Introspection authentication

Configure the OpenID Connect plugin with introspection authentication.

Here’s how introspection auth works:

 
sequenceDiagram
    autonumber
    participant client as Client 
(e.g. mobile app) participant kong as API Gateway
(Kong) participant idp as IdP
(e.g. Keycloak) participant httpbin as Upstream
(upstream service,
e.g. httpbin) activate client activate kong client->>kong: Service with access token deactivate client kong->>kong: load access token activate idp kong->>idp: IdP/introspect with
client credentials and access token deactivate kong idp->>idp: authenticate client
and introspect access token activate kong idp->>kong: return introspection response deactivate idp kong->>kong: verify introspection response activate httpbin kong->>httpbin: request with
access token httpbin->>kong: response deactivate httpbin activate client kong->>client: response deactivate kong deactivate client

In this example, the plugin will only accept a bearer token sent in a header, but you can also set the bearer_token_param_type parameter to body, query, or any combination of these values.

For a complete example of authenticating with a token retrieved through Keycloak’s introspection endpoint, see the tutorial for configuring OpenID Connect with introspection.

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.

Prerequisites

  • A configured identity provider (IdP)

Environment variables

  • ISSUER: The issuer authentication URL for your IdP. For example, if you’re using Keycloak as your IdP, the issuer URL looks like this: http://localhost:8080/realms/example-realm

  • CLIENT_ID: The client ID that the plugin uses when it calls authenticated endpoints of the IdP.

  • CLIENT_SECRET: The client secret needed to connect to your IdP.

Set up the plugin

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