The default 'URL host shares >= 2 labels of suffix with yarn_rm_url
host' rule is too strict for clusters whose hostnames are single-label
(e.g. 'ccam1' through 'ccam99'). The user's cluster is reachable at
http://ccam1:8088, and they want fetch_url to work for any ccamN
host — but ccam1 and ccam50 share 0 suffix labels, so the existing
rule rejects everything.
Add an opt-in allowlist field on Connection:
allowed_url_hosts: list[str] | None
Each entry is an fnmatch glob pattern. The URL host is allowed if it
matches ANY pattern, regardless of the suffix rule. Save a Connection
with ['ccam*'] to allow ccam1, ccam2, ..., ccam99.
SSRF safety: the implementation does NOT use vanilla fnmatch on the
flat host string (because '*' in fnmatch crosses '.', so 'ccam*' would
match 'ccam50.evil.com' — a security hole). Instead, both the pattern
and the host are split on '.' and matched LABEL-BY-LABEL with the
label counts required to match exactly. So 'ccam*' matches 'ccam50'
but NOT 'ccam50.evil.com' (different label counts).
Test coverage:
- 8 new tests in tests/unit/test_fetch_url.py (glob allow, glob deny,
dot-boundary SSRF test, multiple globs, empty list, None fallback,
error message hint)
- All 21 fetch_url tests pass; 377 total.
- spark_executor/models.py: Connection.allowed_url_hosts (with description)
- spark_executor/tools/requests.py: SaveConnectionRequest.allowed_url_hosts
- spark_executor/tools/fetch_url.py: new _host_matches_any_glob helper;
_validate_url_host now takes allowed_hosts and checks globs BEFORE
the suffix rule
- tests/unit/test_fetch_url.py: 8 new tests
- README.md: fetch_url row mentions the allowlist
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
