Migrating from Varnish

[Maxim Dounin]

Hello!

On Thu, Nov 23, 2017 at 09:00:52AM -0600, Andrei wrote:

> Hi all,
> 
> I've been using Varnish for 4 years now, but quite frankly I'm tired of
> using it for HTTP traffic and Nginx for SSL offloading when Nginx can just
> handle it all. One of the main issues I'm running into with the transition
> is related to cache purging, and setting custom expiry TTL's per
> zone/domain. My questions are:
> 
> - Does anyone have any recent working documentation on supported
> modules/Lua scripts which can achieve wildcard purges as well as specific
> URL purges?

Cache purging is available in nginx-plus, see 
http://nginx.org/r/proxy_cache_purge.

> - How should I go about defining custom cache TTL's for: frontpage,
> dynamic, and static content requests? Currently I have Varnish configured
> to set the ttl's based on request headers which are added in the config
> with regex matches against the host being accessed.

Normal nginx approach is to configure distinct server{} and 
location{} blocks for different content, with appropriate cache 
validity times.  For example:

    server {
        listen 80;
        server_name foo.example.com;

        location / {
            proxy_pass http://backend;
            proxy_cache one;
            proxy_cache_valid 200 5m;
        }

        location /static/ {
            proxy_pass http://backend;
            proxy_cache one;
            proxy_cache_valid 200 24h;
        }
    }

Note well that by default nginx respects what is returned by the 
backend in various response headers, and proxy_cache_valid time 
only applies if there are no explicit cache validity time set, see 
http://nginx.org/r/proxy_ignore_headers.

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