Camunda Platform 7 - Keycloak Identity Provider Plugin

Keycloak™ (https://www.keycloak.org/) is an Open Source Identity and Access Management platform including advanced features such as User Federation, Identity Brokering and Social Login.

Camunda™ (https://camunda.com/) Platform 7 is perfectly suited to carry out BPM projects in the cloud. Identity management in the cloud, however, often differs from classical approaches. Camunda already provides a generic sample for Single Sign On when using Spring Boot. See https://github.com/camunda-consulting/code/tree/master/snippets/springboot-security-sso. Specific instructions on how to use Spring Boots OAuth2 SSO in combination with this Keycloak Identity Provider Plugin can be found below.

Why this plugin? SSO is sufficient in case you only want authentication but have no further advanced security roles. If one needs to use Camundas IdentityService APIs or wants to see actual Users and Groups show up in Cockpit, a custom IdentityProvider needs to be implemented as well.

This plugin provides the basis for using Keycloak as Identity Management solution and will provide a ReadOnlyIdentityProvider. What you will get is a fully integrated solution for using Keycloak as an Identity Provider in Camunda receiving users and groups from Keycloak. The authorization of these users and groups for Camunda resources itself remains within Camunda. This plugin allows the usage of Keycloak as Identity Provider even without SSO.

Beware: in case you want to use Keycloak's advanced login capabilities for social connections you must configure SSO as well. Password grant exchanges are only supported for Keycloak's internally managed users and users of an LDAP / Keberos User federation. Hence without SSO you will only be able to login with users managed by such connections.

Current version: 7.21.1
Latest tests with: Keycloak 24.0.3, 19.0.3-legacy, Camunda 7.21.0, 7.21.0-ee

Features

Changes in version 7.21.1

• Upgrade to Camunda Platform 7.21.0
• New configuration flag enforceSubgroupsInGroupQuery for enforcing subgroups in query results when using Keycloak >= 23.0.0

Changes in version 7.20.1

With version 7.20.0 Camunda Platform 7 switched to Spring Boot 3.1, JakartaEE 10 and a JDK 17 baseline. The Keycloak Identity Provider Plugin has been updated to support the new baseline versions of it's major dependencies.

• Upgrade to Camunda Platform 7.20.0
• Upgrade to Apache HttpComponents HttpClient 5
• Upgrade to Spring Boot 3.1.x
• Updated samples to Spring Security 6.1

Changes in version 7.19.0

• Updated samples to Camunda Platform 7.19 and Keycloak 21.1

New in version 7.18.0

• Fixed a bug for userId's containing a plus sign.
• Updated samples to Camunda Platform 7.18 and Keycloak >= 18
• Alternative for client side JWT authentication in Camunda Cockpit (incubation status)

Changes in Version 7.17.0

• Renamed the extension from camunda-bpm-identity-keycloak to camunda-platform-7-keycloak
• Updated samples to Camunda Platform 7.17
• Introduced new version which reflects the Camunda Version used in samples and tests.

New in Version 2.2.3:

• Optional Keycloak Login Cache - helps you to minimize password check requests to Keycloak and thus improve performance. Not applicable in SSO scenarios, but useful e.g. when using External Task Clients with Basic Auth.

New in Version 2.2.2:

• Optimized user / group queries when using single items in userIdIn(...) / groupIdIn(...) selections

New in Version 2.2.1:

• Fixed a bug where "like" filters in combination with missing Keycloak attributes (e.g. users without email) may cause a NullPointerException

New in Version 2.2.0:

• Optional Keycloak Query Cache - helps you to minimize requests to Keycloak and thus improve performance.
• Minor optimization of refresh token handling in case it is missing at all.

New in Version 2.1.0:

• Auto retry with refreshed new token in case of Keycloak HTTP 401 responses (more stability in case of misconfigurations).

New in Version 2.0.0:

• Support for Camunda Platform 7 Run
• New options proxyUri, proxyUser, proxyPassword for optional proxy support.
• Usage of com.google.code.gson for JSON (de)serialization.
• Further internal refactorings and preparations for future enhancements.

New in Version 1.5.0:

• New option maxResultSize for configuring the maximum result size of queries against the Keycloak REST API.

New in Version 1.4.0:

• Corrected rare problems with group queries of a single user in case the Keycloak Client name is similar to this username and config property useUsernameAsCamundaUserId=true

New in Version 1.3.0:

• Provided additional fat camunda-platform-7-keycloak-all.jar including transitive dependencies for easier installation e.g. on Apache Tomcat distribution with shared engine.

