Automatically set `faas.trigger` attribute with `@opentelemetry/instrumentation-aws-lambda`

[garysassano]

Summary

Developers authoring AWS Lambda functions in TypeScript often rely on the @types/aws-lambda module to define the handler type or event source triggering the function. This information could serve as a valuable hint to automatically set the faas.trigger attribute and other related attributes in OpenTelemetry.

Proposal

By inspecting the handler or event type, the instrumentation can infer the faas.trigger attribute and enrich telemetry data accordingly.

Examples

• API Gateway (REST)

  • Handler: ApiGatewayProxyHandler
  • Event: ApiGatewayProxyEvent
    • faas.trigger ➜ http

• API Gateway (HTTP API v2)

  • Handler: ApiGatewayProxyHandlerV2
  • Event: ApiGatewayProxyEventV2
    • faas.trigger ➜ http

• EventBridge Scheduler (or Rules)

  • Handler: ScheduledHandler
  • Event: ScheduledEvent
    • faas.trigger ➜ timer

• SQS

  • Handler: SQSHandler
  • Event: SQSEvent
    • faas.trigger ➜ pubsub
    • messaging.system ➜ aws_sqs
    • messaging.operation ➜ process

• S3

  • Handler: S3Handler
  • Event: S3Event
    • faas.trigger ➜ datasource

Additional S3 Context

If the event includes an S3EventRecord, additional attributes could be derived:

• faas.document.collection ➜ Bucket Name (e.g., myBucketName)
• faas.document.operation ➜ Operation Type (e.g., insert)
• faas.document.name ➜ File Name (e.g., myFile.txt)
• faas.document.time ➜ Event Time (e.g., 2020-01-23T13:47:06Z)

Benefits

Automatically setting these attributes improves traceability and observability, reducing the burden on developers to manually add this information while adhering to OpenTelemetry semantic conventions.

[pichlermarc]

Note: Transferred from the core repo as this is a feature request only concerns @opentelemetry/instrumentation-aws-lambda.

This feature-request is pending approval/rejection by @jj22ee (component owner)

[jj22ee]

TypeScript often rely on the @types/aws-lambda module to define the handler type or event source triggering the function.

By inspecting the handler or event type, the instrumentation can infer the faas.trigger attribute and enrich telemetry data accordingly.

The @types/aws-lambda package is a DefinitelyTyped package, it only provides types/interfaces to help with development in your IDE. The actual generated JS code cannot change logic based on such types from TypeScript.

This is one of the reasons why this related PR (#2404) adds attributes for APIGW events based on what exactly is in an event, rather than checking the TypeScript types/interfaces of the handler/event (not possible).

I suppose the proposal needs to be modified so that each event source is differentiated based on the values in the event.