chore: add e2e lifecycle test and workflow

[ava-silver]

What does this PR do?

Adds the end-to-end instrumentation lifecycle test for serverless-plugin-datadog on AWS Lambda, plus its harness, README, and CI workflow. lambda.test.ts drives a Serverless Framework fixture through the full contract:

1. APPLY -- sls deploy; the plugin instruments the function. Assert config present (pinned Datadog Node + extension layers, redirected handler, DD_* env, identifying tags).
2. TRIGGER -- lambda invoke, then poll the Datadog API until spans and logs carrying the run identity (service/env/version/run id) appear.
3. RE-APPLY -- redeploy; assert the function config is byte-for-byte unchanged (no diff, no double-wrap or duplicated layers).
4. REMOVE -- sls remove; assert the function no longer exists.

Provision and APPLY coincide here -- the plugin runs as part of sls deploy, so there's no separate uninstrumented baseline. helpers/e2e.config.ts holds the repo-specific bits: naming, retry patterns, expected layer ARNs read from the plugin's own src/layers.json, and the verifier contract.

Infrastructure

The "tool under test" is the plugin itself, built from src and npm pack'd into a tarball that's installed into the fixture -- not a published release -- so a failure blames the plugin.

flowchart LR
  src["serverless-plugin-datadog<br/>(src, under test)"]
  tarball["npm pack tarball"]
  fixture["sls fixture<br/>(serverless.yml + handler)"]
  ddAcct["Public DD layer account"]
  fn["Workload Lambda"]

  src -->|build + pack| tarball
  tarball -->|installed into| fixture
  fixture -->|sls deploy: APPLY instruments| fn
  ddAcct -->|Node + Extension layers| fn

Loading

setup.sh packs and installs the plugin via a tarball rather than an npm file: dep, which would recurse (the fixture lives under the repo root). The Datadog API key is passed inline through serverless.yml and surfaces as DD_API_KEY on the function; CI mints it so the workload ships to the org the suite queries. sls deploy provisions the function through a CloudFormation stack; REMOVE/teardown is sls remove, always.

Motivation

Gives the plugin a real instrumentation lifecycle test against live AWS + Datadog, so a regression in layer pinning, handler redirect, env wiring, or telemetry flow fails CI.

Testing Guidelines

.github/workflows/e2e.yml runs the suite behind src/** + e2e/** path filters. AWS creds come from OIDC, Datadog creds from dd-sts -- no long-lived secrets, and a missing credential fails loudly rather than skipping green.

Ran the full suite end-to-end locally against the serverless sandbox -- all phases plus teardown pass.

Additional Notes

Layer/extension versions and the runtime are pinned (src/layers.json, overridable via env) so failures blame the plugin, not an upstream bump. frameworkVersion is pinned to 3 to avoid the Serverless v4 login flow in CI.

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

[ava-silver]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• chore: add e2e lifecycle test and workflow #710 👈 (View in Graphite)
• chore: add e2e lambda fixture #709
• chore: add e2e synced shared helpers #708
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.69%. Comparing base (0c280ce) to head (d8d9b06).

Additional details and impacted files

@@                           Coverage Diff                            @@
##           ava.silver/chore/add-e2e-lambda-fixture     #710   +/-   ##
========================================================================
  Coverage                                    77.69%   77.69%           
========================================================================
  Files                                           12       12           
  Lines                                         1112     1112           
  Branches                                       350      350           
========================================================================
  Hits                                           864      864           
  Misses                                         118      118           
  Partials                                       130      130           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[datadog-prod-us1-3]

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 1 Pipeline job failed

e2e | Lambda e2e (Node 20)     

Useful? React with 👍 / 👎

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: d8d9b06 | Docs | Datadog PR Page | Give us feedback!}