feat: add mock-upstream mode for fetch/http/nextjs e2e suites

[jy-tan]

Summary

Introduce a deterministic mock-upstream path for Node SDK HTTP-style e2e suites, and refactor fetch/http/nextjs e2e apps to route external calls through shared helpers with env-based override support.

Changes

• Add shared e2e HTTP helper at src/instrumentation/libraries/e2e-common/external-http.cjs to centralize USE_MOCK_EXTERNALS and MOCK_SERVER_BASE_URL URL rewriting, external request timeout defaults, and shared Node http/https request helpers used by HTTP tests
• Add local mock service at src/instrumentation/libraries/e2e-common/mock-upstream/mock-server.js with deterministic endpoints used by current fetch/http e2e flows.
• Wire mock-upstream into fetch/http e2e compose configs (CJS + ESM), including env defaults:
  • USE_MOCK_EXTERNALS=${USE_MOCK_EXTERNALS:-1}
  • MOCK_SERVER_BASE_URL=${MOCK_SERVER_BASE_URL:-http://mock-upstream:8081}
  • EXTERNAL_HTTP_TIMEOUT_MS=${EXTERNAL_HTTP_TIMEOUT_MS:-3000}
• Update fetch, http, nextjs e2e servers (CJS + ESM) to use shared upstream URL + timeout helpers for all outbound fetch calls.
• Keep override behavior explicit so real-upstream testing remains easy by setting USE_MOCK_EXTERNALS=0.

[cubic-dev-ai]

1 issue found across 10 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/instrumentation/libraries/fetch/e2e-tests/cjs-fetch/src/index.ts">

<violation number="1" location="src/instrumentation/libraries/fetch/e2e-tests/cjs-fetch/src/index.ts:17">
P2: `withExternalTimeout()` depends on `AbortSignal.timeout`, which only exists starting in Node 16.14+. Since the project supports node >=16.0.0, these new fetch calls can crash on Node 16.0–16.13. Add a fallback when `AbortSignal.timeout` is unavailable or guard for older Node versions.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

1 issue found across 5 files (changes from recent commits).

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/instrumentation/libraries/nextjs/e2e-tests/esm-nextjs/src/app/api/weather/route.ts">

<violation number="1" location="src/instrumentation/libraries/nextjs/e2e-tests/esm-nextjs/src/app/api/weather/route.ts:51">
P2: The GET error handler now returns a 200 response with fallback data, which hides upstream failures from clients. Preserve the error status so callers can detect failures.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}