[PATCH 2 of 3] Upstream: allow recovery from "429 Too Many Requests" response

[Maxim Dounin]

Hello!

On Tue, Feb 28, 2017 at 03:40:00PM -0800, Piotr Sikora via nginx-devel wrote:

> # HG changeset patch
> # User Piotr Sikora <piotrsikora at google.com>
> # Date 1488324535 28800
> #      Tue Feb 28 15:28:55 2017 -0800
> # Node ID e21f12a958010e1f3e5cdc1640859e335e032ca5
> # Parent  9a63d6e990d230db0ec6b03250265447f648526e
> Upstream: allow recovery from "429 Too Many Requests" response.
> 
> This change adds "http_429" parameter to "proxy_next_upstream" for
> retrying rate-limited requests, and to "proxy_cache_use_stale" for
> serving stale cached responses after being rate-limited.
> 
> Signed-off-by: Piotr Sikora <piotrsikora at google.com>

[...]

> @@ -4115,7 +4116,8 @@ ngx_http_upstream_next(ngx_http_request_
>      if (u->peer.sockaddr) {
>  
>          if (ft_type == NGX_HTTP_UPSTREAM_FT_HTTP_403
> -            || ft_type == NGX_HTTP_UPSTREAM_FT_HTTP_404)
> +            || ft_type == NGX_HTTP_UPSTREAM_FT_HTTP_404
> +            || ft_type == NGX_HTTP_UPSTREAM_FT_HTTP_429)
>          {
>              state = NGX_PEER_NEXT;
>  

Not sure it's good idea to don't count a 429 response as a peer 
failure.  Contrary, counting it as a failure will naturally reduce 
load on the particular server, resulting in less rejects.

-- 
Maxim Dounin
http://nginx.org/