Cache: ignore stale-if-error for 4xx and 5xx codes.

Previously the stale-if-error extension of the Cache-Control upstream header
triggered the return of a stale response for all error conditions that can be
specified in the proxy_cache_use_stale directive.  The list of these errors
includes both network/timeout/format errors, as well as some HTTP codes like
503, 504, 403, 429 etc.  The latter prevented a cache entry from being updated
by a response with any of these HTTP codes during the stale-if-error period.

Now stale-if-error only works for network/timeout/format errors and ignores
the upstream HTTP code.  The return of a stale response for certain HTTP codes
is still possible using the proxy_cache_use_stale directive.

This change also applies to the stale-while-revalidate extension of the
Cache-Control header, which triggers stale-if-error if it is missing.

Reported at
http://mailman.nginx.org/pipermail/nginx/2020-July/059723.html.
This commit is contained in:
Roman Arutyunyan 2020-07-29 13:28:04 +03:00
parent d961012799
commit 554916301c

View File

@ -2473,7 +2473,7 @@ ngx_http_upstream_test_next(ngx_http_request_t *r, ngx_http_upstream_t *u)
#if (NGX_HTTP_CACHE)
if (u->cache_status == NGX_HTTP_CACHE_EXPIRED
&& ((u->conf->cache_use_stale & un->mask) || r->cache->stale_error))
&& (u->conf->cache_use_stale & un->mask))
{
ngx_int_t rc;