(aws-lambda-nodejs): set NODE_OPTIONS=--enable-source-maps to environments if sourceMap: true

[yamatatsu]

Description

Just providing sourceMap: true, error logs is put with stack trace that clearly shows the lines like at Runtime.handler (/functions/src/handlers/handler.ts:37:27) instead of meaningless stack trace like at async Runtime.handler (/var/task/index.js:73786:27) .

Use Case

In default, lambda functions deployed by NodejsFunction put error logs with meaningless stack trace /var/task/index.js:73679:5 as following:

MyError
    at new MyError (/var/task/index.js:73679:5)
    at handler (/var/task/index.js:73710:11)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at async Runtime.handler (/var/task/index.js:73786:27)

If users want to use source maps, it is needed to configure as following:

new NodejsFunction(this, 'lambda-function', {
  environment: {
    NODE_OPTIONS: '--enable-source-maps',
  },
  bundling: {
    sourceMap: true,
  },
});

But NODE_OPTIONS: '--enable-source-maps', is redundant because it is clear that sourceMap should be used when sourceMap: true was set.

Since Feb 14 2022, node v10.x cannot be used on lambda, so it is not needed that we consider about runtime that does not support NODE_OPTIONS=--enable-source-maps I think.
https://docs.aws.amazon.com/lambda/latest/dg/runtime-support-policy.html#:~:text=July%2030%2C%202021-,Feb%2014%2C%202022,-Node.js%208.10

Proposed Solution

When bundling. sourceMap is true, set NODE_OPTIONS=--enable-source-maps to environments as following.

class NodejsFunction extends lambda.Function {
  constructor(scope: Construct, id: string, props: NodejsFunctionProps = {}) {
    super(scope, id, {
      ...props,
      environment: getEnvironment(props),
    });
  }
}

function getEnvironment(props: NodejsFunctionProps): { [key: string]: string } | undefined {
  if (!props.bundling?.sourceMap) {
    return props.environment;
  }
  if (props.environment?.NODE_OPTIONS.includes('--enable-source-maps')) {
    return props.environment;
  }
  return {
    ...props.environment,
    NODE_OPTIONS: `${props.environment?.NODE_OPTIONS ?? ''} --enable-source-maps`.trim(),
  };
}

Other information

No response

Acknowledge

• I may be able to implement this feature request
• This feature might incur a breaking change

[vvo]

Hey there, just wanted to say that there's a huge performance impact of using --enable-source-maps for bundled code.
https://twitter.com/vvoyer/status/1498436054851981320

[corymhall]

@yamatatsu are you saying that if you do not provide the NODE_OPTIONS environment variable to the lambda function then the logs will not have the stack trace with .ts line numbers?

Because of the performance impact I'm hesitant to turn this on. It feels like this should just be added to the documentation and users can explicitly provide this if they really want it.

[yamatatsu]

@vvo Thanks for the information! I didn't know it 👀

@corymhall

are you saying that if you do not provide the NODE_OPTIONS environment variable to the lambda function then the logs will not have the stack trace with .ts line numbers?

Yup.

Because of the performance impact I'm hesitant to turn this on. It feels like this should just be added to the documentation and users can explicitly provide this if they really want it.

I agree it. And I close this issue and will open another issue.

Thank you!

[github-actions]

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[MartinLoeper]

2024 and the performance hit is still horrendous for nodejs 18.X. In case someone is wondering if this still applies...