Compile for AWS Lambda

Overview

For a native executable to run in an AWS Lambda function, it must be compatible with the runtime's operating system. This repository is an example of using Docker to build a custom C++ executable that runs on AWS Lambda.

Requirements

• Docker
• Make

Usage

Enter this directory and run make:

$ cd /path/to/compile-for-aws-lambda
$ make

The build directory now contains binaries that can be packaged in the ZIP file for an AWS Lambda function:

$ tree build
build
├── libsndfile.so -> libsndfile.so.1
├── libsndfile.so.1 -> libsndfile.so.1.0.29
├── libsndfile.so.1.0.29
└── sine

The example sine program generates a sine wave at the specified frequency (Hz) and writes it as a WAV file:

$ cd build
$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:.
$ ./sine 2600 /tmp/2600.wav
$ file /tmp/2600.wav
2600.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 24 bit, mono 44100 Hz

To run the program in a Lambda function, use the child_process module in Node.js, or the subprocess module in Python.

Details

From the Running Arbitrary Executables in AWS Lambda blog post:

If you compile your own binaries, ensure that they’re either statically linked or built for the matching version of Amazon Linux.

The example sine program in this repository uses the LGPL-licensed libsndfile library. To comply with the LPGL, libsndfile must be used as a shared library; it cannot be statically linked.

Dockerfile

To compile binaries that are compatible with Amazon Linux 2, the Dockerfile starts from an Amazon Linux 2 base image:

FROM amazonlinux:2.0.20200406.0

The Dockerfile then builds and installs libsndfile and sine.

Binaries compiled in this environment will run on any AWS Lambda runtime that's based on Amazon Linux 2, such as the Node.js 12 and Python 3.8 runtimes. See AWS Lambda runtimes for a complete list.

Makefile

The Makefile creates a container from the Docker image and copies the built artifacts from the container to the host system.