🏢 EPIC: Complete Multi-Tenancy System Implementation

🚀 Summary

This massive PR transforms MCP Gateway from a single-tenant system into a production-ready enterprise multi-tenant platform with team-based resource scoping, comprehensive authentication, and enterprise SSO integration.

Impact: Complete architectural transformation enabling secure team collaboration, enterprise SSO integration, and scalable multi-tenant deployments.

🎯 Issues Closed

Primary Epic:

• Closes [EPIC]: Complete Enterprise Multi-Tenancy System with Team-Based Resource Scoping #860 - [EPIC]: Complete Enterprise Multi-Tenancy System with Team-Based Resource Scoping

Core Security & Authentication:

• Closes [SECURITY FEATURE]: Database-Backed User Authentication with Argon2id (replace BASIC auth) #544 - Database-Backed User Authentication with Argon2id (replace BASIC auth)
• Closes [SECURITY FEATURE]: Role-Based Access Control (RBAC) - User/Team/Global Scopes for full multi-tenancy support #283 - Role-Based Access Control (RBAC) - User/Team/Global Scopes for full multi-tenancy support
• Closes [SECURITY FEATURE]: Configurable Password and Secret Policy Engine #426 - Configurable Password and Secret Policy Engine
• Closes [Feature Request]: Epic: Secure JWT Token Catalog with Per-User Expiry and Revocation #87 - Epic: Secure JWT Token Catalog with Per-User Expiry and Revocation
• Closes [SECURITY FEATURE]: Per-Virtual-Server API Keys with Scoped Access #282 - Per-Virtual-Server API Keys with Scoped Access

SSO Integration:

• Closes [AUTH FEATURE]: Authentication & Authorization - SSO + Identity-Provider Integration #220 - Authentication & Authorization - SSO + Identity-Provider Integration
• Closes [Feature Request]: Authentication & Authorization - Google SSO Integration Tutorial (Depends on #220) #278 - Authentication & Authorization - Google SSO Integration Tutorial
• Closes [Feature Request]: Authentication & Authorization - IBM Security Verify Enterprise SSO Integration (Depends on #220) #859 - Authentication & Authorization - IBM Security Verify Enterprise SSO Integration

Future Work:

• Provides foundation for [Feature Request]: ABAC Virtual Server Support #706 - ABAC Virtual Server Support (RBAC foundation implemented, ABAC policies not yet implemented)

🔥 Major Features Implemented

🔐 Authentication & Authorization System

• ✅ Email-based Authentication with Argon2id password hashing
• ✅ Complete RBAC System with Platform Admin, Team Owner, Team Member roles
• ✅ Enhanced JWT Tokens with team context and scoped permissions
• ✅ Password Policy Engine with configurable security requirements
• ✅ Multi-Provider SSO Framework (GitHub, Google, IBM Security Verify)

👥 Team Management System

• ✅ Personal Teams Auto-Creation - Every user gets a personal team
• ✅ Multi-Team Membership - Users can belong to multiple teams with roles
• ✅ Team Invitation System - Email-based invitations with secure tokens
• ✅ Team Visibility Controls - Private/Public team discovery
• ✅ Team Administration - Complete team lifecycle management

🔒 Resource Scoping & Visibility

• ✅ Three-Tier Resource Visibility System:
  • Private: Owner-only access
  • Team: Team member access
  • Public: Cross-team access
• ✅ Applied to All Resource Types: Tools, Servers, Resources, Prompts, A2A Agents
• ✅ Team-Scoped API Endpoints with proper access validation
• ✅ Cross-Team Resource Discovery for public resources

🏗️ Platform Administration

• ✅ Platform Admin Role separate from team roles
• ✅ Domain-Based Auto-Assignment via SSO (SSO_AUTO_ADMIN_DOMAINS)
• ✅ Enterprise Domain Trust (SSO_TRUSTED_DOMAINS)
• ✅ System-Wide Team Management for administrators

🗄️ Database & Infrastructure

• ✅ Complete Multi-Tenant Database Schema with proper indexing
• ✅ Team-Based Query Filtering for performance optimization
• ✅ Automated Migration Strategy from single-tenant to multi-tenant
• ✅ All APIs Redesigned to be team-aware

