements:

  • docker on local machine
  • Functional AWS CLI - the script will publish the layer using AWS CLI
  • https://github.com/ngs-lang/ngs checked out to a local directory
./make-layer.ngs /path/to/sources/of/ngs

Take a note of LayerVersionArn.

If the build was OK but the publishing of the layer failed and you would like to retry the publishing after fixing the issue, run the following:

./make-layer.ngs /path/to/sources/of/ngs --no-build

How it Works

The make-layer.ngs script works roughly as follows:

  • Runs docker container with Amazon Linux.
  • Builds NGS in the container.
  • Copies out of the container:
    • the NGS binary (ngs file)
    • NGS libraries (*.ngs files)
    • the libraries (*.so* files) NGS depends on
    • ngs-version file
  • Creates a zip with the above and the bootstrap file.
  • Publishes the zip file as a layer, using the contents of ngs-version file as part of the name of the layer. Example layer name: ngs-0-2-14-alpha.

Using the Layer

The created layer provides custom runtime. See the official documentation about using custom runtimes:

https://docs.aws.amazon.com/lambda/latest/dg/runtimes-custom.html#runtimes-custom-use

Use LayerVersionArn from the output of make-layer.ngs to configure your Lambda Function.

See also the examples directory.

Debugging

To debug the bootstrap program, pass environment variable DEBUG=aws_lambda_bootstrap to the Lambda Function.

Handler

The handler function is called with two Hash objects as positional arguments: event and context, like in other languages supported by AWS Lambda.

Event Parameter

Event is arbitrary and completely depends on the invocation. Different types of events have different formats.

Context Parameter

Sample context (from a log):

{function_name=ngs-test-01, initialization_type=on-demand, log_stream_name=2022/01/04/[$LATEST]bfdd8e2d86ec44779cf284118be63e89, runtime_api=127.0.0.1:9001, log_group_name=/aws/lambda/ngs-test-01, function_version=$LATEST, function_memory_size=128, deadline_ms=1641291314318, aws_request_id=5edeb030-f279-49ae-a49c-2b54eafe7dcb, invoked_function_arn=arn:aws:lambda:eu-central-1:123456789:function:ngs-test-01, identity={}, client_context={}}