Tenancy Laravel Package

Technical Evaluation

Architecture Fit

• Multi-tenancy Pattern: The package implements database-per-tenant isolation with minimal code changes, leveraging Laravel’s built-in features (e.g., database connections, middleware). This aligns well with SaaS architectures requiring strict tenant separation.
• Middleware-Based Tenant Resolution: Uses middleware to dynamically switch database contexts based on hostname, subdomains, or custom resolvers, reducing boilerplate.
• Zero-Configuration for Basic Use: No model traits or class overrides required, making it ideal for greenfield projects or migrations where minimal disruption is critical.
• Extensibility: Supports custom tenant resolvers (e.g., path-based, header-based) and integrates with Vite, Queues, Caching, and Storage for full-stack tenancy.

Integration Feasibility

• Laravel Ecosystem Compatibility: Works seamlessly with Laravel 10–13, PHP 8+, and supports MySQL, PostgreSQL, MariaDB, and SQLite. The package’s maturity (4.3K stars, active maintenance) reduces integration risk.
• Database Schema Isolation: Automatically prefixes tables (configurable) or uses separate schemas/databases per tenant, avoiding shared-table anti-patterns.
• Queue/Job Tenancy: Supports tenant-aware job processing with fixes for edge cases (e.g., queue:retry), critical for async workflows.
• Asset Isolation: Vite and filesystem support ensures tenant-specific assets (CSS/JS) are served correctly via subdomain paths.

Technical Risk

• Performance Overhead:
  • Middleware-based tenant resolution adds ~1–5ms latency per request (benchmark in staging).
  • Cache invalidation (e.g., tenant resolvers) may require tuning for high-scale apps.
• Migration Complexity:
  • Existing apps with shared-table tenancy or custom database logic may need refactoring.
  • Zero-downtime migrations: Requires careful sequencing (see Integration Approach).
• Edge Cases:
  • Impersonation: Tenant switching via middleware must handle edge cases (e.g., admin users accessing multiple tenants).
  • Queue Workers: Workers must revert to the central context post-job execution (fixed in v3.8.5 but requires testing).
• Vendor Lock-in:
  • Custom tenant resolvers or middleware may become tightly coupled to the package.

Key Questions

1. Tenant Identification Strategy:
   • Will hostname/subdomain-based resolution suffice, or are custom resolvers (e.g., API headers) needed?
   • How will tenant onboarding/offboarding (e.g., DNS changes) be automated?
2. Database Strategy:
   • Separate databases (recommended for isolation) vs. schemas/tables (simpler but less isolated).
   • How will backups/restores be handled per tenant?
3. Performance:
   • What’s the expected tenant count? Will cache warming (e.g., resolver cache) be needed?
   • Are read replicas required for scaling?
4. Existing Codebase:
   • Does the app use shared-table tenancy or custom database logic that conflicts with stancl/tenancy?
   • Are there legacy migrations that need rewriting?
5. DevOps:
   • How will tenant-specific configurations (e.g., .env overrides) be managed?
   • Will Docker/Kubernetes require custom networking for subdomains?

Integration Approach

Stack Fit

• Laravel Core: Fully compatible with Laravel 10–13 (tested up to v3.10.0). Drop-in replacement for manual tenancy logic.
• Database: Supports MySQL, PostgreSQL, MariaDB, SQLite with schema/database isolation. No ORM changes required.
• Caching: Tenant-aware cache tags (e.g., Cache::tags()) work out-of-the-box.
• Queues: Tenant context preserved across jobs (fixed in v3.5.0+). Requires QueueTenancyBootstrapper.
• Assets: Vite and filesystem support for tenant-specific assets (e.g., tenant1.app/assets/).
• Testing: Built-in support for tenant switching in tests (e.g., Tenancy::impersonate()).

Migration Path

Compatibility

• Breaking Changes:
  • Laravel 9 support dropped in v3.9.0 (app must upgrade to L10+).
  • PHP < 8.0 unsupported (v3.5.3+).
• Dependencies:
  • Requires Laravel’s database connection switching (no conflicts with custom implementations).
  • Vite: Uses tenancy:assetPathResolver for tenant-specific asset paths.
• Customizations:
  • Override default behavior via service providers (e.g., custom tenant resolvers).
  • Extend Tenant model for tenant-specific logic.

Sequencing

1. Staging Validation:
   • Test with a subset of tenants (e.g., 5–10) to validate performance and data isolation.
   • Simulate failures (e.g., database connection drops) to test recovery.
2. Phased Rollout:
   • Phase 1: New tenants use stancl/tenancy; existing tenants remain on legacy system.
   • Phase 2: Migrate legacy tenants in batches (e.g., by region).
   • Phase 3: Deprecate legacy tenancy logic.
3. Rollback Plan:
   • Maintain dual-writable setup during migration (e.g., sync data between old/new systems).
   • Use Tenancy::disable() for emergency fallbacks.

Operational Impact

Maintenance

• Package Updates:
  • Monitor stancl/tenancy for Laravel version support (e.g., v3.10.0 added L13 support).
  • Critical fixes: Backport patches for issues like queue worker context leaks (v3.8.5).
• Tenant Management:
  • Automate tenant onboarding/offboarding via CLI or admin panel (e.g., php artisan tenancy:create).
  • Monitor database growth (separate databases may require separate backups).
• Logging/Monitoring:
  • Track tenant resolution failures (e.g., missing resolvers, DB errors).
  • Monitor queue job tenancy (e.g., jobs stuck in wrong tenant context).

Support

• Common Issues:
  • Tenant not found: Validate hostname/subdomain resolvers (e.g., PathTenantResolver).
  • Queue jobs failing: Ensure QueueTenancyBootstrapper is registered (fixed in v3.5.0+).
  • Asset loading: Verify Vite resolver paths (e.g., tenant1.app/assets/).
• Debugging Tools:
  • Tenancy::tenant() to inspect current tenant.
  • Tenancy::impersonate() for admin access.
  • php artisan tenancy:list to audit tenants.
• Documentation Gaps:
  • Clarify impersonation limits (e.g., admin users with multi-tenant access).
  • Document backup strategies for isolated databases.

Scaling

• Horizontal Scaling:
  • Stateless workers: Queue workers can scale horizontally (tenant context is job-scoped).
  • Database load: Separate databases reduce contention but increase backup complexity.
• Performance Bottlenecks:
  • Tenant resolution: Cache resolver results (e.g., Cache::remember).
  • Database connections: Use connection pooling (e.g., pgsql:pool for PostgreSQL).
  • Asset delivery: CDN tenant-specific assets to reduce origin load.
• Multi-Region:
  • Deploy tenant databases regionally (e.g., tenant1.us.db, tenant1.eu.db).
  • Use global tenant resolvers (e.g., geolocation-based).

Failure Modes

| Scenario | Impact | Mitigation