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GraphQL Proxy Caching Advanced

This plugin provides a reverse GraphQL proxy cache implementation for Kong. It caches response entities based on configuration. It can cache by GraphQL query or vary headers. Cache entities are stored for a configurable period of time, after which subsequent requests to the same resource will re-fetch and re-store the resource. Cache entities can also be forcefully purged via the Admin API prior to their expiration time.

Configuration Reference

This plugin is compatible with DB-less mode.

In DB-less mode, you configure Kong Gateway declaratively. Therefore, the Admin API is mostly read-only. The only tasks it can perform are all related to handling the declarative config, including:

  • Setting a target's health status in the load balancer
  • Validating configurations against schemas
  • Uploading the declarative configuration using the /config endpoint

Example plugin configuration

The following examples provide some typical configurations for enabling the graphql-proxy-cache-advanced plugin on a service.

Make the following request:

curl -X POST http://localhost:8001/services/SERVICE_NAME|SERVICE_ID/plugins \
    --data "name=graphql-proxy-cache-advanced"  \
    --data "config.strategy=memory"

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: graphql-proxy-cache-advanced-example
config: 
  strategy: memory
plugin: graphql-proxy-cache-advanced

Next, apply the KongPlugin resource to a service by annotating the service as follows:

apiVersion: v1
kind: Service
metadata:
  name: SERVICE_NAME|SERVICE_ID
  labels:
    app: SERVICE_NAME|SERVICE_ID
  annotations:
    konghq.com/plugins: graphql-proxy-cache-advanced-example
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: SERVICE_NAME|SERVICE_ID
  selector:
    app: SERVICE_NAME|SERVICE_ID

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

Note: The KongPlugin resource only needs to be defined once and can be applied to any service, consumer, or route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

Add this section to your declarative configuration file:

plugins:
- name: graphql-proxy-cache-advanced
  service: SERVICE_NAME|SERVICE_ID
  config: 
    strategy: memory

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. In the Plugins section, click Add Plugin.
  2. Find and select the GraphQL Proxy Caching Advanced plugin.

  3. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Strategy: memory
  4. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. From the Services section, click View for the service row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the GraphQL Proxy Caching Advanced plugin.
    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, select Scoped.
  6. Add the service name and ID to the Service field if it is not already pre-filled.

  7. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Strategy: memory
  8. Click Create.

The following examples provide some typical configurations for enabling the graphql-proxy-cache-advanced plugin on a route.

Make the following request:

curl -X POST http://localhost:8001/routes/ROUTE_NAME|ROUTE_ID/plugins \
  --data "name=graphql-proxy-cache-advanced"  \
    --data "config.strategy=memory"

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: graphql-proxy-cache-advanced-example
config: 
  strategy: memory
plugin: graphql-proxy-cache-advanced

Then, apply it to an ingress (route or routes) by annotating the ingress as follows:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ROUTE_NAME|ROUTE_ID
  annotations:
    kubernetes.io/ingress.class: kong
    konghq.com/plugins: graphql-proxy-cache-advanced-example
spec:
  rules:
  - host: examplehostname.com
    http:
      paths:
      - path: /bar
        backend:
          service:
            name: echo
            port:
              number: 80

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

Note: The KongPlugin resource only needs to be defined once and can be applied to any service, consumer, or route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

Add this section to your declarative configuration file:

plugins:
- name: graphql-proxy-cache-advanced
  route: ROUTE_NAME
  config: 
    strategy: memory

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. Select a route.
  2. In the Plugins section, click Add Plugin.
  3. Find and select the GraphQL Proxy Caching Advanced plugin.

  4. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Strategy: memory
  5. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Routes from the menu, then click View for the route row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the GraphQL Proxy Caching Advanced plugin.
    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, select Scoped.
  6. Add the route ID if it is not already prefilled.

  7. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Strategy: memory
  8. Click Create.

A plugin which is not associated to any service, route, or consumer is considered global, and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

The following examples provide some typical configurations for enabling the graphql-proxy-cache-advanced plugin globally.

Make the following request:

curl -X POST http://localhost:8001/plugins/ \
  --data "name=graphql-proxy-cache-advanced"  \
    --data "config.strategy=memory"

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-graphql-proxy-cache-advanced>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config: 
  strategy: memory
plugin: graphql-proxy-cache-advanced

Add a plugins entry in the declarative configuration file:

plugins:
- name: graphql-proxy-cache-advanced
  config: 
    strategy: memory

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Plugins from the menu, then click New Plugin.
  3. Find and select the GraphQL Proxy Caching Advanced plugin.
    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  4. If the option is available, set the plugin scope to Global.