New in Version 1.2.0:

• Optimized and correct searches in Keycloak mass data
• Add missing paging functionality to queries

New in Version 1.1.0:

• Ability to read group hierarchies.
• New option useGroupPathAsCamundaGroupId for readable group IDs. Helps when configuring authorizations.

Version 1.0.0:

• ReadOnlyIdentityProvider
• Broad support for user and group queries
• Compatible with Spring Boot OAuth2 SSO

Known limitations:

• A strategy to distinguish SYSTEM and WORKFLOW groups is missing. Currently only the administrator group is mapped to type SYSTEM.
• Some query filters are applied on the client side - the Keycloak REST API does not allow full criteria search in all required cases.
• Sort criteria for queries are implemented on the client side - the Keycloak REST API does not allow result ordering.
• Tenants are currently not supported.

Prerequisites in your Keycloak realm

1. Keycloak docker images can be found on Keycloak Docker Hub.

2. Create a new client named camunda-identity-service with access type confidential and service accounts enabled: Please be aware, that beginning with Keycloak 18, you do not only have to configure a valid redirect URL, but a valid post logout redirect URL as well. To keep things easy values can be the same.

3. In order to use refresh tokens set the "Use Refresh Tokens For Client Credentials Grant" option within the "OpenID Connect Compatibility Modes" section (available in newer Keycloak versions):

   

4. Add the roles query-groups, query-users, view-users to the service account client roles of your realm (choose realm-management or master-realm, depending on whether you are using a separate realm or master):

5. Your client credentials can be found here:

6. Once you're done with the basic setup you're now ready to manage your users and groups with Keycloak. Please keep in mind, that in order to make the Keycloak Identity Provider work, you will need at least one dedicated Camunda admin group or Camunda admin user in your realm. Whether you create this group/user manually or import it using the LDAP user federation or any other Identity Provider is up to you.

Usage with Camunda Spring Boot

Maven Dependencies:

<dependency>
    <groupId>org.camunda.bpm.extension</groupId>
    <artifactId>camunda-platform-7-keycloak</artifactId>
    <version>7.21.0</version>
</dependency>

Add the following class to your Camunda Spring Boot application in order to activate the Keycloak Identity Provider Plugin:

package <your-package>;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.camunda.bpm.extension.keycloak.plugin.KeycloakIdentityProviderPlugin;

@Component
@ConfigurationProperties(prefix="plugin.identity.keycloak")
public class KeycloakIdentityProvider extends KeycloakIdentityProviderPlugin {
}

Configuration in application.yaml will then look as follows:

camunda.bpm:
  ...
  authorization:
    enabled: true

plugin.identity.keycloak:
  keycloakIssuerUrl: https://<your-keycloak-server>/auth/realms/<realm-name>
  keycloakAdminUrl: https://<your-keycloak-server>/auth/admin/realms/<realm-name>
  clientId: camunda-identity-service
  clientSecret: 42aa42bb-1234-4242-a24a-42a2b420cde0
  useEmailAsCamundaUserId: true
  administratorGroupName: camunda-admin

Hint: the engine must not create a user upon startup - the plugin is a ReadOnlyIdentityProvider. Hence you must not configure an admin-user for camunda.bpm in your application.yaml. The following configuration will likely cause errors upon startup:

camunda.bpm:
# DON'T DO THIS
  admin-user:
    id: demo
    password: demo
    firstName: Camunda

The admin-user part must be deleted in order to work properly. The recommended procedure for creating the admin user and admin group in Keycloak is to have the deployment pipeline do this during the environment setup phase.

A list of configuration options can be found below:

