Laravel Singledb Tenancy Laravel Package

Technical Evaluation

Architecture Fit

• Single-DB Multi-Tenancy: Aligns well with SaaS architectures requiring shared infrastructure but isolated data. Avoids the complexity of multi-DB setups while mitigating performance risks (e.g., row-level security, schema-per-tenant alternatives).
• Laravel Native: Leverages Laravel’s Eloquent, middleware, and service container, reducing friction for existing Laravel applications.
• Domain-Based Routing: Supports subdomain/tenant mapping (e.g., tenant1.app.com), a common SaaS pattern, but lacks explicit support for path-based routing (e.g., /tenant1).
• Limitation: No built-in support for schema-per-tenant or row-level security (e.g., PostgreSQL RLS), which may be required for stricter compliance or performance isolation.

Integration Feasibility

• Low-Coupling Design: Middleware-based tenant resolution (TenantMiddleware) and Eloquent global scopes minimize invasive changes.
• Dependency Risk: Relies on Laravel’s core features (e.g., Route::domain(), Model::boot()). Potential conflicts if custom tenant logic exists in the base application.
• Testing Overhead: Tenant-scoped queries require adjustments to existing tests (e.g., mocking current_tenant() or using Tenancy::impersonate()).

Technical Risk

• Performance: Single-table inheritance (STI) or soft-deletes across tenants may impact query performance if not optimized (e.g., proper indexing on tenant_id).
• Migration Complexity: Backfilling tenant_id on existing tables or handling legacy data requires careful planning.
• Edge Cases:
  • Tenant Resolution Failures: No explicit fallback for invalid domains/subdomains (could expose sensitive data).
  • Concurrent Writes: Race conditions possible if tenant resolution isn’t atomic (e.g., during middleware execution).
• Documentation Gaps: Minimal adoption (0 stars/dependents) suggests untested edge cases in production.

Key Questions

1. Tenant Identification: How will tenants be identified (domain/subdomain/path)? Does the package support hybrid approaches?
2. Data Isolation Granularity: Are all models tenant-scoped, or is selective scoping needed (e.g., TenantAware trait)?
3. Fallback Logic: What happens during tenant resolution failures? Is there a "public" tenant or error handling?
4. Performance: Are there benchmarks for query performance with 10K+ tenants? What indexing strategies are recommended?
5. Migration Path: How will existing data be retroactively assigned to tenants? Are there tools for bulk migration?
6. Compliance: Does the package support audit logging or tenant-specific access controls beyond isolation?
7. Customization: Can tenant resolution logic be extended (e.g., API key-based tenants)?

Integration Approach

Stack Fit

• Laravel Ecosystem: Ideal for Laravel 8+/Lumen applications. Compatible with:
  • Eloquent: Automatic tenant scoping via Tenancy::resolve().
  • Middleware: Integrates with Laravel’s middleware pipeline (e.g., TenantMiddleware).
  • Routing: Supports domain/subdomain-based routing natively.
• Non-Laravel Stacks: Not applicable—hard dependency on Laravel’s service container and routing.
• Alternatives: Compare with:
  • Stancl/Tenant: More mature, supports schema-per-tenant.
  • BeyondCode/Laravel-Permissions: For role-based tenant access.

Migration Path

1. Assessment Phase:
   • Audit existing tenant logic (if any) and identify gaps (e.g., missing tenant_id columns).
   • Define tenant resolution rules (domain/subdomain/path).
2. Setup:
   • Install package: composer require roberts/laravel-singledb-tenancy.
   • Publish config: php artisan vendor:publish --provider="Roberts\Tenancy\TenancyServiceProvider".
   • Configure tenancy.php (e.g., domain or subdomain resolution).
3. Database Schema:
   • Add tenant_id to all tenant-scoped tables (use migrations or manual ALTER).
   • Ensure tenant_id is indexed: ALTER TABLE users ADD INDEX tenant_id_idx(tenant_id).
4. Middleware:
   • Register TenantMiddleware in app/Http/Kernel.php:

     protected $middleware = [
         \Roberts\Tenancy\Middleware\TenantMiddleware::class,
     ];
     

5. Testing:
   • Mock tenant resolution in unit tests:

     Tenancy::impersonate(Tenant::find(1));
     

   • Test edge cases (invalid domains, concurrent requests).

Compatibility

• Laravel Version: Tested with Laravel 8+ (check composer.json constraints).
• PHP Version: Requires PHP 8.0+ (verify with roberts/laravel-singledb-tenancy).
• Database: MySQL/PostgreSQL/SQLite (no vendor-specific features).
• Conflicts:
  • Custom Model Booting: May override Tenancy::boot() if not careful.
  • Route Caching: Clear cached routes if adding tenant-specific domains post-install.

Sequencing

1. Phase 1: Proof of Concept
   • Set up a single tenant, verify isolation, and test current_tenant() helper.
2. Phase 2: Migration
   • Backfill tenant_id for existing data (batch process to avoid locks).
   • Update all Eloquent models to support tenant scoping.
3. Phase 3: Rollout
   • Deploy middleware and routing changes.
   • Monitor query performance and tenant resolution latency.
4. Phase 4: Optimization
   • Add tenant-specific indexes or query caching.
   • Implement tenant-specific connection pooling (if needed).

Operational Impact

Maintenance

• Package Updates: Monitor for breaking changes (MIT license allows forks if needed).
• Dependency Management: Ensure compatibility with Laravel core updates (e.g., Eloquent changes).
• Custom Logic: Extensions to tenant resolution may require maintenance if package evolves.

Support

• Debugging: Limited community support (0 stars). Debugging may rely on:
  • Package logs (Tenancy::debug()).
  • GitHub issues (if any exist).
• Common Issues:
  • Tenant resolution failures (e.g., misconfigured domains).
  • Query performance degradation (lack of proper indexing).
• Fallback Plan: Document manual tenant resolution bypass (e.g., Tenancy::setTenantId()) for critical paths.

Scaling

• Horizontal Scaling:
  • Stateless Middleware: Tenant resolution is stateless; works with load balancers.
  • Database Load: Single-DB tenancy may hit limits at scale (e.g., 100K+ tenants). Consider:
    • Read replicas with tenant-aware routing.
    • Sharding by tenant (requires custom logic).
• Performance Bottlenecks:
  • Query Scoping: Global tenant scopes add overhead to every query. Mitigate with:
    • Tenant-specific indexes (e.g., tenant_id + created_at).
    • Query caching (e.g., Redis for frequent tenant data).
  • Tenant Resolution: Domain lookups add latency. Pre-warm tenant cache if using API gateways.

Failure Modes

Ramp-Up

• Team Onboarding:
  • Developers: Train on:
    • Tenant-aware Eloquent queries.
    • Tenancy::impersonate() for debugging.
    • Middleware customization.
  • DevOps: Document:
    • Database indexing strategies.
    • Tenant resolution latency SLOs.
    • Rollback procedures.
• Documentation Gaps:
  • Create internal runbooks for:
    • Tenant migration steps.
    • Performance tuning (e.g., query optimization).
    • Disaster recovery (e.g., tenant data restoration).
• Training Materials:
  • Record a demo of tenant isolation in action.
  • Share examples of tenant-scoped queries and middleware extensions.