📐 System Architecture

This implementation introduces a comprehensive multi-tenant architecture:

graph TB
    subgraph "Authentication Layer"
        Email[Email Authentication<br/>Argon2id Hashing]
        SSO[Multi-Provider SSO<br/>GitHub, Google, IBM Verify]
        JWT[Enhanced JWT Tokens<br/>Team Context + Scoped Access]
    end

    subgraph "Team Management"
        PersonalTeams[Personal Teams<br/>Auto-Creation]
        MultiTeam[Multi-Team Membership<br/>Owner/Member Roles]
        Invitations[Email Invitations<br/>Token-Based Workflow]
    end

    subgraph "Resource Scoping"
        ResourceVis[Three-Tier Visibility<br/>Private/Team/Public]
        TeamAPI[Team-Scoped APIs<br/>All Resource Types]
        CrossTeam[Cross-Team Access<br/>Public Resources]
    end

    subgraph "Platform Administration"
        PlatformAdmin[Platform Admin Role<br/>System-Wide Access]
        DomainMap[Domain-Based Assignment<br/>Auto-Admin via SSO]
    end

    Email --> JWT
    SSO --> JWT
    JWT --> MultiTeam
    PersonalTeams --> MultiTeam
    MultiTeam --> ResourceVis
    ResourceVis --> TeamAPI
    PlatformAdmin --> DomainMap

🗄️ Database Schema Changes

New Multi-Tenant Tables:

-- User management
CREATE TABLE email_users (
    email VARCHAR(255) PRIMARY KEY,
    password_hash VARCHAR(255) NOT NULL,
    full_name VARCHAR(255),
    is_admin BOOLEAN DEFAULT FALSE,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);

-- Team management
CREATE TABLE email_teams (
    id UUID PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    description TEXT,
    visibility VARCHAR(20) DEFAULT 'private',
    owner_email VARCHAR(255) REFERENCES email_users(email),
    is_personal BOOLEAN DEFAULT FALSE,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);

-- Team membership
CREATE TABLE email_team_members (
    id UUID PRIMARY KEY,
    team_id UUID REFERENCES email_teams(id),
    user_email VARCHAR(255) REFERENCES email_users(email),
    role VARCHAR(50) DEFAULT 'member',
    joined_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    UNIQUE(team_id, user_email)
);

-- Team invitations
CREATE TABLE email_team_invitations (
    id UUID PRIMARY KEY,
    team_id UUID REFERENCES email_teams(id),
    invited_email VARCHAR(255),
    invited_by_email VARCHAR(255) REFERENCES email_users(email),
    token VARCHAR(255) UNIQUE NOT NULL,
    role VARCHAR(50) DEFAULT 'member',
    expires_at TIMESTAMP WITH TIME ZONE,
    status VARCHAR(20) DEFAULT 'pending',
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);

Extended Resource Tables:

All existing resource tables (tool, server, resource, prompt, a2a_agent) extended with:

ALTER TABLE [resource_table] ADD COLUMN team_id UUID REFERENCES email_teams(id);
ALTER TABLE [resource_table] ADD COLUMN owner_email VARCHAR(255) REFERENCES email_users(email);
ALTER TABLE [resource_table] ADD COLUMN visibility VARCHAR(20) DEFAULT 'private';

🔧 Configuration Changes

New Environment Variables:

Core Multi-Tenancy:

# Team Management
AUTO_CREATE_PERSONAL_TEAMS=true
PERSONAL_TEAM_PREFIX=personal
MAX_TEAMS_PER_USER=50
MAX_MEMBERS_PER_TEAM=100

# Invitations
INVITATION_EXPIRY_DAYS=7
REQUIRE_EMAIL_VERIFICATION_FOR_INVITES=true

# Platform Administration
[email protected]
PLATFORM_ADMIN_PASSWORD=changeme
PLATFORM_ADMIN_FULL_NAME="Platform Administrator"

Authentication:

