[BUG] Missing timeouts on 5 outbound HTTP calls outside mod_ci (follow-up to #943)

utility.py、mod_auth/controllers.py、mailer.py、mod_upload/controllers.py に記載されている5つの呼び出し箇所から始め、mod_ci/controllers.py の timeout 定数および mod_auth/controllers.py:185 にある既存の呼び出しと比較します。tests/test_utility.py を拡張し、その他の影響を受ける呼び出しに対する assertions を追加します。5つすべての outbound requests が合意した timeout を使用し、関連するテストが成功すれば完了です。

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Summary

#942 identified "GitHub API calls without timeouts" as a critical reliability gap, and #943 fixed it — but only within mod_ci/controllers.py. The audit table in #942 only enumerated call sites in that one file.

Five outbound HTTP calls in utility.py, mod_auth/controllers.py, mailer.py and mod_upload/controllers.py still have no timeout=. Since requests has no default timeout, each of these blocks its worker indefinitely if the remote end accepts the TCP connection but never responds.

Affected call sites

#	File	Call	Reached from
1	utility.py:140	requests.get('https://api.github.com/meta', ...)	unauthenticated POST /start-ci
2	mod_auth/controllers.py:212	requests.post(...) OAuth token exchange	GET /account/github_callback
3	mod_auth/controllers.py:142	session.post(...) token validity check	github_token_validity()
4	mailer.py:45	requests.post(...) Mailgun send	signup, password reset
5	mod_upload/controllers.py:106	session.post(...) create GitHub issue	upload flow

Why site 1 is the most serious

The outbound call happens before any authentication, because fetching the IP allowlist is the first check:

POST /start-ci                          <- no auth required to send this
  └─ @request_from_github()             utility.py:61
      └─ is_github_web_hook_ip()        utility.py:110   <- FIRST check
          └─ get_cached_web_hook_blocks()   utility.py:126
              └─ requests.get(...)      utility.py:140   <- no timeout

The IP allowlist cannot gate this call, because the call is what retrieves the allowlist.

There is also a cache-invalidation flaw that amplifies it. In get_cached_web_hook_blocks(), the KeyError branch logs the failure but never updates cached_load_time, and cached_web_hook_blocks stays empty. Since the guard is:

if len(cached_web_hook_blocks) == 0 or cache_has_expired(cached_load_time):

...an unexpected payload from the GitHub meta API means the cache never populates and every subsequent webhook request re-fetches. Combined with the missing timeout, that turns one hung call into one hung worker per inbound request.

I'd rate the overall severity as moderate rather than critical: it requires GitHub's API to be hanging rather than merely down (a refused connection fails fast). It is primarily a resilience-under-upstream-failure problem, which is exactly the class #942 was opened to address.

Reproduction

A listener that accepts the connection and never replies reproduces the hang. This is the specific failure mode that a ConnectionError handler does not catch:

python -c "import socket; s=socket.socket(); s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1); s.bind(('127.0.0.1', 9999)); s.listen(1); input()"

Point any of the five call sites at http://127.0.0.1:9999 and the request never returns.

The convention already exists in-tree

This is an inconsistency rather than an unknown. mod_ci/controllers.py:55-63 defines named constants (GITHUB_API_TIMEOUT, GCP_API_TIMEOUT, ARTIFACT_DOWNLOAD_TIMEOUT), and mod_auth/controllers.py:185 already does it correctly:

response = session.get(url, timeout=(3.05, 10))   # line 185 - has a timeout

...43 lines below a call in the same file that does not:

response = session.post(url, json={"access_token": token})   # line 142 - no timeout

Proposed fix

Add timeout=(3.05, 10) at the five sites, matching the existing (connect, read) tuple form at mod_auth/controllers.py:185. No signatures, return types, or call sites change.

Worth noting explicitly: sites 1, 2, 3 and 5 have no exception handler, so a timeout converts a hang into a 500. That is still a strict improvement (a fast, logged failure beats a wedged worker), but adding handlers could be a sensible follow-up if you'd prefer that in the same PR.

Tests would assert the kwarg is actually passed, so the regression can't silently return:

mock_get.assert_called_once_with(
    'https://api.github.com/meta', auth=mock.ANY, timeout=(3.05, 10))

tests/test_utility.py already patches requests.get, so this extends cleanly.

Out of scope, happy to file separately

While tracing the above I found that is_valid_signature() (utility.py:152) raises unhandled exceptions on a malformed X-Hub-Signature header, producing a 500 instead of a clean 418:

'garbage'      -> ValueError: not enough values to unpack (expected 2, got 1)
'bogus=abc'    -> TypeError: Missing required parameter 'digestmod'
'__name__=abc' -> ValueError: unsupported hash type hashlib

hashlib.__dict__.get(hash_algorithm) performs an attribute lookup on a caller-supplied string. Real-world impact is low, since it is only reachable after the GitHub IP check passes and GitHub always sends well-formed signatures. Let me know if you'd like that as its own issue.

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I'd be glad to take this one if it's not already spoken for.