I'd like to proxy a request to another server using proxy_pass while removing the matched path prefix. I believe that one way of doing this is as follows;
location /a/ {
proxy_pass https://website.com/
}
E.g. a request to http://localhost/a/b.html
would be proxied to https://website.com/b.html
.
As far as I am aware the issue with this in non-commercial versions on NGINX is that the DNS A record for website.com
would be loaded and cached forever on startup. I've seen a technique to workaround this by using a variable such as $request_uri
in the proxy_pass directive, thus forcing NGINX to re-resolve the DNS according to the TTL of the record.
E.g.
location /a/ {
rewrite ^/a/(.*) /$1 break;
proxy_pass https://website.com/$request_uri
}
Unfortunately, it seems that the above doesn't work as it seems to still pass the /a/ prefix to the upstream.
Essentially all I want to achieve here is to proxy a request while removing the path prefix in such a way that DNS records are not cached forever.
Thanks.
I'm not sure where you've seen it, but just using specifically
$request_uri
is certainly not going to magically make nginx resolve the domain names for you dynamically.Perhaps what was suggested was explicitly using the variables, such as
$uri
(which is a different variable), on the assumption that when the variables are in use, then the domain name is resolved individually each time, without any caching? I don't confirm or deny whether such assumption is correct, but the following will at least get rid of/a
for you.(Note that if it's indeed implemented not to cache the domain name, then you might as well want to run a local resolver, otherwise, the extra latency and downtime of your hosting provider's DNS will immediately affect your site, not to mention the possible DNS query limits of their servers.)
Perhaps a better solution would be to periodically restart nginx to automatically pick up the changes in DNS? E.g.,
nginx -s reload
orkill -HUP
? As explained in http://nginx.org/en/docs/beginners_guide.html#control and http://nginx.org/en/docs/control.html#reconfiguration, nginx never stops processing any requests during reload, so it should be a safe operation; and it'll most likely result in DNS being flushed, too.