Property	Description
keycloakIssuerUrl	The basic issuer URL of your Keycloak server including the realm. Sample for master realm: https://<your-keycloak-server>/auth/realms/master
keycloakAdminUrl	The admin URL of the Keycloak server REST API including the realm. Sample for master realm: https://<your-keycloak-server>/auth/admin/realms/master
clientId	The Client ID of your application.
clientSecret	The Client Secret of your application.
useEmailAsCamundaUserId	Whether to use the Keycloak email attribute as Camunda's user ID. Default is false. This is option is a fallback in case you don't use SSO and want to login using Camunda's web interface with your mail address and not the cryptic internal Keycloak ID. Keep in mind that you will only be able to login without SSO with Keycloak's internally managed users and users managed by the LDAP / Keberos User federation.
useUsernameAsCamundaUserId	Whether to use the Keycloak username attribute as Camunda's user ID. Default is false. In the default case the plugin will use the internal Keycloak ID as Camunda's user ID.
useGroupPathAsCamundaGroupId	Whether to use the Keycloak unique group path as Camunda's group ID. Default is false. In the default case the plugin will use the internal Keycloak ID as Camunda's group ID. This flag is particularly useful in case you want to have human readable group IDs and recommended when using groups in Camunda's authorization management. Since 1.1.0
enforceSubgroupsInGroupQuery	Starting with Keycloak version 23 the group query without any other search parameters does not automatically return subgroups within the result. Set this flag to true in case you use subgroups together with Keycloak 23 or higher. Otherwise leave it to the default false and benefit from better performance. Since 7.21.1
administratorGroupName	The name of the administrator group. If this name is set and engine authorization is enabled, the plugin will create group-level Administrator authorizations on all built-in resources.
administratorUserId	The ID of the administrator user. If this ID is set and engine authorization is enabled, the plugin will create user-level Administrator authorizations on all built-in resources.
authorizationCheckEnabled	If this property is set to true, then authorization checks are performed when querying for users or groups. Otherwise authorization checks are not performed when querying for users or groups. Default: true. Note: If you have a huge amount of Keycloak users or groups we advise to set this property to false to improve the performance of the user and group query.
maxResultSize	Maximum result size of queries against the Keycloak API. Default: 250. Beware: Setting the parameter to a too low value can lead to unexpected effects. Keep in mind that parts of the filtering takes place on the client side / within the plugin itself. Setting the parameter to a too high value can lead to performance and memory issues. Since 1.5.0
maxHttpConnections	Maximum number HTTP connections for the Keycloak connection pool. Default: 50
disableSSLCertificateValidation	Whether to disable SSL certificate validation. Default: false. Useful in test environments.
proxyUri	Optional URI of a proxy to use. Default: null, example: http://proxy:81. Since 2.0.0
proxyUser	Optional username for proxy authentication. Default: null. Since 2.0.0
proxyPassword	Optional password for proxy authentication. Default: null. Since 2.0.0

Caching options

This is a ReadOnlyIdentityProvider which translates all queries against the Camunda IdentityService in REST queries against Keycloak. Under high load it makes sense to not request the same things again and again, especially since the data of users and groups do not change every second. Therefore this plugin provides an optional cache feature.

User and group query caching

In order to activate caching of user and group queries you have the following options available:

Property	Description
cacheEnabled	Enable caching of user and group queries to Keycloak to improve performance. Default: false. Since 2.2.0
maxCacheSize	Maximum size of the cache. Least used entries are evicted when this limit is reached. Default: 500. Since 2.2.0
cacheExpirationTimeoutMin	Time (in minutes) after which a cached entry is evicted. Default: 15 minutes. Since 2.2.0

Besides caching of user and group queries there is another scenario where caching could make sense.

Login caching

Imagine a setup with lots of External Task Clients using HTTP Basic Auth against the Camunda REST API (e.g. set camunda.bpm.run.auth.enabled: true when using Camunda Run). Your External Task Clients then might trigger the IdentityProvider's checkPassword function at high frequency. This function requests a token from Keycloak each time it is called. In case of a successful response the login is treated as valid. High frequency then means requesting lots of tokens - in the worst case all for the same user and before an already delivered token has timed out. Therefore this plugin provides an optional login cache feature as well.

In order to activate the login cache you have the following options available:

Property	Description
loginCacheEnabled	Enable caching of login / check password requests to Keycloak to improve performance. Not applicable in case of SSO scenarios, but useful e.g. in case of External Tasks clients using HTTP Basic Auth only. Default: false Since 2.2.3
loginCacheSize	Maximum size of the login cache. Least used entries are evicted when this limit is reached. Default: 50. Since 2.2.3
loginCacheExpirationTimeoutMin	Time (in minutes) after which a login cache entry is evicted. Default: 15 minutes. Since 2.2.3

On the downside this feature bypasses the password grant exchange function of Keycloak until the configured timeout expires. So the choice is yours. Please be aware that the login cache is not applicable for SSO scenarios.

Activating Single Sign On

In this part, we’ll discuss how to activate SSO – Single Sign On – for the Camunda Web App using Spring Boot and Spring Security 5.2.x OAuth 2.0 Client capabilities in combination with this plugin and Keycloak as authorization server.

