Record http.url on cache spans for string and URL keys

[ayaangazali]

The Cache methods accept RequestInfo | URL, so the key can be a Request, a bare string, or a URL. instrumentFunction in packages/otel-cf-workers/src/instrumentation/cache.ts read the url as argArray[0].url, which only exists on a Request, so caches.default.match('https://example.com/x') and the URL form both produced a cache span with no http.url at all. Two of the three documented input shapes lost the attribute.

This pulls the url out of whichever shape was passed. I also made sanitiseURL return undefined instead of throwing on something unparseable, because it runs while building the span attributes, before the span exists, so a throw there would have surfaced inside the caller's own cache call rather than as a failed span.

There was no test file for the cache bindings, so I added one covering all three key shapes plus an unparseable one. The string and URL cases fail on current main with expected undefined to be 'https://example.com/...'. Ran the repo preflight and pnpm run check, both green. Patch changeset for @pydantic/otel-cf-workers included.

quick disclosure: worked through this with Claude Code and read the final diff myself. Freshman still learning, so if you would rather keep the attribute Request-only I am happy to drop it :)

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• .changeset/cache-url-attribute.md
• packages/otel-cf-workers/src/instrumentation/cache.ts
• packages/otel-cf-workers/test/instrumentation/cache.test.ts

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📝 Walkthrough

Walkthrough

Cache instrumentation now extracts URLs from string keys, URL objects, and request-like objects. Valid URLs are recorded as the http.url span attribute. Invalid or unsupported keys omit the attribute without throwing. Tests cover valid Request, string, and URL keys, plus invalid URLs. A patch changeset documents the behavior.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: recording http.url for string and URL cache keys.
Description check	✅ Passed	The description directly explains the cache instrumentation change, error handling, tests, and changeset.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[petyosi]

Reviewed the full diff and relevant surrounding code. No significant correctness, failure-mode, compatibility, or test-coverage issues found.

[ayaangazali]

Rebased onto current main (79bcac0) and re-verified there. Approved and clean, no conflicts.

Recap: Cache methods accept RequestInfo | URL, but the attribute was read as argArray[0].url, which only exists on a Request. String keys and URL keys both produced cache spans with no http.url, so two of the three documented input shapes lost it.

Happy to close it if you would rather not take this one.