NBB.Data.EntityFramework.MultiTenancy

NBB.Data.EntityFramework.MultiTenancy

The package NBB.Data.EntityFramework.MultiTenancy helps implementing a multi-tenant data access solution using Entity Framework.

NuGet install

dotnet add package NBB.Data.EntityFramework.MultiTenancy

Philosophy

When it comes to multi-tenant data access, there are 3 strategies:

• Database per tenant: in this case, the only thing you have to do, is to provide a connection string per tenant, when registering a DbContext. This strategy offers the biggest isolation level, but is the most expensive one

• Shared database: when using this strategy, multi-tenant tables are partitioned by a TenantId column. This package provides extensions for EF objects, in order to configure both a shadow state property TenantId and a global query filter with the value set to ITenantContext.GetTenantId, so that user queries can remain tenancy agnostic. This strategy offers a poor isolation level so it must be used with caution!

• A mix of shared and dedicated databases: some tenants may be shared in the same database while others have dedicated database instances

This package supports all 3 strategies stated above, so that you can write tenancy ignorant queries

Multi-tenant DbContext configuration

• to configure a multi-tenant entity, you need to call IsMultiTenant() inside entity configuration, like so:

public class MyEntityConfiguration: IEntityTypeConfiguration<TodoTask>
{
    public void Configure(EntityTypeBuilder<MyEntity> builder)
    {
        builder
            .ToTable("MyEntities")
            .IsMultiTenant()
            .HasKey(x => x.MyEntityId);
    }
}

• you can derive from MultiTenantDbContext in order to use multi-tenant capabilities:

public class MyDbContext : MultiTenantDbContext
{
    public DbSet<MyEntity> MyEntities { get; set; }
    public TodoDbContext(DbContextOptions<MyDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfiguration(new MyEntityConfiguration());
            
        base.OnModelCreating(modelBuilder);
    }
}

• if you cannot derive from MultiTenantDbContext, you can add multi-tenant capabilities to your existing DbContext by overriding the methods SaveChangesAsync and SaveChanges , like so:

public override Task<int> SaveChangesAsync(bool acceptAllChangesOnSuccess, CancellationToken cancellationToken = default)
{
    this.SetTenantIdFromContext();
   
    return base.SaveChangesAsync(acceptAllChangesOnSuccess, cancellationToken);
}

public override int SaveChanges(bool acceptAllChangesOnSuccess)
{
    this.SetTenantIdFromContext();

    return base.SaveChanges(acceptAllChangesOnSuccess);
}

DbContext container registration

When registering multi-tenant DbContext you can use the ITenantDatabaseConfigService abstractions in order to get the tenant's connection string. You also need to call the UseMultitenancy extension:

services.AddDbContext<KycDbContext>((serviceProvider, options) =>
{
    var tenantConfiguration = serviceProvider.GetRequiredService<ITenantConfiguration>();
    var connectionString = tenantConfiguration.GetConnectionString("DefaultConnection");
    
    options
        .UseSqlServer(connectionString)
        .UseMultitenancy(serviceProvider);
});

Be aware that when using a multi-tenant dbContext, you cannot use the DbContextPool