# Email Authentication
EMAIL_AUTH_ENABLED=true
ARGON2ID_TIME_COST=3
ARGON2ID_MEMORY_COST=65536
ARGON2ID_PARALLELISM=1

# Password Policies
PASSWORD_MIN_LENGTH=8
PASSWORD_REQUIRE_UPPERCASE=false
PASSWORD_REQUIRE_NUMBERS=false
PASSWORD_REQUIRE_SPECIAL=false

SSO Integration:

# Multi-Provider SSO
SSO_ENABLED=true
SSO_TRUSTED_DOMAINS=["company.com","trusted-partner.com"]
SSO_AUTO_ADMIN_DOMAINS=["company.com"]
SSO_AUTO_CREATE_USERS=true
SSO_PRESERVE_ADMIN_AUTH=true

# GitHub SSO
SSO_GITHUB_ENABLED=true
SSO_GITHUB_CLIENT_ID=your-github-client-id
SSO_GITHUB_CLIENT_SECRET=your-github-client-secret

# Google SSO  
SSO_GOOGLE_ENABLED=true
SSO_GOOGLE_CLIENT_ID=your-google-client-id
SSO_GOOGLE_CLIENT_SECRET=your-google-client-secret

# IBM Security Verify SSO
SSO_IBM_VERIFY_ENABLED=true
SSO_IBM_VERIFY_CLIENT_ID=your-ibm-client-id
SSO_IBM_VERIFY_CLIENT_SECRET=your-ibm-client-secret
SSO_IBM_VERIFY_ISSUER=https://tenant.verify.ibm.com/oidc/endpoint/default

🔐 Security Enhancements

Multi-Tenant Security Model:

• ✅ Data Isolation: Team-scoped queries prevent cross-tenant data access
• ✅ Resource Ownership: Every resource has owner_email and team_id validation
• ✅ Visibility Enforcement: Private/Team/Public visibility strictly enforced
• ✅ Access Logging: Authentication and authorization events tracked
• ✅ Secure Tokens: Invitation tokens with expiration and single-use validation

Enterprise Security Controls:

• ✅ Domain Restrictions: Corporate domain enforcement via SSO_TRUSTED_DOMAINS
• ✅ MFA Support: Automatic enforcement of SSO provider MFA policies
• ✅ Conditional Access: Location/device-based access controls via SSO providers
• ✅ Password Security: Argon2id hashing with configurable parameters
• ✅ JWT Enhancements: Team context and scoped permissions in tokens

🚀 API Changes

New Authentication Endpoints:

• POST /auth/email/register - Email user registration
• POST /auth/email/login - Email user login
• GET /auth/sso/providers - List available SSO providers
• GET /auth/sso/login/{provider} - Initiate SSO login
• POST /auth/sso/callback/{provider} - Handle SSO callback

New Team Management Endpoints:

• GET /teams - List user's teams
• POST /teams - Create new team
• GET /teams/{team_id} - Get team details
• PUT /teams/{team_id} - Update team
• DELETE /teams/{team_id} - Delete team (non-personal only)
• POST /teams/{team_id}/invitations - Invite user to team
• GET /teams/{team_id}/members - List team members
• DELETE /teams/{team_id}/members/{user_email} - Remove team member

Enhanced Resource Endpoints:

All resource endpoints (tools, servers, resources, prompts, a2a agents) now support:

• ?team_id=uuid - Filter by team
• ?visibility=private|team|public - Filter by visibility
• team_id, owner_email, visibility fields in request/response bodies

📚 Documentation Added

Complete Documentation Suite:

• ✅ Architecture Documentation: docs/docs/architecture/multitenancy.md (934 lines)
• ✅ SSO Integration Tutorials:
  • docs/docs/manage/sso-ibm-tutorial.md - IBM Security Verify setup
  • docs/docs/manage/sso-github-tutorial.md - GitHub SSO setup
  • docs/docs/manage/sso-google-tutorial.md - Google SSO setup
• ✅ Configuration Reference: Complete environment variable documentation
• ✅ Migration Guide: Single-tenant to multi-tenant upgrade path
• ✅ API Reference: Team-scoped endpoint documentation

Enterprise Deployment Guides:

• ✅ Production Checklist: Security requirements and best practices
• ✅ Troubleshooting Guide: Common multi-tenant scenarios and solutions
• ✅ Performance Tuning: Team-based indexing and query optimization

