Dynamically set upstream based on the authenticated caller with Datakit

This is a Konnect tutorial and requires a Konnect personal access token.

1. Create a new personal access token by opening the Konnect PAT page and selecting Generate Token.

2. Export your token to an environment variable:

   export KONNECT_TOKEN='YOUR_KONNECT_PAT'

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3. Run the quickstart script to automatically provision a Control Plane and Data Plane, and configure your environment:

   curl -Ls https://get.konghq.com/quickstart | bash -s -- -k $KONNECT_TOKEN \
        --deck-output

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   This sets up a Konnect Control Plane named quickstart, provisions a local Data Plane, and prints out the following environment variable exports:

   export DECK_KONNECT_TOKEN=$KONNECT_TOKEN
   export DECK_KONNECT_CONTROL_PLANE_NAME=quickstart
   export KONNECT_CONTROL_PLANE_URL=https://us.api.konghq.com
   export KONNECT_PROXY_URL='http://localhost:8000'

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   Copy and paste these into your terminal to configure your session.

This tutorial requires Kong Gateway Enterprise. If you don’t have Kong Gateway set up yet, you can use the quickstart script with an enterprise license to get an instance of Kong Gateway running almost instantly.

1. Export your license to an environment variable:

    export KONG_LICENSE_DATA='LICENSE-CONTENTS-GO-HERE'

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2. Run the quickstart script:

   curl -Ls https://get.konghq.com/quickstart | bash -s -- -e KONG_LICENSE_DATA 

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   Once Kong Gateway is ready, you will see the following message:

    Kong Gateway Ready

To complete this tutorial, install decK. We recommend keeping decK up to date with the latest version (1.65.1).

decK is a CLI tool for managing Kong Gateway declaratively with state files. This guide uses deck gateway apply, which directly applies entity configuration to your Gateway instance.

You can check your current decK version with deck version.

For this tutorial, you’ll need Kong Gateway entities, like Gateway Services and Routes, pre-configured. These entities are essential for Kong Gateway to function but installing them isn’t the focus of this guide. Follow these steps to pre-configure them:

1. Run the following command:

   echo '
   _format_version: "3.0"
   services:
     - name: example-service
       url: http://httpbin.konghq.com/anything
   routes:
     - name: example-route
       paths:
       - "/anything"
       service:
         name: example-service
       protocols:
       - http
       - https
   ' | deck gateway apply -

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To learn more about entities, you can read our entities documentation.

This tutorial requires an identity provider (IdP). If you don’t have one, you can use Keycloak. The steps will be similar in other standard identity providers.

For this tutorial, you need three clients: one for the OpenID Connect plugin to use when validating tokens, and two representing the API callers that will be routed to different backends.

Install and run Keycloak

1. Install Keycloak (version 26 or later) on your platform.

   For example, you can use the Keycloak Docker image. The following command attaches Keycloak to the same network as Kong Gateway so that the OIDC plugin can reach it. Open a new session in your terminal and run:

   docker run -p 127.0.0.1:8080:8080 \
     --name keycloak \
     --network kong-quickstart-net \
     -e KC_BOOTSTRAP_ADMIN_USERNAME=admin \
     -e KC_BOOTSTRAP_ADMIN_PASSWORD=admin \
     -e KC_HOSTNAME=http://localhost:8080 \
     quay.io/keycloak/keycloak start-dev

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   The KC_HOSTNAME=http://localhost:8080 parameter ensures Keycloak always uses localhost:8080 as its token issuer regardless of which URL it’s accessed through. This is required because Kong Gateway runs inside Docker and accesses Keycloak via the container name keycloak:8080, but the iss claim in issued tokens must use localhost:8080 for the plugin to recognize them.

2. Export your issuer URL, JWKS endpoint, and Keycloak host to environment variables. For example, using Docker and the default master realm:

   export DECK_ISSUER='http://localhost:8080/realms/master'
   export DECK_JWKS_ENDPOINT='http://keycloak:8080/realms/master/protocol/openid-connect/certs'
   export KEYCLOAK_HOST='localhost'

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   Because we’re using Docker for this demo, we must configure a few networking parameters:

   • DECK_ISSUER and KEYCLOAK_HOST use localhost because that’s how you access Keycloak from your machine.
   • DECK_JWKS_ENDPOINT uses the container name keycloak because Kong Gateway runs inside Docker and reaches Keycloak over the shared kong-quickstart-net network.

   In your own setup, especially running outside of a container, you may not need DECK_JWKS_ENDPOINT.

3. Open the admin console at default URL http://localhost:8080/admin/master/console/ and sign in with your username (admin) and password (admin).

Create the plugin client

This client is used by the OpenID Connect plugin to connect to Keycloak for token validation.

1. In the sidebar, open Clients, then click Create client.
2. Configure the client:

1. Open the Credentials tab.
2. Set Client Authenticator to Client ID and Secret.

3. Copy the Client Secret and export it along with the client ID:

   export DECK_CLIENT_ID='kong'
   export DECK_CLIENT_SECRET='YOUR-KONG-CLIENT-SECRET'

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Create the caller clients

These clients represent the API callers. Each one authenticates to Keycloak with the client credentials grant. The client_id claim in each token is what Datakit uses to select the upstream.

Create the first caller client:

1. In the sidebar, open Clients, then click Create client.
2. Configure the client:

1. Open the Credentials tab.
2. Set Client Authenticator to Client ID and Secret.

3. Copy the Client Secret and export it:

   export CALLER_A_SECRET='YOUR-CALLER-A-SECRET'

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Create the second caller client:

1. In the sidebar, open Clients, then click Create client.
2. Configure the client:

1. Open the Credentials tab.
2. Set Client Authenticator to Client ID and Secret.

3. Copy the Client Secret and export it:

   export CALLER_B_SECRET='YOUR-CALLER-B-SECRET'

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