Integrating Immutant and Keycloak

A computer scientist working in open source towards a more hopeful future.

Posted on 2014-07-25, around 6 minutes of reading.

In my past two posts, we took a surface level look at Immutant then took a look at deploying immutant applications to the Wildfly application server. This time, we'll take a look at how to integrate Keycloak with an Immutant app, again using Docker heavily.

If you haven't read the previous few articles, it might be useful to give them a quick glance over.

Keycloak

Erecting Keycloak

Keycloak is an integrated Single-Sign-On and Identity Management platform from the fine folks of JBoss. A Docker image of Keycloak is available here, just like Immutant, Wildfly, and a few others.

To pull the Keycloak image:

docker pull jboss/keycloak

Then, to erect the container (Source):

docker run -it --name keycloak -p 8080:8080 -p 9090:9090 jboss/keycloak

Use the -d flag to daemonize the service so it doesn't die with the tty. You can check the logs later with docker logs -f keycloak

Finally, you should be able to browse to http://localhost:8080/ and see the friendly Wildfly logo and welcome screen. Visiting http://localhost:8080/auth/ should yield a Keycloak welcome screen.

Getting into Keycloak

Visiting http://localhost:8080/auth/admin/ should bring you to a very blue login screen. The Keycloak docker image starts with a pre-created admin account for you to log in with.

Username: admin

Password: admin

After logging in, Keycloak should prompt for a password change.

Creating an Application

Browse to the Applications menu and hit the blue Add Application button. For this exploration, I'm creating a learning application.

Name: learning

Enabled: ON

Access Type: confidential

Redirect URI: http://localhost:8081/*

After hitting save, you'll have the opportunity to add more information. For this exploration, we don't need to add any more information here.

Visiting the Roles tab at the top, hit Add Role and create a pair of roles:

There are several other tabs which contain many more interesting configuration options, but we'll leave these alone for now.

Creating Some Users

In our exploration, we'll utilize both of the scopes above to see how to allow different roles to access different parts of the site.

Browse over to the Users menu. Beside the search box, hit View all Users. You should see admin already created. Create a user user, the rest of the information you can use anything, or nothing.

Going back to the user listing. Select the admin user and go to the Role Mappings tab. At the bottom in "Application Roles" select learning from the dropdown. Add the admin role for the admin user. Then, repeat the steps for the user user, but only assign them the user role, not admin.

What does this all mean? The admin user should be able to access every page the admin role can. The user user should not be able to access the admin role's pages.

Immutant

Setting Up the Immutant Application

Start up a new lein project with:

lein new app learning

Your learning/project.clj needs to be modified to look similar to this:

(defproject learning "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "MPL"
            :url "http://choosealicense.com/licenses/mpl-2.0/"}
  :dependencies [[org.clojure/clojure "1.6.0"]
                 [org.immutant/immutant "2.x.incremental.191"]
                 [compojure "1.1.8"]]
  :repositories [["Immutant incremental builds"
                  "http://downloads.immutant.org/incremental/"]]
  :plugins [[lein-immutant "2.0.0-SNAPSHOT"]]
  :main ^:skip-aot learning.core
  :target-path "target/%s"
  :profiles {:uberjar {:aot :all}}
  ; Plugin configuration.
  :ring {:handler learning.core/app}
  :immutant {
     :war {
        :dev? false
        :resource-paths ["resources"]
        :nrepl {
          :port 8888
          :start? true}}})

Now change your learning/src/learning/core.clj file to contain the following:

(ns learning.core
  (:use compojure.core)
  (:require [compojure.route       :as route]
            [immutant.web          :as web]
            [immutant.web.servlet  :as servlet])
  (:gen-class))


(defn get-token
  "Gets the session for the user"
  [request]
  (let [{servlet-request :servlet-request} request
        security-context (.getAttribute servlet-request "org.keycloak.KeycloakSecurityContext")
        id-token (.getIdToken security-context)]
    id-token))

(defn show-profile
  "Shows the profile of the user"
  [request]
  (try
    (let [token (get-token request)]
      ; The token is a Java Object, don't expect more then a reference.
      (str "<p>Token is: <pre>" token "</pre></p>"
           ; This should show the users name.
           ; Reference: https://docs.jboss.org/keycloak/docs/1.0-beta-3/javadocs/org/keycloak/representations/IDToken.html
           "<p>User is: <pre>" (.getPreferredUsername token) "</pre></p>"))
    (catch Exception e
      ; There is no token.
      (str "<p>No user found.</p><pre>" e "</pre>"))))

(defn test-handler
  "A very versatile test route handler"
  ; Handled different arities.
  ([request base]
   (str "<h1>Base: " base "</h1>"
        "<p>" (show-profile request) "</p>"))
  ([request base sub]
   (str "<h1>Base: " base " Sub: " sub "</h1>"
        "<p>" (show-profile request) "</p>"))
  ([request base sub subsub]
   (str "<h1>Base: " base " Sub: " sub " Subsub: " subsub "</h1>"
        "<p>" (show-profile request) "</p>")))

(defroutes app
  "The router."
  ; Logout
  ; Doesn't currently work: https://issues.jboss.org/browse/KEYCLOAK-478
  (GET "/logout" [:as request]
    (let [{servlet-request :servlet-request} request]
      (.logout servlet-request)
      (str "Logged out")))
  ; Rest of the routes.
  (GET "/" [:as request]
       (test-handler request "/"))
  (GET "/:base" [base :as request]
       (test-handler request base))
  (GET "/:base/:sub" [base sub :as request]
       (test-handler request base sub))
  (GET "/:base/:sub/:subsub" [base sub subsub :as request]
       (test-handler request base sub subsub))
  (route/not-found "<h1>Page not found</h1>"))

(defn -main
  "Start the server"
  [& args]
  ; Start the server.
  (web/run (servlet/create-servlet app) :port 8081))

The get-token function returns an object that you can run things like (.getPreferredUsername token). This documents the different methods you can use.

