Difference between upstream_connect_timeout, upstream_send_timeout and upstream_read_timeout

Questions
1

I’m confused between “upstream_connect_timeout, upstream_send_timeout and upstream_read_timeout”. I’ve gone through documnetation - https://getkong.org/docs/0.10.x/admin-api/#add-api, but still not clear between.

2

Hi,

Those values are abstractions of their ngx_http_proxy_module counterparts which exist as NGINX directives: proxy_connect_timeout, proxy_read_timeout, and proxy_send_timeout.

They relate to various timeouts you can set for various steps of the underlying TCP stream between Kong and your remote server(s).

3

@thibaultcha In order for me to have varying timeouts per API, can I set a bigger timeout inside my custom nginx template (client_body_timeout 1200s; client_header_timeout 1200s;) and then set the upstream timeouts (upstream_send_timeout and upstream_read_timeout) per API to some smaller number per API?

4

@kkindaface These timeouts are different than the proxy timeouts. But sure, you can edit them.

5

@thibaultcha The reason i ask is …If i set the nginx level timeouts to some smaller number and my proxy/upstream timeout to a bigger number wont the nginx timeout take precedence and kill the connection even if my upstream timeout is bigger?

6

No, the Kong ones take precedence (but the timeout properties you referred to are not the same ones, again).

7

In that case, I am seeing a different behavior. I use 0.11.x. I set my upstream timeouts to 20 mins but looks like the timeout still happens at 60 seconds and I am seeing a 504 Gateway Timeout

what do the nginx level timeouts do?

EDIT: Looks like what I observed is not true, it seems to honor the upstream timeout as soon as I restarted kong. I didn’t think a restart is needed once you edit it from the dashboard

8

@thibaultcha
I think I seeing some weird behavior W.R.T the timeouts. The API level timeouts don’t seem to be taking precedence. The timeouts defined inside template file seem to take precedence always.

I have configured the following timeouts in my custom nginx template file (right before the proxy_pass):
proxy_connect_timeout 60s;
proxy_send_timeout 60s;
proxy_read_timeout 30m;

And, configured the API level timeouts via the Kong REST API as follows (milliseconds):
upstream_connect_timeout: 3000
upstream_send_timeout: 3000
upstream_read_timeout: 3000

I am seeing a timeout only after 30 minutes and not 3 seconds like one would expect.

What could I be doing wrong?

EDIT 1: The only thing I do different in my custom template is bypass the kong.balancer() phase. It seems to work as expected when I did not use my custom template. Are the timeouts getting set in the balancer phase?

EDIT 2: So it does seem like the overriding timeouts is a feature of the ngx balancer module and so it is getting set in the balancer phase. I was able to get this working for me by adding my own balancer inside the custom nginx template and set the timeout override inside that block since I cant use the kong’s balancer