SaasSuite.Core

Core abstractions and contracts for building multi-tenant SaaS applications in .NET.

Overview

SaasSuite.Core provides the foundational interfaces, models, and services for implementing multi-tenancy in .NET applications. It defines the core contracts for tenant resolution, isolation policies, and tenant context management without imposing specific implementation details.

Features

• Tenant Resolution: Flexible tenant identification from various sources (HTTP headers, JWT claims, subdomains)
• Tenant Context Management: Strongly-typed tenant context with extensible properties
• Isolation Policies: Support for multiple isolation levels (Shared, Dedicated, Hybrid)
• Tenant Lifecycle: Tenant storage, retrieval, and management operations
• Maintenance Windows: Schedule and manage per-tenant maintenance periods
• Telemetry Integration: Enrich monitoring and logging with tenant context

Installation

dotnet add package SaasSuite.Core

Quick Start

1. Register Core Services

var builder = WebApplication.CreateBuilder(args); // Register SaasSuite.Core services builder.Services.AddSaasCore(); var app = builder.Build(); // Add tenant resolution middleware app.UseSaasResolution(); app.Run();

2. Configure Tenant Resolution

using SaasSuite.Core.Interfaces; using SaasSuite.Core.Services; // Resolve tenant from HTTP headers builder.Services.AddSingleton<ITenantResolver>(sp => { var httpContextAccessor = sp.GetRequiredService<IHttpContextAccessor>(); return new HttpHeaderTenantResolver(httpContextAccessor); });

3. Access Tenant Context

using SaasSuite.Core; using SaasSuite.Core.Interfaces; app.MapGet("/api/tenant-info", (ITenantAccessor tenantAccessor) => { var tenant = tenantAccessor.TenantContext; if (tenant == null) return Results.BadRequest("No tenant context"); return Results.Ok(new { tenantId = tenant.TenantId.Value, tenantName = tenant.Name }); });

Core Concepts

TenantId

Strongly-typed identifier for tenants with implicit string conversions:

TenantId tenantId = new TenantId("tenant-123"); string id = tenantId; // Implicit conversion

TenantContext

Holds the current tenant information:

public class TenantContext { public TenantId TenantId { get; set; } public string Name { get; set; } public string Identifier { get; set; } public Dictionary<string, object> Properties { get; set; } }

Isolation Levels

Define how tenant data is isolated:

• None: No isolation (single-tenant scenarios)
• Shared: Logical isolation in shared database
• Dedicated: Physical isolation per tenant
• Hybrid: Mix of shared and dedicated resources

public class MyIsolationPolicy : IIsolationPolicy { public IsolationLevel GetIsolationLevel(TenantId tenantId) { // Enterprise tenants get dedicated databases if (IsEnterpriseTenant(tenantId)) return IsolationLevel.Dedicated; return IsolationLevel.Shared; } public Task<bool> ValidateAccessAsync( TenantId tenantId, string resourceId, CancellationToken cancellationToken = default) { // Validate tenant can access resource return Task.FromResult(true); } }

Key Interfaces

ITenantResolver

Resolves tenant ID from the current execution context:

public interface ITenantResolver { Task<TenantId?> ResolveTenantIdAsync(CancellationToken cancellationToken = default); }

ITenantStore

Persistence operations for tenant data:

public interface ITenantStore { Task<TenantInfo?> GetByIdAsync(TenantId tenantId, CancellationToken cancellationToken = default); Task<TenantInfo?> GetByIdentifierAsync(string identifier, CancellationToken cancellationToken = default); Task SaveAsync(TenantInfo tenant, CancellationToken cancellationToken = default); Task RemoveAsync(TenantId tenantId, CancellationToken cancellationToken = default); }

ITenantAccessor

Access point for the current tenant context:

public interface ITenantAccessor { TenantContext? TenantContext { get; } }

Maintenance Windows

Schedule maintenance periods for tenants:

using SaasSuite.Core.Interfaces; public class MaintenanceController : ControllerBase { private readonly IMaintenanceService _maintenanceService; public MaintenanceController(IMaintenanceService maintenanceService) { _maintenanceService = maintenanceService; } [HttpPost("schedule")] public async Task<IActionResult> ScheduleMaintenance( string tenantId, DateTime startTime, int durationMinutes) { await _maintenanceService.ScheduleMaintenanceAsync( new TenantId(tenantId), startTime, TimeSpan.FromMinutes(durationMinutes)); return Ok(); } [HttpGet("is-under-maintenance")] public async Task<IActionResult> CheckMaintenance(string tenantId) { var isUnderMaintenance = await _maintenanceService .IsUnderMaintenanceAsync(new TenantId(tenantId)); return Ok(new { underMaintenance = isUnderMaintenance }); } }

Telemetry Enrichment

Enrich logs and metrics with tenant context:

public class TenantTelemetryEnricher : ITelemetryEnricher { public void Enrich(IDictionary<string, object> telemetryData, TenantContext context) { telemetryData["TenantId"] = context.TenantId.Value; telemetryData["TenantName"] = context.Name; telemetryData["IsolationLevel"] = context.Properties .TryGetValue("IsolationLevel", out var level) ? level : "Unknown"; } }

Multi-Framework Support

SaasSuite.Core targets:

• .NET 6.0 (LTS)
• .NET 7.0
• .NET 8.0 (LTS)
• .NET 9.0
• .NET 10.0

Related Packages

• SaasSuite.EfCore: Entity Framework Core integration
• SaasSuite.Features: Feature flag management
• SaasSuite.Quotas: Quota enforcement
• SaasSuite.Seats: Seat limit enforcement

License

This package is licensed under the Apache License 2.0. See the LICENSE file in the repository root for details.