Inject context for sfn->Lambda when no Payload exists (case 1)

[lym953]

What and why?

In Step Machine definition, if a Lambda function doesn't have Payload field, right now we are injecting context using

"Payload.$": "States.JsonMerge($$, $, false)"

This PR changes it to:

"Payload.$": "$$['Execution', 'State']"

which passes less information.

This is case #1 in this design doc: Fixing Step Function Instrumentation

Testing

Automated testing

Pass the touched tests

Manual testing

Steps

1. Make the Lambda Execution step have no Payload field
2. Build the package: yarn prepack
3. Instrument the Step Function using ./dist/cli.js stepfunctions instrument
4. Execute the State Machine

Result

1. "Payload.$": "$$['Execution', 'State']" was added to Lambda definition
2. TODO: question to reviewers: What product should we check to ensure context injection works this way?

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)

[datadog-datadog-prod-us1]

Datadog Report

Branch report: yiming.luo/fix-step-func-8
Commit report: f7222ff
Test service: datadog-ci-tests

✅ 0 Failed, 376 Passed, 0 Skipped, 1m 27.44s Total duration (2m 2.41s time saved)

[avedmala]

LGTM 🚢

[avedmala]

I think we should hold off on removing StateMachine from the schema for now

[avedmala]

thanks for updating!