## Configuring a Custom Identity Provider for Camunda BPM

### Key Implementation Steps

**1. Create Custom Identity Provider**
To implement a custom identity provider, you'll need to:
- Implement either `ReadOnlyIdentityProvider` or `WritableIdentityProvider`
- Create a custom SessionFactory
- Develop a ProcessEnginePlugin

### Implementation Structure

public class MyCustomIdentityProviderFactory implements SessionFactory {
    public Class<?> getSessionType() {
        return ReadOnlyIdentityProvider.class;
    }

    public Session openSession() {
        return new MyCustomIdentityProviderSession();
    }
}

public class MyCustomProcessEnginePlugin implements ProcessEnginePlugin {
    @Override
    public void preInit(ProcessEngineConfigurationImpl processEngineConfiguration) {
        CustomIdentityProviderFactory customFactory = new CustomIdentityProviderFactory();
        processEngineConfiguration.setIdentityProviderSessionFactory(customFactory);
    }
}

### Configuration Methods

**1. XML Configuration**
In the `bpm-platform.xml` file, add the custom plugin:

<process-engine name="default">
    <plugins>
        <plugin>
            <class>your.package.MyCustomProcessEnginePlugin</class>
        </plugin>
    </plugins>
</process-engine>

**2. Spring Boot Configuration**
For Spring Boot applications, use the `@Component` annotation and configuration properties:

@Component
@ConfigurationProperties(prefix="plugin.identity.custom")
public class CustomIdentityProvider extends ProcessEnginePlugin {
    // Custom implementation details
}

### Key Considerations

**Authentication and Authorization**
- The custom identity provider handles user authentication
- Camunda's authorization system still manages permissions
- Users and groups are not stored in Camunda's database

**Supported Provider Types**
- **Read-Only**: Retrieve user and group information
- **Writable**: Create, update, and delete users and groups

### Recommended Approaches

1. Start with a simple implementation using hardcoded or stubbed methods
2. Gradually add complexity to match your specific identity management requirements
3. Ensure secure integration with your existing identity system

**Important Notes**:
- Custom providers can connect to various sources (LDAP, REST APIs, databases)
- Multi-tenancy may require additional custom logic
- Always prioritize security in your implementation

### Potential Integration Strategies

- LDAP Integration
- OAuth2/OpenID Connect
- Custom REST-based authentication
- Database-backed identity providers

Citations:
[1] https://docs.camunda.org/manual/7.22/user-guide/spring-boot-integration/spring-security/
[2] https://docs.cibseven.de/manual/1.0/installation/full/tomcat/configuration/
[3] https://forum.camunda.io/t/custom-identity-provider-for-tasklist/26219
[4] https://github.com/camunda/camunda-docs-manual/blob/master/content/user-guide/process-engine/identity-service.md
[5] https://docs.camunda.io/docs/components/best-practices/operations/securing-camunda-c7/
[6] https://docs.camunda.org/manual/7.22/user-guide/process-engine/multi-tenancy/
[7] https://camunda.com/blog/2021/11/qa-the-one-with-the-sso-implementation-in-camunda/
[8] https://docs.camunda.io/docs/self-managed/identity/user-guide/configuration/configure-external-identity-provider/
[9] https://groups.google.com/g/camunda-bpm-users/c/u4777peJYwM
[10] https://dzone.com/articles/springboot-embedded-camunda-single-sign-on-with-saml-idp-provider
[11] https://github.com/camunda-community-hub/camunda-platform-7-keycloak
[12] https://camunda.com/blog/2024/01/camunda-8-4-simplifying-installation-enhancing-user-experience/
[13] https://www.chakray.com/configure-single-sign-on-camunda-keycloak/
[14] https://groups.google.com/g/camunda-bpm-users/c/u4777peJYwM
[15] https://camunda.com/blog/2019/08/keycloak-identity-provider-extension/
[16] https://docs.camunda.io/docs/self-managed/identity/user-guide/configuration/configure-external-identity-provider/
[17] https://forum.camunda.io/t/custom-identity-provider-for-tasklist/26219
[18] https://forum.camunda.io/t/keycloak-camunda-identity-provider-plugin/31063
[19] https://github.com/camunda/camunda-docs-manual/blob/master/content/user-guide/process-engine/identity-service.md