In order to setup Spring Boot's OAuth2 security add the following Maven dependencies to your project:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-oauth2-client</artifactId>
</dependency>

What we need is a bridge between Spring Security and Camunda. Hence insert a KeycloakAuthenticationProvider as follows:

/**
  * OAuth2 Authentication Provider for usage with Keycloak and KeycloakIdentityProviderPlugin. 
  */
public class KeycloakAuthenticationProvider extends ContainerBasedAuthenticationProvider {

    @Override
    public AuthenticationResult extractAuthenticatedUser(HttpServletRequest request, ProcessEngine engine) {

        // Extract user-name-attribute of the OAuth2 token
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        if (!(authentication instanceof OAuth2AuthenticationToken) || !(authentication.getPrincipal() instanceof OidcUser)) {
            return AuthenticationResult.unsuccessful();
        }
        String userId = ((OidcUser)authentication.getPrincipal()).getName();
        if (StringUtils.isEmpty(userId)) {
            return AuthenticationResult.unsuccessful();
        }

        // Authentication successful
        AuthenticationResult authenticationResult = new AuthenticationResult(userId, true);
        authenticationResult.setGroups(getUserGroups(userId, engine));

        return authenticationResult;
    }

    private List<String> getUserGroups(String userId, ProcessEngine engine){
        List<String> groupIds = new ArrayList<>();
        // query groups using KeycloakIdentityProvider plugin
        engine.getIdentityService().createGroupQuery().groupMember(userId).list()
            .forEach( g -> groupIds.add(g.getId()));
        return groupIds;
    }

}

Last but not least add a security configuration and enable OAuth2 SSO:

/**
 * Camunda Web application SSO configuration for usage with KeycloakIdentityProviderPlugin.
 */
@ConditionalOnMissingClass("org.springframework.test.context.junit.jupiter.SpringExtension")
@EnableWebSecurity
@Configuration
public class WebAppSecurityConfig {

    @Bean
    @Order(2)
    public SecurityFilterChain httpSecurity(HttpSecurity http) throws Exception {
        return http
                .csrf(csrf -> csrf
                        .ignoringRequestMatchers(antMatcher("/api/**"), antMatcher("/engine-rest/**")))
                .authorizeHttpRequests(authorize -> authorize
                        .requestMatchers(
                                antMatcher("/assets/**"),
                                antMatcher("/app/**"),
                                antMatcher("/api/**"),
                                antMatcher("/lib/**"))
                        .authenticated()
                        .anyRequest()
                        .permitAll())
                .oauth2Login(withDefaults())
                .build();
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Bean
    public FilterRegistrationBean containerBasedAuthenticationFilter(){

        FilterRegistrationBean filterRegistration = new FilterRegistrationBean();
        filterRegistration.setFilter(new ContainerBasedAuthenticationFilter());
        filterRegistration.setInitParameters(Collections.singletonMap("authentication-provider", "org.camunda.bpm.extension.keycloak.showcase.sso.KeycloakAuthenticationProvider"));
        filterRegistration.setOrder(201); // make sure the filter is registered after the Spring Security Filter Chain
        filterRegistration.addUrlPatterns("/app/*");
        return filterRegistration;
    }

    // The ForwardedHeaderFilter is required to correctly assemble the redirect URL for OAUth2 login. 
    // Without the filter, Spring generates an HTTP URL even though the container route is accessed through HTTPS.
    @Bean
    public FilterRegistrationBean<ForwardedHeaderFilter> forwardedHeaderFilter() {
        FilterRegistrationBean<ForwardedHeaderFilter> filterRegistrationBean = new FilterRegistrationBean<>();
        filterRegistrationBean.setFilter(new ForwardedHeaderFilter());
        filterRegistrationBean.setOrder(Ordered.HIGHEST_PRECEDENCE);
        return filterRegistrationBean;
    }

    @Bean
    @Order(0)
    public RequestContextListener requestContextListener() {
        return new RequestContextListener();
    }
}

Finally configure Spring Security with your Keycloak Single Page Web App client-id and client-secret in application.yaml as follows:

