NGINX - Reverse Proxy With Caching

Example

http {
    proxy_cache_path  /data/nginx/cache  levels=1:2    keys_zone=STATIC:10m
    inactive=24h  max_size=1g;
    server {
        location / {
            proxy_pass             http://1.2.3.4;
            proxy_set_header       Host $host;
            proxy_buffering        on;
            proxy_cache            STATIC;
            proxy_cache_valid      200  1d;
            proxy_cache_use_stale  error timeout invalid_header updating
                                   http_500 http_502 http_503 http_504;
        }
    }
}

proxy_cache_path

Syntax:

proxy_cache_path path [levels=levels] [use_temp_path=on|off] keys_zone=name:size [inactive=time] [max_size=size] [manager_files=number] [manager_sleep=time] [manager_threshold=time] [loader_files=number] [loader_sleep=time] [loader_threshold=time] [purger=on|off] [purger_files=number] [purger_sleep=time] [purger_threshold=time];

Sets the path and other parameters of a cache. Cache data are stored in files. The file name in a cache is a result of applying the MD5 function to the cache key. The levels parameter defines hierarchy levels of a cache: from 1 to 3, each level accepts values 1 or 2. For example, in the following configuration .

proxy_pass

Syntax:

proxy_pass URL;

Sets the protocol and address of a proxied server and an optional URI to which a location should be mapped. As a protocol, “http” or “https” can be specified. The address can be specified as a domain name or IP address, and an optional port:

proxy_pass http://localhost:8000/uri/;

or as a UNIX-domain socket path specified after the word “unix” and enclosed in colons:

proxy_pass http://unix:/tmp/backend.socket:/uri/;

proxy_set_header

Syntax:

proxy_set_header field value;

Default: 	
proxy_set_header Host $proxy_host;
proxy_set_header Connection close;

proxy_buffering

Syntax:

proxy_buffering on | off;

Default: 	
proxy_buffering on;

proxy_cache

Syntax:

proxy_cache_use_stale error | timeout | invalid_header | updating | http_500 | http_502 | http_503 | http_504 | http_403 | http_404 | http_429 | off ...;

Default:
proxy_cache_use_stale off;

Determines in which cases a stale cached response can be used during communication with the proxied server.

proxy_cache_valid

Syntax:

roxy_cache_valid [code ...] time;

Sets caching time for different response codes. For example, the following directives

    proxy_cache_valid 200 302 10m;
    proxy_cache_valid 404      1m;

set 10 minutes of caching for responses with codes 200 and 302 and 1 minute for responses with code 404.

If only caching time is specified

    proxy_cache_valid 5m;

then only 200, 301, and 302 responses are cached.

In addition, the any parameter can be specified to cache any responses:

    proxy_cache_valid 200 302 10m;
    proxy_cache_valid 301      1h;
    proxy_cache_valid any      1m;

proxy_cache_use_stale

Syntax:

proxy_cache_use_stale error | timeout | invalid_header | updating | http_500 | http_502 | http_503 | http_504 | http_403 | http_404 | http_429 | off ...;

Default: 	
proxy_cache_use_stale off;

Determines in which cases a stale cached response can be used during communication with the proxied server.

Sources

• https://www.nginx.com/resources/wiki/start/topics/examples/reverseproxycachingexample/
• https://nginx.org/en/docs/http/ngx_http_proxy_module.html

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