kong-plugin-response-cache

A Kong plugin that will cache JSON responses in redis

How it works

When enabled, this plugin will cache JSON response bodies and headers that match the specified URI list into redis. The duration for the cached response is set in redis and Kong will continue to use the cached response until redis removes it.

The plugin will only cache JSON responses for GET request methods.

Cache Key computation

The cache key will be a concatentation of the following items, in order, each delimited with the : character

1. The URI path
2. Query parameter and value (if defined in config.vary_by_query_parameters)
3. Header name and value (if defined in config.vary_by_headers)

Query strings and headers with multiple values will have those values concatenated and command delimited. See the table below for some examples of requests and their corresponding cache key.

Query strings and headers are concatenated in the cache key in alphabetical order.

request	cache key
curl /v1/users/wshirey?is_active	/v1/users/wshirey:is_active=true
curl /v1/users/wshirey?foo=bar&is_active	/v1/users/wshirey:foo=bar:is_active=true
curl /v1/users/wshirey?foo=bar&foo=baz	/v1/users/wshirey:foo=bar,baz
curl -H "X-Custom-ID: 123" /v1/users/wshirey?is_active=true	/v1/users/wshirey:is_active=true:x-custom-id=123
curl -H "X-Custom-ID: 123" -H "X-User-ID: 456" /v1/users/wshirey?is_active=true	/v1/users/wshirey:is_active=true:x-custom-id=123:x-user-id=456
curl -H "X-Custom-ID: 123" -H "X-Custom-ID: 456" /v1/users/wshirey?is_active=true	/v1/users/wshirey:is_active=true:x-custom-id=123,456

Configuration

Similar to the built-in JWT Kong plugin, you can associate the jwt-claims-headers plugin with an api with the following request

curl -X POST http://kong:8001/apis/{api_name_or_id}/plugins \
  --data "name=response-cache" \
  --data "config.cache_policy.uris=/echo,/headers" \
  --data "config.cache_policy.vary_by_query_parameters=" \
  --data "config.cache_policy.vary_by_headers=X-Custom-ID" \
  --data "config.cache_policy.duration_in_seconds=3600" \
  --data "config.redis_host=127.0.0.1" \

form parameter	required	description
name	required	The name of the plugin to use, in this case: response-cache
cache_policy.uris	required	A comma delimited list of URIs that Kong will cache responses. Supports regular expressions.
cache_policy.vary_by_query_parameters	optional	A comma delimited list of query parameters to use to compute cache key.
cache_policy.vary_by_headers	optional	A comma delimited list of headers to use to compute cache key.
cache_policy.duration_in_seconds	required	The amount of time in seconds that a response will be cached in redis (using the redis EXPIRE command). Redis will be responsible from removing cached responses.
redis_host	required	The hostname or IP address of the redis server.
redis_timeout	required	The timeout in milliseconds for the redis connection. Defaults to 2000 milliseconds.
redis_port	optional	The port of the redis server. Defaults to 6379.
redis_password	optional	The password (if required) to authenticate to the redis server.