Configure OpenID Connect with Consumer authorization

Uses: Kong Gateway deck
TL;DR

Use the OpenID Connect plugin with Consumers for authorization and dynamically map claim values to Consumers. This only allows IdP users that have a matching Consumer in Kong Gateway to access your Services, giving you more control over which clients have access to Kong Gateway.

Set up any type of authentication (the password grant, in this guide) and enable Consumer mapping by setting a claim to map to.

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

Using the Keycloak and Kong Gateway configuration from the prerequisites, set up an instance of the OpenID Connect plugin. In this example, we’re using the simple password grant with the preferred_username Consumer claim.

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:
      - password
      consumer_claim:
      - preferred_username
      consumer_by:
      - username
' | 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 the password grant, for easy testing.
  • consumer_claim and consumer_by : Looks for a preferred_username in the token payload and maps it to the Consumer entity by the entity’s username value.

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.

Create a Consumer

First, let’s try to access the Service without a matching Consumer. Request 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 should get a 403 Forbidden error code, which means the Service is protected by authentication.

Create a Consumer with a username that matches the user in your IdP, in this case alex:

echo '
_format_version: "3.0"
consumers:
  - username: alex
' | deck gateway apply -
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Verify Consumer authorization

Now, your configured Consumer can access the example-route Route by using their username and password in username:password format:

 curl -i -X GET "$KONNECT_PROXY_URL/anything" \
     -u alex:doe
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This time, you should get a 200 response. The OIDC plugin decodes the token it receives from the IdP, finds the preferred_username value, and maps it to our Consumer alex.

In the response, you’ll see that the plugin added the X-Consumer-Id and X-Consumer-Username as request headers, and returned an Authorization bearer token:

"Authorization": "Bearer abcxyz...",
"X-Consumer-Id": "some-uuid",
"X-Consumer-Username": "alex"

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.

FAQs

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