fix: handle missing X-Etcd-Index header gracefully in config_etcd#13364
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Replace assert(rev > 0) with a nil/non-positive check that logs a warning and falls through to the existing rev==0 retry path. This prevents a fatal init worker crash when the header is missing (e.g. a reverse proxy strips non-standard headers).
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Pull request overview
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Makes config_etcd resilient when the etcd response lacks the X-Etcd-Index header by avoiding a fatal assert and falling back to the existing “rev==0” retry path.
Changes:
- Replace
assert(rev > 0)with a warning +rev = 0fallback when the header is missing/invalid. - Add a regression test that simulates a response without
X-Etcd-Indexand verifies it doesn’t crash init worker.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
apisix/core/config_etcd.lua |
Avoids fatal init-worker failure by treating missing/invalid X-Etcd-Index as a retriable condition. |
t/core/config_etcd.t |
Adds coverage for the missing-header scenario and asserts a warning is logged. |
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| -- X-Etcd-Index header so do_run_watch exercises the fallback path. | ||
| local config_etcd = require("apisix.core.config_etcd") | ||
| for i = 1, 256 do | ||
| local name, val = debug.getupvalue(config_etcd.new, i) |
shreemaan-abhishek
approved these changes
May 12, 2026
shreemaan-abhishek
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shreemaan-abhishek
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interesting edge case, how did you find this?
AlinsRan
approved these changes
May 13, 2026
membphis
approved these changes
May 13, 2026
wistefan
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Jun 16, 2026
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When the etcd response is missing the
X-Etcd-Indexheader (e.g. a reverse proxy strips non-standard headers),tonumber(nil)returnsniland theassert(rev > 0)raises — killing the init worker phase with no retry.This replaces the assert with a nil/non-positive check that logs a warning and falls through to the existing
rev == 0retry path, which fetches the current revision directly from etcd.The fix makes a transient header anomaly recoverable instead of fatal.