Support aws EventBridge instrumentation

[calindurnea]

Is your feature request related to a problem? Please describe.
I would like to have a module that enables instrumentation of AWS lambdas that use EventBridge as a trigger.

Describe the solution you'd like
When a lambda gets triggered by an EventBridge event I would like instrumentation to be tracked similarly to how the AWS SQS functions.

Describe alternatives you've considered
I have attempted to use the lambda layers and then start custom transactions to continue the tracing. When doing this I have encountered issues with the custom traces not being sent to elasticsearch, I could only see the default trace that the layer generate on a new lambda invocation, but without any other context (for example the traceparent)

I would be open to giving it a shot at implementing this myself. I am open to any feedback or guidelines.

[trentm]

Hi @calindurnea,
I (we, Elastic) won't have the time to implement this myself. I should be able to give you some support/review if you attempt to implement this yourself.

Some notes to get you started:

• The Elastic APM agents for the various languages use this shared spec that defines certain aspects of how AWS Lambda is instrumented/traced: https://github.com/elastic/apm/blob/main/specs/agents/tracing-instrumentation-aws-lambda.md#trigger-specific-instrumentation (I've linked to the subsection that talks about specific triggers.) I wouldn't expect you to add a section to this shared spec for EventBridge. However this document might help give you some context/background for the Lambda-related code in apm-agent-nodejs.git.
• Mostly I'd expect you to need to work on "lib/lambda.js" to add support for EventBridge trigger support.
• I gather https://docs.aws.amazon.com/lambda/latest/dg/with-eventbridge-scheduler.html is at least one relevant AWS Lambda dev guide doc for this. That doesn't spell out the format of the event objects that the Lambda handler will receive. Perhaps that is specified in other AWS EventBridge docs.

I haven't used EventBridge myself, so my help might be limited.
I'm not sure if there will be a good or easy story for distributed tracing, i.e. for passing around trace-id, span-id, and flags (typically done with the traceparent header in HTTP). This APM agent doesn't do anything with AWS X-Ray.

[calindurnea]

Hello @trentm,
Thank you for the reply!
I will attempt to implement this and see how it goes. I appreciate the information, and I will reach out if anything.