How to design best Auth methods for Multi Tenant Application?

DevOpsGuy

I have multiple microservices for my application and each application is developed in diff programming language. Each microservices has their own frontend and backend. I would like to implement one Common USER authetication from website user and using common authentication methods, each user can navigate. But the issues is, this application is Multi tenant and multi org. that means for each Instance of Application have their own roles based access from admin - mgr - user.
What you suggest?
How should we design this

DevOpsGuy

Let me share more details of.
I have build Wizbrand.com as a Digital Assets Management tools using Wizbrand, Any organization can create ORG. The person who create a org is the ORG admin and Admin can onboard other users such as other admin, manager, user etc with diff level of access. Same time, at wizbrand level, we have site admin concetp. Thus, I believe this is a multi tenant application

Now the issues is. I have added some of the open source solutions as a DAM feature and those application was single tenant and each application can have their OWn admin and different level of users based on the roles and group.

NOW, I am finding an issues integrating Wizbrand Site with Wizbrand's Org Level with these Open Source application which is single tenant.

one more issues is, when wizbrand's org admin add new users at Wizbrand org, how these users would be sync/automatically added in each integrated applications? as each application have their own independent RABC level.

RajeshKumar1

Below is a proposed design and strategy that addresses your multi-tenant, multi-org environment at Wizbrand while integrating single-tenant open source applications with their own independent RBAC.

1. Centralized Identity Provider & Single Sign-On (SSO)

Objective:
Have one “source of truth” for all users at the Wizbrand level so that when an organization is onboarded and new users are created, they are authenticated centrally. This central system will then federate identities to all integrated applications.

How to Achieve It:

Implement a Central IDP:
Deploy a centralized Identity Provider (IDP) (e.g., Keycloak, Auth0, Okta, or even an open-source SAML/OIDC solution) that handles authentication and issues tokens (usually JWTs or SAML assertions).
Use Standard Protocols:
Leverage industry-standard protocols such as SAML 2.0 or OpenID Connect (OIDC). These are language-agnostic and widely supported, which means that even if your integrated applications are single tenant, they can be modified (or wrapped) to accept federated logins.

Benefits:

Unified Login: Users log in once at Wizbrand, and that session is trusted across all services.
Central User Store: All users, roles, and tenant/organization data are managed centrally.
Federation: Integrated applications don’t have to maintain independent user directories if they trust the central IDP.

2. Bridging Multi-Tenant to Single-Tenant Applications

Challenge:
Your integrated open source applications are designed as single-tenant systems with their own independent RBAC. This means they expect a local user store and authentication mechanism. Yet, you want them to automatically recognize users added at the Wizbrand org level.

Proposed Solutions:

A. Federated Authentication with Adaptors

SSO Adapters/Connectors:
Modify (or wrap) each integrated application to support federated authentication. This means:
- When a user attempts to access an integrated app, the app redirects (or validates) the authentication token issued by the central IDP.
- The integrated app maps the identity from the token to its local context.
Local Account Mapping:
Even if the integrated application remains single tenant, a middleware layer (or an adapter) can:
- Check if the user exists in the local store.
- If not, automatically create a local account using data from the central IDP token (e.g., email, name, tenant/organization ID, and roles).
- Map Wizbrand roles to the integrated application’s RBAC roles through a pre-defined configuration or mapping table.

B. User Provisioning via SCIM or Custom Sync Mechanism

SCIM (System for Cross-domain Identity Management):
If the integrated applications support SCIM or can be extended to support it, use SCIM to automatically provision, update, and de-provision user accounts.
Custom Sync API:
Alternatively, implement a background service or webhook mechanism that triggers whenever a user is added/updated in Wizbrand:
- This service calls the integrated applications’ APIs to create or update user records.
- The mapping should consider both the tenant context (so that the application “knows” which org the user belongs to) and the roles (admin, manager, user).

Key Considerations:

Role Mapping:
Since each integrated app may have its own set of roles, establish a role mapping matrix that converts Wizbrand’s roles into roles recognized by the integrated app. For instance, a Wizbrand “org admin” might map to an “administrator” in the open source application.
Tenant Isolation:
Ensure that each integrated application is aware of the tenant context. If the open source app is truly single tenant, you may have to “simulate” multi-tenancy by adding a tenant ID field and filtering data based on that.

3. Workflow Example

User Onboarding at Wizbrand Org Level:
- The org admin adds a new user in Wizbrand.
- The central IDP creates a new user record that includes organization (tenant) and role information.
User Provisioning/Synchronization:
- Option A: A sync service (using SCIM or a custom API) propagates the new user information to each integrated application, creating a corresponding user account and mapping the appropriate roles.
- Option B: When the new user logs into an integrated application for the first time via SSO, the application (through its SSO adapter) automatically checks for a corresponding local account. If none exists, it creates one using the token claims.
User Navigation & SSO:
- The user logs into Wizbrand once.
- The central IDP issues an SSO token (JWT or SAML) that includes the organization and role claims.
- When the user navigates to an integrated application:
  - The application validates the token.
  - The SSO adapter in the integrated application checks local RBAC mappings.
  - The user is granted access as per their mapped role.
Role Management & Updates:
- Changes in user roles (by the org admin) are updated centrally.
- The sync mechanism pushes these updates to the integrated applications, ensuring that permissions remain in sync.