🧪 Testing

Test Coverage:

• ✅ Unit Tests: All new authentication and team management code
• ✅ Integration Tests: Team-scoped API endpoint validation
• ✅ Security Tests: RBAC permission enforcement
• ✅ Migration Tests: Database schema migration validation
• ✅ SSO Tests: Multi-provider authentication flows

Test Categories:

• Authentication system tests (email + SSO)
• Team management workflow tests
• Resource visibility and access control tests
• Database migration and rollback tests
• API endpoint authorization tests
• JWT token validation tests

⚡ Performance Optimizations

Database Optimizations:

• ✅ Team-Based Indexing: Optimized queries for team-scoped resources
• ✅ Query Performance: Efficient team membership lookups
• ✅ Connection Pooling: Optimized for multi-tenant workloads
• ✅ Index Strategy: Strategic indexing on team_id, owner_email, visibility

API Performance:

• ✅ Team Context Caching: JWT team memberships cached for performance
• ✅ Resource Filtering: Efficient team-scoped resource queries
• ✅ Bulk Operations: Optimized multi-resource operations

🔄 Migration Strategy

Backward Compatibility:

• ✅ Feature Flags: Multi-tenancy can be enabled/disabled via configuration
• ✅ API Compatibility: Existing API endpoints remain functional
• ✅ Data Migration: Automated migration of existing data to multi-tenant schema
• ✅ Rollback Support: Database migrations can be rolled back if needed

Upgrade Path:

1. Database Migration: Automated Alembic migrations add multi-tenant schema
2. Configuration Update: Add multi-tenancy environment variables
3. Feature Enablement: Enable multi-tenancy features via configuration
4. User Migration: Existing users automatically get personal teams
5. SSO Integration: Configure SSO providers as needed

🏆 Business Impact

Enterprise Readiness:

• ✅ Secure Multi-Tenancy: Enterprise customers can deploy with confidence
• ✅ SSO Integration: Seamless integration with existing identity infrastructure
• ✅ Team Collaboration: Enable collaborative workflows within organizations
• ✅ Resource Governance: Proper resource scoping and access controls
• ✅ Compliance Ready: Audit logging and security controls for enterprise requirements

Scalability Improvements:

• ✅ Performance Optimization: Team-based indexing and query filtering
• ✅ Resource Isolation: Proper data separation for compliance requirements
• ✅ Admin Efficiency: Platform-level management for enterprise deployments
• ✅ Multi-Tenant Architecture: Foundation for supporting thousands of teams/users

🎯 Breaking Changes

Database Schema:

• New tables: email_users, email_teams, email_team_members, email_team_invitations
• Extended tables: All resource tables with team_id, owner_email, visibility columns

API Changes:

• New authentication endpoints for email and SSO
• New team management endpoints
• Enhanced resource endpoints with team-scoping parameters

Configuration:

• New required environment variables for multi-tenancy features
• SSO provider configuration variables

Note: All changes are backward compatible when multi-tenancy features are disabled.

🚦 Deployment Checklist

Pre-Deployment:

• Database backup completed
• Environment variables configured
• SSO provider applications configured (if using SSO)
• Admin user credentials prepared

Deployment:

• Run database migrations: make alembic-upgrade
• Update environment configuration
• Restart gateway services
• Verify multi-tenancy features enabled
• Test authentication flows

Post-Deployment:

• Create platform admin user
• Test team creation and management
• Verify resource scoping works correctly
• Test SSO integration (if enabled)
• Monitor performance and logs

🎉 Summary

This PR represents a complete architectural transformation of MCP Gateway into a production-ready enterprise multi-tenant platform. The implementation includes:

• 9 major GitHub issues closed (plus foundation for 1 future issue)
• Complete authentication system with email + multi-provider SSO
• Comprehensive team management with roles and permissions
• Three-tier resource scoping for all resource types
• Enterprise security controls with domain restrictions and MFA support
• Production-grade documentation with deployment guides
• Performance-optimized database schema with proper indexing
• Backward-compatible migration path for existing deployments

Result: MCP Gateway now supports multi-tenancy, team collaboration, and SSO integration.