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proxy-cache
Apache APISIX
API Gateway
Proxy Cache
This document contains information about the Apache APISIX proxy-cache Plugin, you can use it to cache the response from the Upstream.

Description

The proxy-cache Plugin can be used to cache the response from the Upstream. It can be used with other Plugins and currently supports disk-based and memory-based caching.

The data to be cached can be filtered with response codes, request modes, or more complex methods using the no_cache and cache_bypass attributes.

Attributes

Name Type Required Default Valid values Description
cache_strategy string False disk ["disk","memory"] Specifies where the cached data should be stored.
cache_zone string False disk_cache_one Specifies which cache area to use. Each cache area can be configured with different paths. Cache areas can be predefined in your configuration file (conf/config.yaml). If the specified cache area is inconsistent with the pre-defined cache area in your configuration file, the cache is invalid.
cache_key array[string] False ["$host", "$request_uri"] Key to use for caching. For example, ["$host", "$uri", "-cache-id"].
cache_bypass array[string] False Conditions in which response from cache is bypassed. Whether to skip cache retrieval. If at least one value of the string parameters is not empty and is not equal to 0 then the response will not be taken from the cache. For example, ["$arg_bypass"].
cache_method array[string] False ["GET", "HEAD"] ["GET", "POST", "HEAD"] Request methods for which the response will be cached.
cache_http_status array[integer] False [200, 301, 404] [200, 599] HTTP status codes of the Upstream response for which the response will be cached.
hide_cache_headers boolean False false When set to true, hide the Expires and Cache-Control response headers.
cache_control boolean False false When set to true, complies with Cache-Control behavior in the HTTP specification. Used only for memory strategy.
no_cache array[string] False Conditions in which the response will not be cached. If at least one value of the string parameters is not empty and is not equal to 0 then the response will not be saved.
cache_ttl integer False 300 seconds Time that a response is cached until it is deleted or refreshed. Comes in to effect when the cache_control attribute is not enabled or the proxied server does not return cache header. Used only for memory strategy.

:::note

  • The cache expiration time cannot be configured dynamically. It can only be set by the Upstream response header Expires or Cache-Control. The default expiration time is 10s if there is no Expires or Cache-Control in the Upstream response header.
  • If the Upstream service is not available and APISIX returns a 502 or 504 status code, it will be cached for 10s.
  • Variables (start with $) can be specified in cache_key, cache_bypass and no_cache. It's worth mentioning that the variable value will be an empty string if it doesn't exist.
  • You can also combine a number of variables and strings (constants), by writing them into an array, eventually, variables will be parsed and stitched together with strings.

:::

Enable Plugin

You can add your cache configuration in you APISIX configuration file (conf/config.yaml) as shown below:

apisix:
  proxy_cache:
    cache_ttl: 10s  # default cache TTL for caching on disk
    zones:
      - name: disk_cache_one
        memory_size: 50m
        disk_size: 1G
        disk_path: /tmp/disk_cache_one
        cache_levels: 1:2
    #   - name: disk_cache_two
    #     memory_size: 50m
    #     disk_size: 1G
    #     disk_path: "/tmp/disk_cache_two"
    #     cache_levels: "1:2"
      - name: memory_cache
        memory_size: 50m

Use disk-based caching

You can enable the Plugin on a Route as shown below. The Plugin uses the disk-based cache_strategy and disk_cache_one as the cache_zone by default:

:::note You can fetch the admin_key from config.yaml and save to an environment variable with the following command:

admin_key=$(yq '.deployment.admin.admin_key[0].key' conf/config.yaml | sed 's/"//g')

:::

curl http://127.0.0.1:9180/apisix/admin/routes/1 \
-H "X-API-KEY: $admin_key" -X PUT -d '
{
    "uri": "/ip",
    "plugins": {
        "proxy-cache": {
            "cache_key":  ["$uri", "-cache-id"],
            "cache_bypass": ["$arg_bypass"],
            "cache_method": ["GET"],
            "cache_http_status": [200],
            "hide_cache_headers": true,
            "no_cache": ["$arg_test"]
        }
    },
    "upstream": {
        "nodes": {
            "httpbin.org": 1
        },
        "type": "roundrobin"
    }
}'

Use memory-based caching

You can enable the Plugin on a Route with in-memory cache_strategy and a corresponding in-memory cache_zone as shown below:

curl http://127.0.0.1:9180/apisix/admin/routes/1 \
-H "X-API-KEY: $admin_key" -X PUT -d '
{
    "uri": "/ip",
    "plugins": {
        "proxy-cache": {
            "cache_strategy": "memory",
            "cache_zone": "memory_cache",
            "cache_ttl": 10
        }
    },
    "upstream": {
        "nodes": {
            "httpbin.org": 1
        },
        "type": "roundrobin"
    }
}'

Example usage

Once you have configured the Plugin as shown above, you can make an initial request:

curl http://127.0.0.1:9080/ip -i
HTTP/1.1 200 OK
···
Apisix-Cache-Status: MISS

hello

The Apisix-Cache-Status in the response shows MISS meaning that the response is not cached, as expected. Now, if you make another request, you will see that you get a cached response:

curl http://127.0.0.1:9080/ip -i
HTTP/1.1 200 OK
···
Apisix-Cache-Status: HIT

hello

If you set "cache_zone": "invalid_disk_cache" attribute to an invalid value (cache not configured in the your configuration file), then it will return a 404 response.

:::tip

To clear the cached data, you can send a request with PURGE method:

curl -i http://127.0.0.1:9080/ip -X PURGE
HTTP/1.1 200 OK

If the response code is 200, the deletion is successful. If the cached data is not found, a 404 response code will be returned.

:::

Delete Plugin

To remove the proxy-cache Plugin, you can delete the corresponding JSON configuration from the Plugin configuration. APISIX will automatically reload and you do not have to restart for this to take effect.

curl http://127.0.0.1:9180/apisix/admin/routes/1 \
-H "X-API-KEY: $admin_key" -X PUT -d '
{
    "uri": "/ip",
    "plugins": {},
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "httpbin.org": 1
        }
    }
}'