Quarkus - Using OpenID Connect Multi-Tenancy

This guide demonstrates how your OpenID Connect application can support multi-tenancy so that you can serve multiple tenants from a single application. Tenants can be distinct realms or security domains within the same OpenID Provider or even distinct OpenID Providers.

When serving multiple customers from the same application (e.g.: SaaS), each customer is a tenant. By enabling multi-tenancy support to your applications you are allowed to also support distinct authentication policies for each tenant even though if that means authenticating against different OpenID Providers, such as Keycloak and Google.

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 application which offers a single land page:

  • /{tenant}

The land page is served by a JAX-RS Resource and shows information obtained from the OpenID Provider about the authenticated user and the current tenant.

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-multi-tenancy 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-multi-tenancy \
    -Dextensions="oidc, resteasy-jsonb"
cd security-openid-connect-multi-tenancy

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 /{tenant} endpoint. As you can see from the source code below it is just a regular JAX-RS resource:

package org.acme.quickstart.oidc;

import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;

import org.eclipse.microprofile.jwt.JsonWebToken;

import io.quarkus.oidc.IdToken;

@Path("/{tenant}")
public class HomeResource {

    /**
     * Injection point for the ID Token issued by the OpenID Connect Provider
     */
    @Inject
    @IdToken
    JsonWebToken idToken;

    /**
     * Returns the tokens available to the application. This endpoint exists only for demonstration purposes, you should not
     * expose these tokens in a real application.
     *
     * @return the landing page HTML
     */
    @GET
    public String getHome() {
        StringBuilder response = new StringBuilder().append("<html>").append("<body>");

        response.append("<h2>Welcome, ").append(this.idToken.getClaim("email").toString()).append("</h2>\n");
        response.append("<h3>You are accessing the application within tenant <b>").append(idToken.getIssuer()).append(" boundaries</b></h3>");

        return response.append("</body>").append("</html>").toString();
    }
}

In order to resolve the tenant from incoming requests and map it to a specific quarkus-oidc tenant configuration in application.properties, you need to create an implementation for the io.quarkus.oidc.TenantResolver interface.

package org.acme.quickstart.oidc;

import javax.enterprise.context.ApplicationScoped;

import io.quarkus.oidc.TenantResolver;
import io.vertx.ext.web.RoutingContext;

@ApplicationScoped
public class CustomTenantResolver implements TenantResolver {

    @Override
    public String resolve(RoutingContext context) {
        String path = context.request().path();
        String[] parts = path.split("/");

        if (parts.length == 0) {
            // resolve to default tenant configuration
            return null;
        }

        return parts[1];
    }
}

From the implementation above, tenants are resolved from the request path so that in case no tenant could be inferred, null is returned to indicate that the default tenant configuration should be used.

Configuring the application

# Default Tenant Configuration
quarkus.oidc.auth-server-url=http://localhost:8180/auth/realms/quarkus
quarkus.oidc.client-id=multi-tenant-client
quarkus.oidc.application-type=web-app

# Tenant A Configuration
quarkus.oidc.tenant-a.auth-server-url=http://localhost:8180/auth/realms/tenant-a
quarkus.oidc.tenant-a.client-id=multi-tenant-client
quarkus.oidc.tenant-a.application-type=web-app

# HTTP Security Configuration
quarkus.http.auth.permission.authenticated.paths=/*
quarkus.http.auth.permission.authenticated.policy=authenticated

The first configuration is the default tenant configuration that should be used when the tenant can not be inferred from the request. This configuration is using a Keycloak instance to authenticate users.

The second configuration is the configuration that will be used when an incoming request is mapped to the tenant tenant-a.

Note that both configurations map to the same Keycloak server instance while using distinct realms.

You can define multiple tenants in your configuration file, just make sure they have a unique alias so that you can map them properly when resolving a tenant from your TenantResolver implementation.

Google OpenID Provider Configuration

In order to set-up the tenant-a configuration to use Google OpenID Provider, you need to create a project as described here.

Once you create the project and have your project’s client_id and client_secret, you can try to configure a tenant as follows:

# Tenant configuration using Google OpenID Provider
quarkus.oidc.tenant-b.auth-server-url=https://accounts.google.com
quarkus.oidc.tenant-b.application-type=web-app
quarkus.oidc.tenant-b.client-id={GOOGLE_CLIENT_ID}
quarkus.oidc.tenant-b.credentials.secret={GOOGLE_CLIENT_SECRET}
quarkus.oidc.tenant-b.token.issuer=https://accounts.google.com
quarkus.oidc.tenant-b.authentication.scopes=email,profile,openid

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.

Now, follow the steps below to import the realms for the two tenants:

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

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-multi-tenancy-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-multi-tenancy-quickstart-runner

Testing the Application

To test the application, you should open your browser and access the following URL:

If everything is working as expected, you should be redirected to the Keycloak server to authenticate. Note that the requested path defines a default tenant which we don’t have mapped in the configuration file. In this case, the default configuration will be used.

In order to authenticate to the application you should type the following credentials when at the Keycloak login page:

  • Username: alice

  • Password: alice

After clicking the Login button you should be redirected back to the application.

If you try now to access the application at the following URL:

You should be redirected again to the login page at Keycloak. However, now you are going to authenticate using a different realm.

In both cases, if the user is successfully authenticated, the landing page will show the user’s name and e-mail. Even though user alice exists in both tenants, for the application they are distinct users belonging to different realms/tenants.

Programmatically Resolving Tenants Configuration

If you need a more dynamic configuration for the different tenants you want to support and don’t want to end up with multiple entries in your configuration file, you can use the io.quarkus.oidc.TenantConfigResolver.

This interface allows you to dynamically create tenant configurations at runtime:

package io.quarkus.it.keycloak;

import javax.enterprise.context.ApplicationScoped;

import io.quarkus.oidc.TenantConfigResolver;
import io.quarkus.oidc.runtime.OidcTenantConfig;
import io.vertx.ext.web.RoutingContext;

@ApplicationScoped
public class CustomTenantConfigResolver implements TenantConfigResolver {

    @Override
    public OidcTenantConfig resolve(RoutingContext context) {
        String path = context.request().path();
        String[] parts = path.split("/");

        if (parts.length == 0) {
            // resolve to default tenant configuration
            return null;
        }

        if ("tenant-c".equals(parts[1])) {
            OidcTenantConfig config = new OidcTenantConfig();

            config.setTenantId("tenant-c");
            config.setAuthServerUrl("http://localhost:8180/auth/realms/tenant-c");
            config.setClientId("multi-tenant-client");
            OidcTenantConfig.Credentials credentials = new OidcTenantConfig.Credentials();

            credentials.setSecret("my-secret");

            config.setCredentials(credentials);

            // any other setting support by the quarkus-oidc extension

            return config;
        }

        // resolve to default tenant configuration
        return null;
    }
}

The OidcTenantConfig returned from this method is the same used to parse the oidc namespace configuration from the application.properties. You can populate it using any of the settings supported by the quarkus-oidc extension.

Disabling Tenant Configurations

Custom TenantResolver and TenantConfigResolver implementations may return null if no tenant can be inferred from the current request and a fallback to the default tenant configuration is required.

If it is expected that the custom resolvers will always infer a tenant then the default tenant configuration is not needed. One can disable it with the quarkus.oidc.tenant-enabled=false setting.

Note that tenant specific configurations can also be disabled, for example: quarkus.oidc.tenant-a.tenant-enabled=false.

Configuration Reference