Configure OpenID Connect with JWT authentication

Uses: Kong Gateway decK
TL;DR

Using the OpenID Connect plugin, set up the JWT auth workflow to connect to an identity provider (IdP) and use the validated token to access the upstream service.

Prerequisites

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.

Enable the OpenID Connect plugin with JWT authentication

Using the Keycloak and Kong Gateway configuration from the prerequisites, set up an instance of the OpenID Connect plugin with bearer authentication. The stateless JWT Access Token authentication is named bearer in the OpenID Connect plugin.

We’re also enabling the password grant so that you can test retrieving the bearer auth token.

Enable the OpenID Connect plugin on the example-service Service:

echo '
_format_version: "3.0"
plugins:
  - name: openid-connect
    service: example-service
    config:
      issuer: "${{ env "DECK_ISSUER" }}"
      client_id:
      - "${{ env "DECK_CLIENT_ID" }}"
      client_secret:
      - "${{ env "DECK_CLIENT_SECRET" }}"
      client_auth:
      - client_secret_post
      auth_methods:
      - bearer
      - password
      bearer_token_param_type:
      - query
' | deck gateway apply -
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In this example:

  • issuer, client ID, client secret, and client auth: Settings that connect the plugin to your IdP (in this case, the sample Keycloak app).
  • auth_methods: Specifies that the plugin should use bearer authentication and the password grant.
  • bearer_token_param_type: Restricts token lookup to the query string only.

Note: Setting config.client_auth to client_secret_post lets you easily test the connection to your IdP, but we recommend using a more secure auth method in production. You can use any of the supported client auth methods.

Retrieve the bearer token

Check that you can recover the token by sending a request to the Service with the basic authentication credentials created in the prerequisites:

curl -i -X GET "$KONNECT_PROXY_URL/anything" \
     -u alex:doe
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You’ll see an Authorization header with your access token in the response.

When passing the token in a query string, you don’t need to include the Bearer portion of the token. Copy the token without Bearer, and export the value of the header to an environment variable:

export TOKEN='YOUR_TOKEN_WITHOUT_BEARER_PREFIX'
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Validate the token

Now, validate the setup by accessing the example-route Route and passing the bearer token in the query string:

curl -i -X GET "$KONNECT_PROXY_URL/anything?access_token=$TOKEN"
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If Kong Gateway successfully authenticates with Keycloak, you’ll see a 200 response with your bearer token in the Authorization header.

If you make another request using the same credentials, you’ll see that Kong Gateway adds less latency to the request because it has cached the token endpoint call to Keycloak:

X-Kong-Proxy-Latency: 25

Cleanup

If you created a new control plane and want to conserve your free trial credits or avoid unnecessary charges, delete the new control plane used in this tutorial.

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