  5. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Strategy: memory
  6. Click Create.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Form Parameter Description
name
required

Type: string		 The name of the plugin, in this case graphql-proxy-cache-advanced.
service.name or service.id

Type: string		 The name or ID of the service the plugin targets.

Set one of these parameters if adding the plugin to a service through the top-level /plugins endpoint.

Not required if using /services/SERVICE_NAME|SERVICE_ID/plugins.
route.name or route.id

Type: string		 The name or ID of the route the plugin targets.

Set one of these parameters if adding the plugin to a route through the top-level /plugins endpoint.

Not required if using /routes/ROUTE_NAME|ROUTE_ID/plugins.
enabled

Type: boolean

Default value: true		 Whether this plugin will be applied.
config.vary_headers
optional

Type: array of string elements

Relevant headers considered for the cache key. If undefined, none of the headers are taken into consideration.
config.cache_ttl

Type: integer

Default value: 300

TTL in seconds of cache entities. Must be a value greater than 0.
config.strategy
required

Type: string

Default value: memory

The backing data store in which to hold cached entities. Accepted value is memory.
config.memory.dictionary_name
required

Type: string

Default value: kong_db_cache

The name of the shared dictionary in which to hold cache entities when the memory strategy is selected. Note that this dictionary currently must be defined manually in the Kong Nginx template.

Strategies

GraphQL Proxy Caching Advanced Plugin is designed to support storing GraphQL proxy cache data in different backend formats. Currently the following strategies are provided:

  • memory: A lua_shared_dict. Note that the default dictionary, kong_db_cache, is also used by other plugins and elements of Kong to store unrelated database cache entities. Using this dictionary is an easy way to bootstrap the graphql-proxy-cache-advanced plugin, but it is not recommended for large-scale installations as significant usage will put pressure on other facets of Kong’s database caching operations. It is recommended to define a separate lua_shared_dict via a custom Nginx template at this time.

Cache Key

Kong keys each cache elements based on the GraphQL query that is being send in the HTTP request body. Internally, cache keys are represented as a hexadecimal-encoded MD5 sum of the concatenation of the constituent parts.

key = md5(UUID | headers | body)

Where headers contains the headers defined in vary_headers. vary_headers defaults to NONE.

Kong will return the cache key associated with a given request as the X-Cache-Key response header.

Cache Status

Kong identifies the status of the request’s proxy cache behavior via the X-Cache-Status header. There are several possible values for this header:

  • Miss: The request could be satisfied in cache, but an entry for the resource was not found in cache, and the request was proxied upstream.
  • Hit: The request was satisfied and served from cache.
  • Refresh: The resource was found in cache, but could not satisfy the request, due to Cache-Control behaviors or reaching its hard-coded cache_ttl threshold.
  • Bypass: The request could not be satisfied from cache based on plugin configuration.

Admin API

This plugin provides several endpoints to managed cache entities. These endpoints are assigned to the graphql-proxy-cache-advanced resource.

The following endpoints are provided on the Admin API to examine and purge cache entities:

Retrieve a Cache Entity

Two separate endpoints are available: one to look up a known plugin instance, and another that searches all graphql-proxy-cache-advanced plugins data stores for the given cache key. Both endpoints have the same return value.

Endpoint

/graphql-proxy-cache-advanced/:plugin_id/caches/:cache_id
Attributes Description
plugin_id The UUID of the graphql-proxy-cache-advanced plugin
cache_id The cache entity key as reported by the X-Cache-Key response header

Endpoint

/graphql-proxy-cache-advanced/:cache_id
Attributes Description
cache_id The cache entity key as reported by the X-Cache-Key response header

Response

If the cache entity exists

HTTP 200 OK

If the entity with the given key does not exist

HTTP 400 Not Found

Delete Cache Entity

Two separate endpoints are available: one to look up a known plugin instance, and another that searches all graphql-proxy-cache-advanced plugins data stores for the given cache key. Both endpoints have the same return value.

Endpoint

/graphql-proxy-cache-advanced/:plugin_id/caches/:cache_id
Attributes Description
plugin_id The UUID of the graphql-proxy-cache-advanced plugin
cache_id The cache entity key as reported by the X-Cache-Key response header

Endpoint

/graphql-proxy-cache-advanced/:cache_id
Attributes Description
cache_id he cache entity key as reported by the X-Cache-Key response header

Response

If the cache entity exists

HTTP 204 No Content

If the entity with the given key does not exist

HTTP 400 Not Found

Purge All Cache Entities

Endpoint

/graphql-proxy-cache-advanced/

Response

HTTP 204 No Content

Note that this endpoint purges all cache entities across all graphql-proxy-cache-advanced plugins.