# 1.9.13 and non\_idempotent **URL:** \ **Category:** NGINX\ **Created:** [March 30, 2016, 3:35am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377 "2016-03-30T03:35:51Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Rafa\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/958977/32.png) [@Rafa\_F](https://www.ruby-forum.com/u/Rafa_F)\ **Post date:** [March 30, 2016, 3:35am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/1 "2016-03-30T03:35:51Z")
If I explicitly configured to retry next upstream based on a certain http\_xxx, will that stop working if a request is a POST with 1.9.13? For other http code, I like the idea of not retry if it is non idempotent but for one http\_xxx, I want retry no matter what type of request. Thanks Frank ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [March 30, 2016, 4:48am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/2 "2016-03-30T04:48:53Z")
Hello! On Tue, Mar 29, 2016 at 06:34:59PM -0700, Frank L. wrote: > If I explicitly configured to retry next upstream based on a > certain http\_xxx, will that stop working if a request is a POST with > 1.9.13? Yes. There is no real difference between a network error and an HTTP error returned from idempotence point of view. E.g., 502 error just means that a network error happened somewhere else. > For other http code, I like the idea of not retry if it is non > idempotent but for one http\_xxx, I want retry no matter what type of > request. Just curious - which one? Note well that if you want finer control of how various HTTP errors are handled, you can use proxy\_intercept\_errors with appropriate error\_pages configured. See [Module ngx\_http\_proxy\_module](http://nginx.org/r/proxy_intercept_errors). – Maxim D. > **[nginx](http://nginx.org/)** ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [March 30, 2016, 5:04am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/3 "2016-03-30T05:04:48Z")
It’s a custom error code, think of it as if http\_404, so if the first upstream can’t handle this request , it will send “404” saying it is not for me, please try next, nginx should then send the same request to next upstream. ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [March 30, 2016, 5:27am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/4 "2016-03-30T05:27:00Z")
Hello! On Tue, Mar 29, 2016 at 08:04:33PM -0700, Frank L. wrote: > It’s a custom error code, think of it as if http\_404, so if the first > upstream can’t handle this request , it will send “404” saying it is not > for me, please try next, nginx should then send the same request to next > upstream. Well, nginx can’t handle custom error codes in proxy\_next\_upstream, so this is probably irrelevant anyway. Though I was considered excluding http\_403 and http\_404 from idempotence checks, it may make sense to do it if there are enough such use cases. > > Yes. There is no real difference between a network error and an > > handled, you can use proxy\_intercept\_errors with appropriate > > * * * > > nginx mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [mailman.nginx.org archive](http://mailman.nginx.org/mailman/listinfo/nginx) – Maxim D. > **[nginx](http://nginx.org/)** ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [April 1, 2016, 4:47am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/5 "2016-04-01T04:47:45Z")
Does that mean by default if one upstream server is down (connect error or connect timeout), nginx won’t try the next server and POST request will just fail? Thanks! Frank ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [April 1, 2016, 5:32am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/6 "2016-04-01T05:32:09Z")
Hello! On Thu, Mar 31, 2016 at 07:46:40PM -0700, Frank L. wrote: > Does that mean by default if one upstream server is down (connect error or > connect timeout), nginx won’t try the next server and POST request will > just fail? No. Quoting CHANGES ([http://nginx.org/en/CHANGES](http://nginx.org/en/CHANGES)): ``` *) Change: non-idempotent requests (POST, LOCK, PATCH) are no longer passed to the next server by default if a request has been sent ``` to a backend; the “non\_idempotent” parameter of the “proxy\_next\_upstream” directive explicitly allows retrying such requests. Connect errors doesn’t imply that a request has been sent to a backend. As long a request hasn’t been sent yet, it can be retried to another server without any problems. See docs here for more details: > **[non\_idempotent - Module ngx\_http\_proxy\_module](http://nginx.org/en/docs/http/ngx_http_proxy_module.html#non_idempotent)** – Maxim D. > **[nginx](http://nginx.org/)** ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [April 1, 2016, 5:47pm UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/7 "2016-04-01T17:47:04Z")
Can you post a quick patch on how to exclude http\_404? Thanks! Frank ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [April 2, 2016, 7:34am UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/8 "2016-04-02T07:34:13Z")
Will this work? — ngx\_http\_upstream.c.orig 2016-03-29 15:09:31.000000000 +0000 +++ ngx\_http\_upstream.c 2016-04-02 05:28:17.877466756 +0000 @@ -3990,6 +3990,7 @@ timeout = u-\>conf-\>next\_upstream\_timeout; ``` if (u->request_sent ``` - ``` && (ft_type != NGX_HTTP_UPSTREAM_FT_HTTP_404) && (r->method & (NGX_HTTP_POST|NGX_HTTP_LOCK|NGX_HTTP_PATCH))) ``` { ft\_type |= NGX\_HTTP\_UPSTREAM\_FT\_NON\_IDEMPOTENT; ---
**Author:** ![fjlj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e79b87/32.png) [@fjlj](https://www.ruby-forum.com/u/fjlj)\ **Post date:** [April 4, 2016, 3:43pm UTC](https://www.ruby-forum.com/t/1-9-13-and-non-idempotent/244377/9 "2016-04-04T15:43:03Z")
Hello! On Fri, Apr 01, 2016 at 10:33:22PM -0700, Frank L. wrote: > ``` > { > ft_type |= NGX_HTTP_UPSTREAM_FT_NON_IDEMPOTENT; > > ``` Yes, looks correct. – Maxim D. > **[nginx](http://nginx.org/)**