# Spring Boot Security OAuth2 SSO
spring.security.oauth2:
  client:
    registration:
      keycloak:
        provider: keycloak
        client-id: camunda-identity-service
        client-secret: yyy2121abc21def2121ghi212132121abc21def2121ghi2121eyyy
        authorization-grant-type: authorization_code
        redirect-uri: "{baseUrl}/{action}/oauth2/code/{registrationId}"
        scope: openid, profile, email
    provider:
      keycloak:
        issuer-uri: https://<your-keycloak-server>/auth/realms/camunda
        authorization-uri: https://<your-keycloak-server>/auth/realms/camunda/protocol/openid-connect/auth
        user-info-uri: https://<your-keycloak-server>/auth/realms/camunda/protocol/openid-connect/userinfo
        token-uri: https://<your-keycloak-server>/auth/realms/camunda/protocol/openid-connect/token
        jwk-set-uri: https://<your-keycloak-server>/auth/realms/camunda/protocol/openid-connect/certs
        # set user-name-attribute one of: 
        # - sub                -> default; using keycloak ID as camunda user ID
        # - email              -> useEmailAsCamundaUserId=true
        # - preferred_username -> useUsernameAsCamundaUserId=true
        user-name-attribute: email

Beware: You have to set the parameter user-name-attribute of the spring.security.oauth2.client.provider.keycloak in a way that it matches the configuration of your KeycloakIdentityProviderPlugin:

• useEmailAsCamundaUserId: true - set user-name-attribute: email
• useUsernameAsCamundaUserId: true - set user-name-attribute: preferred_username
• neither of the above two, using Keycloak's ID as default - set user-name-attribute: sub

Keep in mind that Keycloak's email attribute might not always be unique, depending on your setup. Email uniqueness can be configured on a per realm level depending on the setting Login with email.

Quickstart

As a quickstart into using and configuring the plugin we recommend to have a look at the Installation on Camunda Platform Run. You'll find a chapter "Docker Sample Setup" at the end of the README. This is a simple starting point.

If your intention is a complete SSO setup on Kubernetes you'll be more happy with the next reference.

Sample Spring Boot Project with SSO on Kubernetes

A sample project using this plugin including a basic SSO and Kubernetes setup can be found under Camunda Showcase for Spring Boot & Keycloak Identity Provider. See directory examples.

Installation on Apache Tomcat with Shared Process Engine

Even if from an architectural point of view Spring Boot is currently the most recommended approach for cloud scenarios, it is of course possible to install the plugin in other Camunda distributions as well. A description on how to install the plugin on an Apache Tomcat full distribution can be found under Installation on Tomcat. See directory examples.

Installation on Camunda Platform Run

A description on how to install the plugin on Camunda BPM Run can be found under Installation on Camunda BPM Run. See directory examples.

Installation on JBoss/Wildfly

A description on how to install the plugin on a JBoss/Wildfly can be found under Installation on JBoss/Wildfly. See directory examples.

Unit testing the plugin

In order to run the unit tests I have used a local docker setup of Keycloak with docker-compose.yml as follows:

version: "3.9"

services:
  jboss.keycloak:
    image: quay.io/keycloak/keycloak:24.0.3
    restart: unless-stopped
    environment:
      TZ: Europe/Berlin
      DB_VENDOR: h2
      KEYCLOAK_ADMIN: keycloak
      KEYCLOAK_ADMIN_PASSWORD: keycloak1!
      KC_HTTP_RELATIVE_PATH: /auth
    ports:
      - "8443:8443"
      - "8080:8080"
    command:
      - start-dev

For details see documentation on Running Keycloak in a container.

Maven test setup

Running unit tests from Maven requires configuring the details of a running Keycloak server. This can be achieved by setting the following environment variables:

Environment Variable	Description
KEYCLOAK_URL	Keycloak server URL. Default value: http://localhost:8080/auth
KEYCLOAK_ADMIN_USER	The admin user of the Keycloak server. Default value: keycloak
KEYCLOAK_ADMIN_PASSWORD	The admin password of the Keycloak server. Default value: keycloak1!
KEYCLOAK_ENFORCE_SUBGROUPS_IN_GROUP_QUERY	Wether to enforce subgroup results in group queries when testing with Keycloak >= 23.0.0 Default value: true

In case you choose Keycloak in the new Quarkus distribution, please be aware that /auth has been removed from the default context path. Hence, it is required to change the KEYCLOAK_URL for the tests. Tests run successfully against the Quarkus distribution, in case you start Keycloak in Development mode.

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That's it. Have a happy Keycloak experience and focus on what really matters: the core processes of your customer.

Brought to you by:

Gunnar von der Beck, Accso - Accelerated Solutions GmbH

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Resources

• Issue Tracker
• Contributing

Maintainer

• Gunnar von der Beck

License

License: Apache License 2.0