Quarkus - Using OpenID Connect to Protect Service Applications

This guide demonstrates how your Quarkus application can use an OpenID Connect Adapter to protect your JAX-RS applications using bearer token authorization, where these tokens are issued by OpenId Connect and OAuth 2.0 compliant Authorization Servers such as Keycloak.

Bearer Token Authorization is the process of authorizing HTTP requests based on the existence and validity of a bearer token representing a subject and his access context, where the token provides valuable information to determine the subject of the call as well whether or not a HTTP resource can be accessed.

We are going to give you a guideline on how to use OpenId Connect and OAuth 2.0 in your JAX-RS applications using the Quarkus OpenID Connect Extension.

This technology is considered preview.

In preview, backward compatibility and presence in the ecosystem is not guaranteed. Specific improvements might require to change configuration or APIs and plans to become stable are under way. Feedback is welcome on our mailing list or as issues in our GitHub issue tracker.

For a full list of possible extension statuses, check our FAQ entry.

Prerequisites

To complete this guide, you need:

  • less than 15 minutes

  • an IDE

  • JDK 1.8+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.6.2+

  • jq tool

  • Docker

Architecture

In this example, we build a very simple microservice which offers three endpoints:

  • /api/users/me

  • /api/admin

These endpoints are protected and can only be accessed if a client is sending a bearer token along with the request, which must be valid (e.g.: signature, expiration and audience) and trusted by the microservice.

The bearer token is issued by a Keycloak Server and represents the subject to which the token was issued for. For being an OAuth 2.0 Authorization Server, the token also references the client acting on behalf of the user.

The /api/users/me endpoint can be accessed by any user with a valid token. As a response, it returns a JSON document with details about the user where these details are obtained from the information carried on the token.

The /api/admin endpoint is protected with RBAC (Role-Based Access Control) where only users granted with the admin role can access. At this endpoint, we use the @RolesAllowed annotation to declaratively enforce the access constraint.

Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The solution is located in the security-openid-connect-quickstart directory.

Creating the Maven Project

First, we need a new project. Create a new project with the following command:

mvn io.quarkus:quarkus-maven-plugin:1.6.0.Final:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=security-openid-connect-quickstart \
    -Dextensions="oidc, resteasy-jsonb"
cd security-openid-connect-quickstart

This command generates a Maven project, importing the keycloak extension which is an implementation of a Keycloak Adapter for Quarkus applications and provides all the necessary capabilities to integrate with a Keycloak Server and perform bearer token authorization.

If you already have your Quarkus project configured, you can add the oidc extension to your project by running the following command in your project base directory:

./mvnw quarkus:add-extension -Dextensions="oidc"

This will add the following to your pom.xml:

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-oidc</artifactId>
</dependency>

Writing the application

Let’s start by implementing the /api/users/me endpoint. As you can see from the source code below it is just a regular JAX-RS resource:

package org.acme.security.openid.connect;

import javax.annotation.security.RolesAllowed;
import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import org.jboss.resteasy.annotations.cache.NoCache;
import io.quarkus.security.identity.SecurityIdentity;

@Path("/api/users")
public class UsersResource {

    @Inject
    SecurityIdentity securityIdentity;

    @GET
    @Path("/me")
    @RolesAllowed("user")
    @Produces(MediaType.APPLICATION_JSON)
    @NoCache
    public User me() {
        return new User(securityIdentity);
    }

    public static class User {

        private final String userName;

        User(SecurityIdentity securityIdentity) {
            this.userName = securityIdentity.getPrincipal().getName();
        }

        public String getUserName() {
            return userName;
        }
    }
}

The source code for the /api/admin endpoint is also very simple. The main difference here is that we are using a @RolesAllowed annotation to make sure that only users granted with the admin role can access the endpoint:

package org.acme.security.openid.connect;

import javax.annotation.security.RolesAllowed;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("/api/admin")
public class AdminResource {

    @GET
    @RolesAllowed("admin")
    @Produces(MediaType.TEXT_PLAIN)
    public String admin() {
        return "granted";
    }
}

Injection of the SecurityIdentity is supported in both @RequestScoped and @ApplicationScoped contexts.