Planning the Routes

The routes are specifically very, very general so that we can test various routes. In our exploration we'll be paying attention to the following routes:

The routes in our code above covers much, much more then those, but you can play with those on your own.

Integrating Keycloak

Keycloak's User Guide specifies how to secure the application via the web.xml. If you're familiar with JBoss (I'm not) this is apparently a fairly standard way of securing the application.

However, Immutant does not currently provide an easy way to modify the web.xml in the war files it builds. Thankfully, since a war is a jar, and a jar is a zip, we can just add it in after.

First, lets make a folder for this type of data in /learning/resources.

mkdir resources/WEB-INF

Then, create a learning/resources/WEB-INF/web.xml with the following XML:

<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
	<distributable/>
	<listener>
		<listener-class>org.projectodd.wunderboss.wildfly.ServletListener</listener-class>
	</listener>

	<!-- Anyone -->
	<security-constraint>
		<web-resource-collection>
			<web-resource-name>test</web-resource-name>
			<url-pattern>/test</url-pattern>
			<url-pattern>/test/*</url-pattern>
		</web-resource-collection>
	</security-constraint>

	<!-- Users and Admins -->
	<security-constraint>
		<auth-constraint>
			<role-name>user</role-name>
			<role-name>admin</role-name>
		</auth-constraint>
		<web-resource-collection>
			<web-resource-name>locked</web-resource-name>
			<url-pattern>/locked</url-pattern>
			<!-- Wildcard. Covers /locked/foo, /locked/foo/bar, etc -->
			<url-pattern>/locked/*</url-pattern>
		</web-resource-collection>
	</security-constraint>

	<!-- Admins -->
	<security-constraint>
		<auth-constraint>
			<role-name>admin</role-name>
		</auth-constraint>
		<web-resource-collection>
			<web-resource-name>admin</web-resource-name>
			<url-pattern>/admin</url-pattern>
			<!-- Wildcard. Covers /admin/foo, /admin/foo/bar, etc -->
			<url-pattern>/admin/*</url-pattern>
		</web-resource-collection>
	</security-constraint>

	<!-- Logout Route -->
	<security-constraint>
		<auth-constraint>
			<role-name>admin</role-name>
			<role-name>user</role-name>
		</auth-constraint>
		<web-resource-collection>
			<web-resource-name>logout</web-resource-name>
			<url-pattern>/logout</url-pattern>
		</web-resource-collection>
	</security-constraint>

	<!-- Keycloak conf -->
	<login-config>
		<auth-method>KEYCLOAK</auth-method>
		<realm-name>master</realm-name>
	</login-config>

</web-app>

Now, navigate back to your Keycloak container, log in, and go to the Applications menu, hit learning, and go to the Installation tab. Select the keycloak.json from the dropdown. Finally, Download the output and save it as learning/WEB-INF/keycloak.json.

Building the container

Since we'll be using a Docker container for the application, create a learning/Dockerfile with the following:

FROM jboss/keycloak-adapter-wildfly
RUN /opt/wildfly/bin/add-user.sh admin hunter2 --silent
ADD target/base+system+user+dev/learning.war /opt/wildfly/standalone/deployments/ROOT.war

Then a learning/Makefile to (optionally) make things a bit smoother:

all:
	docker rm -f immut-test || true
	docker rmi immut-learning || true
	lein immutant war
	docker build -t immut-learning .

run:
	docker run --name immut-test --rm -t -i -p 127.0.0.1:8081:8080 -p 127.0.0.1:9991:9990 --link keycloak:auth immut-learning

Just one more thing: Due to the linking between containers, you may need to add a line to your /etc/hosts so that the application will appropriately talk to the Keycloak server. The line should look like this:

127.0.0.1 auth

Then, edit your keycloak.json and set the auth-server-url:

"auth-server-url": "http://auth:8080/auth",

Running

You should now be able to build and start the application with:

make && make run

After waiting for boot, browsing to http://localhost:8081/test should yield you a page that says, roughly:

Base = "test"

No user found.

java.lang.NullPointerException

Exploring

User routes

Now, try visiting http://localhost:8081/locked. You should get redirected to the familiar Keycloak login screen. Log in with the user account. You should see something roughly like:

Base = "locked Sub: test"

Token is:

org.keycloak.representations.IDToken@7f55bb4f

User is:

user

Fantastic. Now, try navigating to the admin route at http://localhost:8081/admin. You should see the helpful Forbidden error. This is exactly what we want!

Admin routes

In order to change accounts, you, unfortunately, can't browse to http://localhost:8081/logout. This seems to be a bug to be squashed in the next version of Keycloak (Bug), but I'll leave it here for posterity. For now, navigate to http://localhost:8080/auth, log in as admin, navigate to the Sessions and Tokens and click the blue Logout All button.

Browse back to http://localhost:8081/admin and log in as admin. You should see:

Base = "admin"

Token is:

org.keycloak.representations.IDToken@4a8ca873

User is:

admin

You should also be able to hit all other routes as the admin. Be sure to explore Keycloak, as it has many features regarding roles, permissions, and other things not covered here.

Special thanks to all the folks on #immutant, especially bbrowning, tcrawley, and jcrossley3 for their help!

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