Will Nginx serve stale cache after expiry if was unable to refresh the cache?

[Maxim Dounin]

Hello!

On Tue, Oct 02, 2018 at 08:34:25AM +0530, Quintin Par wrote:

> Relevant code:
> 
> proxy_cache_valid   200 301 302 1d;
> 
> proxy_cache_use_stale  error timeout invalid_header updating http_500
> http_502 http_503 http_504;
> 
> proxy_cache_background_update on;
> 
> proxy_cache_lock on;
> 
> The URL in question is obviously cached for 1 day. 15 minutes after the day
> is over, the proxy gets a request and tries to refresh the content but is
> met with an error (500) from the backend. In this case, will it continue to
> serve stale until it gets a proper new 200 content?

Yes, as per "proxy_cache_use_stale updating;", nginx will serve 
stale cached response until it will be able to update the cache.

-- 
Maxim Dounin
http://mdounin.ru/