Nginx cache without upstream / backend

cachenginxreverse-proxy

I know, nginx can act as a reverse proxy to cache files if provided with a backend.

The thing is, I already use nginx as a web-server, serving files (statics and php), and I want to know if it's possible for nginx to act as a proxy_cache with his own files ?
I know it'll not work if I put the nginx itself as an upstream.

The classic thing is :
nginx => apache backend => cached_result

What I want :
nginx => same nginx instance => cached_result

Is it possible ? And if so, how ?

Best Answer

Assuming that there is some need to cache local files I just went and added the following configuration to an nginx box and it seems to work fine straight out of the box:

proxy_cache_path /data/nginx/cache keys_zone=one:128m;
server {
  listen 127.0.0.1:80;
  server_name _;
  root /usr/share/nginx/local;
  location / {
    autoindex on;
    allow all;
    satisfy any;
    try_files $uri $uri/ =404;
  }
}

server {
  listen ipv4.addr:443 ssl http2;
  listen [ipv6addr]:443 ssl http2;
  server_name _;
  root /usr/share/nginx/html;
  include /etc/nginx/ssl.conf;
  location /local/ {
    allow all;
    satisfy any;
    proxy_cache one;
    proxy_cache_key "$host$request_uri";
    proxy_cache_min_uses 1;
    proxy_cache_methods GET HEAD;
    proxy_pass http://127.0.0.1:80/;
  }
}

Related Solutions

Nginx – How to Set Up as a Caching Reverse Proxy

I don't think that there is a way to explicitly invalidate cached items, but here is an example of how to do the rest. Update: As mentioned by Piotr in another answer, there is a cache purge module that you can use. You can also force a refresh of a cached item using nginx's proxy_cache_bypass - see Cherian's answer for more information.

In this configuration, items that aren't cached will be retrieved from example.net and stored. The cached versions will be served up to future clients until they are no longer valid (60 minutes).

Your Cache-Control and Expires HTTP headers will be honored, so if you want to explicitly set an expiration date, you can do that by setting the correct headers in whatever you are proxying to.

There are lots of parameters that you can tune - see the nginx Proxy module documentation for more information about all of this including details on the meaning of the different settings/parameters: http://nginx.org/r/proxy_cache_path

http {
  proxy_cache_path  /var/www/cache levels=1:2 keys_zone=my-cache:8m max_size=1000m inactive=600m;
  proxy_temp_path /var/www/cache/tmp; 


  server {
    location / {
      proxy_pass http://example.net;
      proxy_cache my-cache;
      proxy_cache_valid  200 302  60m;
      proxy_cache_valid  404      1m;
    }
  }
}

Nginx Stale Cache and proxy_cache_path

Turns out that this is not currently possible with Nginx. I ended up setting up Varnish with a long TTL (7 days) as well as a long grace setting (2 days). I then have a script hit each URL every few days and force a warming of the cache.

Given the amount of content that I need to cache, and how infrequently each item is accessed, I was at first concerned that the cost of running Varnish would be prohibitive (all that RAM!) -- which is why I was looking at Nginx's file based caching. However, Varnish does indeed have a file backed caching option that has been working very well for me. So far my cache is about 80GB and performing very nicely!

Best Answer

Related Solutions

Nginx – How to Set Up as a Caching Reverse Proxy

Nginx Stale Cache and proxy_cache_path

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