APISIX Plugin for KNative Kourier Routing Layer

Custom APISIX Plugin to Support KNative Kourier Routing Layer for Host Header Alteration. This plugin is used to override the Host header to the value of the x-knative-function header to route the request to the correct function based on the x-knative-function header. This will allow users to create single route for each function in APISIX and utilize the Kourier routing layer to propagate the request.

Installation

You need to add the plugin to the APISIX.

APISX Documentation: https://apisix.apache.org/docs/apisix/plugin-develop/#where-to-put-your-plugins

For Binary Mode

You need to add the plugin in to a sub-directory and update the conf/config.yaml file to load the plugin.

• Create a new directory in the apisix/plugins directory.
• Add the plugin in to the new directory.
• Update the conf/config.yaml file to load the plugin.

For example, you can create a directory structure like this:

├── custom_plugins
│   └── apisix
│       └── plugins
│           └── knative-kourier-router.lua

Then add this configuration into your conf/config.yaml:

apisix:
  ...
  extra_lua_path: "/path/to/custom_plugins/?.lua"
  ...
  plugins:
  - ...
  - knative-kourier-router                            # Enable the plugin

If you are using decoupled mode, you need to do the same configuration for both data plane and control plane.

For APISIX Dashboard, you need to add the plugin in the plugins section.

plugins:
  - ...
  - knative-kourier-router                            # Enable the plugin

Update Plugin Schema

You need to update the plugin schema to load the schema of the custom plugin. APISIX currently does not support loading the schema for custom plugins automatically.

• You need to export the schema using control api.
• Upload the exported schema to the conf folder.

More Information: https://apisix.apache.org/docs/dashboard/FAQ/#4-after-modifying-the-plugin-schema-or-creating-a-custom-plugin-in-apache-apisix-why-cant-i-find-it-on-the-dashboard

For Kubernetes

For Kubernetes deployment, you can mount the plugin as a configmap. Assuming you installed APISIX using official helm chart in the namespace apisix.

APISIX Helm Chart: https://github.com/apache/apisix-helm-chart/tree/master/charts

Step 1: Create the configmap

Paste the content of the plugin to the configmap as follows.

apiVersion: v1
kind: ConfigMap
metadata:
  name: knative-kourier-router-plugin
data:
  knative-kourier-router.lua: |
    local core = require("apisix.core")
    ...

Apply the configmap.

kubectl apply -f knative-kourier-router-plugin.yaml -n apisix

Step 2: Install APISIX

Below is the values you need to update in the values.yaml file to enable the plugin.

apisix:
  customPlugins:
  enabled: true
  luaPath: "/opts/custom_plugins/?.lua"
  plugins:
  - name: knative-kourier-router
    configMap:
      mounts:
        - key: knative-kourier-router.lua
          path: "/opts/custom_plugins/apisix/plugins/knative-kourier-router.lua"
      name: knative-kourier-router-plugin
  plugins:
  - knative-kourier-router

Read more about the values applicable to the helm chart here: https://github.com/apache/apisix-helm-chart/tree/master/charts/apisix

Step 3: Export Schema

Port forward the apisix pod, control port and visit this api via browser http://localhost:9090/v1/schema. You can download the schema file.

Create a configmap using the schema file as follows:

apiVersion: v1
kind: ConfigMap
metadata:
  name: apisix-plugin-schema
data:
  schema.json: |
     {"plugins":{"ext-...

Apply the configmap.

kubectl apply -f apisix-plugin-schema.yaml -n apisix

Restart APISIX to apply the changes.

Step 4: Restart APISIX Dashboard

Below is the values you need to update in the values.yaml file to enable the plugin.

config:
  schema:
    configMap:
      name: apisix-plugin-schema
      key: schema.json

plugins:
- knative-kourier-router

Setup Plugin

Login to APISIX dashboard and start setting up your route.

In the plugins section, you need to configure 2 plugins to enable knative routing.

For the below sample configuration, let's assume the url format is https://example.com/api/v1/<FUNCTION_NAME>/<ACTUAL_URL>.

Above url should be transformed to https://example.com/<ACTUAL_URL> and with host header of value <FUNCTION_NAME>.default. Proxy rewrite plugin will be used to breakdown the url and construct the url required for knative function and knative-kourier-router-plugin will be used to alter the host header.

In proxy rewrite plugin, the extracted function name will be added to x-knative-function custom header to be used by knative-kourier-router-plugin.

Step 1: Add Proxy Rewrite

Enable proxy rewrite and apply below configuration to reformat the url and extract the function name.

headers:
  add:
    x-api-version: $1
    x-knative-function: $2.default
regex_uri:
  - /api/(v[^/]+)/([^/]+)/(.*)
  - /$3

Step 2: Add KNative Kourier Router Plugin

Enable knative-kourier-router-plugin to alter the host header.

header_name: x-knative-function

Note: If the URL contains the namespace default you can remove the .default in proxy rewrite plugin.

Examples

Plugin configuration under a service level can be found in Sample Service

Plugin configuration under a route can be found in Sample Route

Screensots of Route Configuration in APISIX Dashbaord

Proxy rewrite configuration in route definition.

Define API backend server as kourier in route.

Route plugin definition.