Which NPM modules are preinstalled in AWS Lambda execution environment?

Question

Recently I found that aws-sdk NPM module is preinstalled in AWS Lambda nodejs8.10. And I can't find any information in the internet about it.

Which other node.js modules are pre-installed in AWS Lambda?

Answer 1

Unfortunately the docs don't seem very specific about it, but you can grab their docker images yourself and bash in to inspect them:

docker run --rm -it --entrypoint /bin/bash amazon/aws-lambda-nodejs:14

The Dockerfile has ENTRYPOINT ["/lambda-entrypoint.sh"] and by inspecting that file I was able to determine that it runs Node via /var/runtime/bootstrap.

/var/runtime/bootstrap adds various directories to NODE_PATH from which modules can be loaded:

if [ -z "$NODE_PATH" ];
then
  nodejs_mods="/opt/nodejs/node_modules"
  nodejs14_mods="/opt/nodejs/node14/node_modules"
  runtime_mods="/var/runtime/node_modules"
  task="/var/runtime:/var/task"
  export NODE_PATH="$nodejs14_mods:$nodejs_mods:$runtime_mods:$task"
fi

However /opt/nodejs doesn't exist in the image and /var/task is where Lambda puts your custom code.

So /var/runtime/node_modules is the only directory we need to inspect:

bash-4.2# cd /var/runtime
bash-4.2# npm ls
/var/runtime
└─┬ [email protected]
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  ├── [email protected] extraneous
  └── [email protected] extraneous

As you can see, only aws-sdk is preinstalled. But you could use this process to determine if they add more preinstalled deps in future versions of their Node.js runtime.

Answer 2

Only the aws-sdk package is preinstalled .

All the rest is loaded from the "node_modules" directory..

You can find information about it here:

https://docs.aws.amazon.com/lambda/latest/dg/nodejs-create-deployment-pkg.html