4. Implementation Strategy & Tools

Central Identity Management:

IDP Solutions:
- Keycloak: Open source, supports multi-tenancy and OIDC/SAML.
- Auth0 / Okta: Cloud-based, enterprise-ready solutions.
Protocols:
- OIDC / SAML 2.0: For federated authentication and SSO.

User Provisioning & Sync:

SCIM:
- Use SCIM if the integrated apps support it, or implement a SCIM-compatible endpoint.
Custom API/Webhook:
- Develop a middleware service that listens to user creation/updates at Wizbrand and calls the integrated application’s API to sync users.

SSO Integration for Integrated Apps:

Adapters/Middleware:
- Develop lightweight adapters for each integrated application that can validate the SSO token, map the token’s claims to the local RBAC, and auto-provision local user accounts.
- If the integrated applications are built using popular frameworks, use available libraries to handle OIDC/SAML. For example:
- Node.js: Passport.js with OIDC strategy.
- Python: python-social-auth or flask-oidc.
- Java: Spring Security with OIDC support.
- PHP: SimpleSAMLphp or similar libraries.

Role Mapping:

Maintain a configuration (possibly in a database or configuration file) that defines how Wizbrand roles translate to each integrated application’s roles.
Include tenant-specific rules if different organizations require different mappings.

5. Summary Recommendations

Centralize Authentication:
Use a centralized IDP to handle authentication across your multi-tenant Wizbrand platform.
Leverage Federated SSO:
Integrate SSO via OIDC/SAML for both Wizbrand and each integrated open source application.
Implement User Provisioning:
Use SCIM or a custom synchronization mechanism to automatically create/update user accounts in integrated applications as new users are onboarded at Wizbrand.
Role Mapping & Tenant Awareness:
Ensure that every token includes tenant and role claims and that integrated applications map these claims to their own RBAC settings.
Develop Adapters:
For applications that cannot be easily modified to support federated authentication, create middleware adapters that perform token validation and user provisioning on the fly.

By adopting this design, you can ensure that a user added at the Wizbrand org level is seamlessly and securely propagated to all integrated applications, while still respecting the independent RBAC systems of each application. This unified approach will greatly simplify user management and improve the overall user experience across your digital assets management ecosystem.

Feel free to ask for further details or clarifications on any part of this design!

RajeshKumar1

Thank you for providing more context about your Wizbrand.com Digital Asset Management (DAM) platform. I understand now that you're facing challenges integrating multi-tenant Wizbrand with single-tenant open-source DAM solutions. Let's address your issues and propose some solutions.

Current Architecture

Wizbrand.com: Multi-tenant DAM platform
- Site admin level
- Org level (each org has its own admin, managers, users)
Integrated open-source DAM solutions: Single-tenant
- Each has its own admin and user roles

Main Challenges

Integrating multi-tenant Wizbrand with single-tenant open-source DAM solutions
Syncing user management across Wizbrand and integrated applications

Proposed Solutions

1. Integration Layer

Develop a custom integration layer that acts as a bridge between Wizbrand and the single-tenant applications. This layer would:

Map Wizbrand's multi-tenant structure to individual instances of the single-tenant applications
Handle authentication and authorization across systems
Manage data synchronization between Wizbrand and integrated applications

2. User Synchronization

Implement a centralized identity management system:

Use Wizbrand as the source of truth for user management
Create an automated user provisioning system that:
- Detects new user creation in Wizbrand
- Maps Wizbrand roles to corresponding roles in integrated applications
- Automatically creates accounts in integrated applications
- Syncs user status changes (e.g., deactivation, role changes) across all systems

3. API-driven Integration

Develop or extend APIs for both Wizbrand and the integrated applications:

Create standardized API endpoints for user management, asset handling, and other key functions
Use these APIs to facilitate communication between Wizbrand and integrated applications
Implement webhooks to trigger actions across systems when changes occur

4. Containerization

Consider containerizing the single-tenant applications:

Deploy separate instances for each Wizbrand organization
Use container orchestration (e.g., Kubernetes) to manage these instances
This approach can help maintain isolation between orgs while allowing for centralized management

5. Custom Adapters

Develop custom adapters for each integrated application:

These adapters would handle the translation of Wizbrand's multi-tenant structure to the single-tenant application's structure
Manage authentication, authorization, and data mapping specific to each integrated application

6. Federated Identity Management

Implement a federated identity management solution:

Use standards like SAML or OAuth for single sign-on across all applications
This allows Wizbrand to remain the central authority for user authentication while enabling seamless access to integrated applications

By implementing these solutions, you can create a cohesive ecosystem where Wizbrand acts as the central hub, managing users and organizations, while the integrated single-tenant applications function as specialized tools within this ecosystem. This approach maintains the multi-tenant nature of Wizbrand while leveraging the capabilities of your chosen open-source DAM solutions.