Accessing JWT claims

If you need to access JsonWebToken claims, you may simply inject the token itself:

package org.acme.security.openid.connect;

import org.eclipse.microprofile.jwt.JsonWebToken;

import javax.annotation.security.RolesAllowed;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("/api/admin")
public class AdminResource {

    @Inject
    JsonWebToken jwt;

    @GET
    @RolesAllowed("admin")
    @Produces(MediaType.TEXT_PLAIN)
    public String admin() {
        return "Access for subject " + jwt.getSubject() + " is granted";
    }
}

Injection of the JsonWebToken is supported in both @RequestScoped and @ApplicationScoped contexts.

Configuring the application

The OpenID Connect extension allows you to define the adapter configuration using the application.properties file which should be located at the src/main/resources directory.

Configuring using the application.properties file

Example configuration:

quarkus.oidc.auth-server-url=http://localhost:8180/auth/realms/quarkus
quarkus.oidc.client-id=backend-service

Configuring CORS

If you plan to consume this application from another application running on a different domain, you will need to configure CORS (Cross-Origin Resource Sharing). Please read the HTTP CORS documentation for more details.

Starting and Configuring the Keycloak Server

To start a Keycloak Server you can use Docker and just run the following command:

docker run --name keycloak -e KEYCLOAK_USER=admin -e KEYCLOAK_PASSWORD=admin -p 8180:8080 {keycloak-docker-image}

You should be able to access your Keycloak Server at localhost:8180/auth.

Log in as the admin user to access the Keycloak Administration Console. Username should be admin and password admin.

Import the realm configuration file to create a new realm. For more details, see the Keycloak documentation about how to create a new realm.

If you want to use the Keycloak Admin Client to configure your server from your application you need to include the quarkus-keycloak-admin-client extension.

Running and Using the Application

Running in Developer Mode

To run the microservice in dev mode, use ./mvnw clean compile quarkus:dev.

Running in JVM Mode

When you’re done playing with "dev-mode" you can run it as a standard Java application.

First compile it:

./mvnw package

Then run it:

java -jar ./target/security-openid-connect-quickstart-runner.jar

Running in Native Mode

This same demo can be compiled into native code: no modifications required.

This implies that you no longer need to install a JVM on your production environment, as the runtime technology is included in the produced binary, and optimized to run with minimal resource overhead.

Compilation will take a bit longer, so this step is disabled by default; let’s build again by enabling the native profile:

./mvnw package -Pnative

After getting a cup of coffee, you’ll be able to run this binary directly:

./target/security-openid-connect-quickstart-runner

Testing the Application

The application is using bearer token authorization and the first thing to do is obtain an access token from the Keycloak Server in order to access the application resources:

export access_token=$(\
    curl -X POST http://localhost:8180/auth/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=alice&password=alice&grant_type=password' | jq --raw-output '.access_token' \
 )

The example above obtains an access token for user alice.

Any user is allowed to access the http://localhost:8080/api/users/me endpoint which basically returns a JSON payload with details about the user.

curl -v -X GET \
  http://localhost:8080/api/users/me \
  -H "Authorization: Bearer "$access_token

The http://localhost:8080/api/admin endpoint can only be accessed by users with the admin role. If you try to access this endpoint with the previously issued access token, you should get a 403 response from the server.

curl -v -X GET \
   http://localhost:8080/api/admin \
   -H "Authorization: Bearer "$access_token

In order to access the admin endpoint you should obtain a token for the admin user:

export access_token=$(\
    curl -X POST http://localhost:8180/auth/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=admin&password=admin&grant_type=password' | jq --raw-output '.access_token' \
 )