Get started with Datakit

This feature is released as a tech preview (alpha-quality) and should not be depended upon in a production environment.

Enable the WASM engine

In kong.conf, set:

wasm = on

Or export the setting via an environment variable:

KONG_WASM=on

Reload or start Kong Gateway to apply the configuration.

Create a service and a route

decK (YAML)

Admin API

Add the following configuration to a kong.yaml file:

_format_version: "3.0"
services:
- url: http://127.0.0.1:8001/
  name: my-service
  routes:
  - name: my-route
    paths:
    - /
    strip_path: true

Create a service:

  curl -i -X POST http://localhost:8001/services \
 --data "name=my-service" \
 --data "url=http://127.0.0.1:8001/"

Create a route:

  curl -i -X POST http://localhost:8001/services/my-service/routes \
 --data "name=my-route" \
 --data "paths[]=/" \
 --data "strip_path=true"

Enable Datakit

Let’s test out Datakit by combining responses from two third party API calls, then returning directly to the client.

In the following example, replace SERVICE_NAME|ID with my-service, or with your own service name:

Enable on a service

Kong Admin API

Konnect API

Kubernetes

Declarative (YAML)

Konnect Terraform

Make the following request:

curl -X POST http://localhost:8001/services/{serviceName|Id}/plugins \
    --header "accept: application/json" \
    --header "Content-Type: application/json" \
    --data '
    {
  "name": "datakit",
  "config": {
    "debug": true,
    "nodes": [
      {
        "name": "CAT_FACT",
        "type": "call",
        "url": "https://catfact.ninja/fact"
      },
      {
        "name": "DOG_FACT",
        "type": "call",
        "url": "https://dogapi.dog/api/v1/facts"
      },
      {
        "name": "JOIN",
        "type": "jq",
        "inputs": [
          {
            "cat": "CAT_FACT.body"
          },
          {
            "dog": "DOG_FACT.body"
          }
        ],
        "jq": "{\n  \"cat_fact\": $cat.fact,\n  \"dog_fact\": $dog.facts[0]\n}\n"
      },
      {
        "name": "EXIT",
        "type": "exit",
        "inputs": [
          {
            "body": "JOIN"
          }
        ],
        "status": 200
      }
    ]
  }
}
    '

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

Make the following request, substituting your own access token, region, control plane ID, and service ID:

curl -X POST \
https://{us|eu}.api.konghq.com/v2/control-planes/{controlPlaneId}/core-entities/services/{serviceId}/plugins \
    --header "accept: application/json" \
    --header "Content-Type: application/json" \
    --header "Authorization: Bearer TOKEN" \
    --data '{"name":"datakit","config":{"debug":true,"nodes":[{"name":"CAT_FACT","type":"call","url":"https://catfact.ninja/fact"},{"name":"DOG_FACT","type":"call","url":"https://dogapi.dog/api/v1/facts"},{"name":"JOIN","type":"jq","inputs":[{"cat":"CAT_FACT.body"},{"dog":"DOG_FACT.body"}],"jq":"{\n  \"cat_fact\": $cat.fact,\n  \"dog_fact\": $dog.facts[0]\n}\n"},{"name":"EXIT","type":"exit","inputs":[{"body":"JOIN"}],"status":200}]}}'

See the Konnect API reference to learn about region-specific URLs and personal access tokens.

First, create a KongPlugin resource:

echo "
apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: datakit-example
plugin: datakit
config:
  debug: true
  nodes:
  - name: CAT_FACT
    type: call
    url: https://catfact.ninja/fact
  - name: DOG_FACT
    type: call
    url: https://dogapi.dog/api/v1/facts
  - name: JOIN
    type: jq
    inputs:
    - cat: CAT_FACT.body
    - dog: DOG_FACT.body
    jq: |
      {
        "cat_fact": $cat.fact,
        "dog_fact": $dog.facts[0]
      }
  - name: EXIT
    type: exit
    inputs:
    - body: JOIN
    status: 200
" | kubectl apply -f -

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

kubectl annotate service SERVICE_NAME konghq.com/plugins=datakit-example

Replace SERVICE_NAME with the name of the service that this plugin configuration will target. You can see your available ingresses by running kubectl get service.

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: datakit
  service: SERVICE_NAME|ID
  config:
    debug: true
    nodes:
    - name: CAT_FACT
      type: call
      url: https://catfact.ninja/fact
    - name: DOG_FACT
      type: call
      url: https://dogapi.dog/api/v1/facts
    - name: JOIN
      type: jq
      inputs:
      - cat: CAT_FACT.body
      - dog: DOG_FACT.body
      jq: |
        {
          "cat_fact": $cat.fact,
          "dog_fact": $dog.facts[0]
        }
    - name: EXIT
      type: exit
      inputs:
      - body: JOIN
      status: 200

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

Prerequisite: Configure your Personal Access Token

terraform {
  required_providers {
    konnect = {
      source  = "kong/konnect"
    }
  }
}

provider "konnect" {
  personal_access_token = "kpat_YOUR_TOKEN"
  server_url            = "https://us.api.konghq.com/"
}

Add the following to your Terraform configuration to create a Konnect Gateway Plugin:

resource "konnect_gateway_plugin_datakit" "my_datakit" {
  enabled = true

  config = {
    debug = true
    nodes = [
      {
        name = "CAT_FACT"
        type = "call"
        url = "https://catfact.ninja/fact"
      }, 

      {
        name = "DOG_FACT"
        type = "call"
        url = "https://dogapi.dog/api/v1/facts"
      }, 

      {
        name = "JOIN"
        type = "jq"
        inputs = [
          {
            cat = "CAT_FACT.body"
          }, 

          {
            dog = "DOG_FACT.body"
          }        ]
        jq = <<EOF
{
  "cat_fact": $cat.fact,
  "dog_fact": $dog.facts[0]
}
EOF
      }, 

      {
        name = "EXIT"
        type = "exit"
        inputs = [
          {
            body = "JOIN"
          }        ]
        status = 200
      }    ]
  }

  control_plane_id = konnect_gateway_control_plane.my_konnect_cp.id
  service = {
    id = konnect_gateway_service.my_service.id
  }
}

Validate

Access the service via the route my-route to test Datakit:

curl http://locahost:8000/my-route

You should get a 200 response with a random fact from each fact generator called in the config:

HTTP/1.1 200 OK
Connection: keep-alive
Content-Length: 432
Content-Type: application/json
Date: Fri, 06 Dec 2024 18:26:48 GMT
Server: kong/3.9.0.0-enterprise-edition
Via: 1.1 kong/3.9.0.0-enterprise-edition
X-Kong-Proxy-Latency: 744
X-Kong-Request-Id: 878618103ee7137b7c2f914e107cb454
X-Kong-Upstream-Latency: 742

{
    "cat_fact": "The longest living cat on record according to the Guinness Book belongs to the late Creme Puff of Austin, Texas who lived to the ripe old age of 38 years and 3 days!",
    "dog_fact": "Greyhounds can reach a speed of up to 45 miles per hour."
}