Site Profile Attributes

Site Profile relies on a set of custom attributes and Roslyn source generators to automate Dependency Injection registration and boilerplate code generation.

[GenerateSiteProfile] — The Core Attribute

This is the most important attribute. It marks a partial class as a Site Profile and triggers the generation of the RegisterServices method.

Usage

[GenerateSiteProfile(SiteIds.BRAVO, typeof(BravoOrderContext))]
public partial class BravoSiteProfile : ISiteProfile
{
    public string SiteId => SiteIds.BRAVO;
}

Parameters

Parameter	Type	Default	Description
siteId	string	Required	Unique site identifier (e.g., "BRAVO")
dbContextType	Type	Required	The site's DbContext type. Use typeof(object) for aggregate projects
SkipDbContextRegistration	bool	false	Set to true for projects without a DbContext (aggregates, gateways)

When SkipDbContextRegistration = true:

• No AddSiteDbContext<T>() call is generated
• typeof(object) is used as the DbContext type parameter (placeholder)
• Only RegisterAdditionalServices() is called for custom DI

What it Generates

The source generator creates a partial implementation of your profile class containing:

1. RegisterServices: A method that registers the site's DbContext, any behaviors, and calls RegisterAdditionalServices.
2. SiteIds Constants: Automatically adds the new SiteId to a generated constants class.
3. SiteDbContextTypeRegistry: Updates a global registry used by migration runners to find all site contexts.

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[SiteProfileAlias] — Reusing Services

Use this attribute when a new site is identical in logic to an existing site (usually the DEFAULT site) but needs its own database or connection string.

Usage

[SiteProfileAlias(SiteIds.DEFAULT)]
[GenerateSiteProfile(SiteIds.CHARLIE, typeof(CharlieOrderContext))]
public partial class CharlieSiteProfile : ISiteProfile { ... }

Effect

The generator emits code that aliases all keyed services registered for the TargetSiteId (e.g., DEFAULT) to also be available under the current SiteId (e.g., CHARLIE). This eliminates the need to manually re-register shared services.

Schema Divergence Risk

Alias sites share all service implementations with their source site — including ISiteColumnMap, SiteSqlBuilder queries, and DbContext configurations. This means:

• If the alias site's database has different column names than the source site, all Dapper queries will generate wrong SQL
• If the alias site is missing tables or columns that the source site expects, queries will fail at runtime
• If the alias site has extra columns not in the source site, those columns will be silently ignored

Rule: Only use [SiteProfileAlias] when the alias site's database schema is identical to the source site's schema. Different connection strings and data are fine — different schemas are not.

If schemas differ, create a full site profile with its own column map and DbContext:

// Wrong — Delta has different column names but aliases Default
[SiteProfileAlias(SiteIds.DEFAULT)]
[GenerateSiteProfile(SiteIds.DELTA, typeof(DeltaOrderContext))]
public partial class DeltaSiteProfile : ISiteProfile { }

// Correct — Delta gets its own column map and service overrides
[GenerateSiteProfile(SiteIds.DELTA, typeof(DeltaOrderContext))]
public partial class DeltaSiteProfile : ISiteProfile { }

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[SiteProfileBehavior] — Cross-Cutting Concerns

Behaviors allow you to apply reusable DI registrations (like auditing, caching, or quota enforcement) to multiple sites.

Usage

[SiteProfileBehavior(typeof(SiteAuditBehavior))]
[SiteProfileBehavior(typeof(SiteQuotaBehavior))]
[GenerateSiteProfile(SiteIds.ALPHA, typeof(AlphaOrderContext))]
public partial class AlphaSiteProfile : ISiteProfile { ... }

Implementing a Behavior

A behavior must implement the ISiteProfileBehavior interface.

public class SiteAuditBehavior : ISiteProfileBehavior
{
    public void Apply(IServiceCollection services, IConfiguration configuration, string siteId)
    {
        services.AddKeyedScoped<IAuditLogger, SiteAuditLogger>(siteId);
    }
}

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[GenerateSiteGrpcFacade] — Unified gRPC Clients

In "Aggregate" projects that need to call both shared and site-specific gRPC services, this attribute generates a unified facade client.

Usage

[GenerateSiteGrpcFacade(
    SharedClient = typeof(OrderServiceClient),
    ExtendClients = new[] { typeof(TciOrderServiceClient) })]
public partial interface ITciOrderClient { }

Effect

The generator creates a concrete TciOrderClientFacade that combines all RPC methods from both clients into a single interface. It automatically dispatches calls to the correct underlying client based on the current site context.

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[SiteGrpcService] — Per-Site Proto Registration

Mark a gRPC service implementation as site-specific. This is useful when a site has a completely different .proto contract.

Usage

[SiteGrpcService(SiteIds.TCI)]
public class TciOrderGrpcService : TciOrder.TciOrderBase 
{
    // Implementation of TCI-specific gRPC contract
}

Effect

The MapSiteGrpcServices() extension in Program.cs will automatically discover and route requests to this service when the TCI site code is detected.

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[SiteColumn] — Property-Level Column Mapping

An alternative to fluent API overrides in OnModelCreating(). Decorate entity properties directly with column metadata:

public class BravoOrder
{
    public long Id { get; set; }

    [SiteColumn(Name = "BOOKING_NUMBER", MaxLength = 25)]
    public string? BookingNo { get; set; }

    [SiteColumn(IsRequired = true, DefaultValue = "N")]
    public string? Status { get; set; }

    // No attribute → uses UPPER_SNAKE_CASE convention: CONTAINER_NO
    public string? ContainerNo { get; set; }
}

Parameters

Parameter	Type	Description
Name	string?	Override column name
MaxLength	int?	Column max length constraint
IsRequired	bool	NOT NULL constraint
DefaultValue	string?	SQL default value
HasColumnType	string?	Database type override (e.g., "decimal(18,4)")
Ignore	bool	Completely exclude property from EF mapping

Applying

protected override void ConfigureSiteSpecific(ModelBuilder modelBuilder)
{
    modelBuilder.ApplySiteColumnOverrides<BravoOrder>(SiteIds.BRAVO);
}

When to use [SiteColumn] vs fluent API

• [SiteColumn]: Best when column differences are simple (name, length, required) and you want them visible on the entity
• Fluent API: Best for complex configurations (indexes, relationships, computed columns)
• Both can be used together — fluent API overrides [SiteColumn] if both are set

Package: Muonroi.EntityFrameworkCore.Configuration

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Attribute Summary Table

Attribute	Target	Purpose
[GenerateSiteProfile]	Class	Generates RegisterServices() and registers DbContext.
[SiteProfileAlias]	Class	Reuses all keyed services from a target site.
[SiteProfileBehavior]	Class	Applies reusable DI logic (Auditing, Quotas, etc.).
[GenerateSiteGrpcFacade]	Interface	Combines shared and site-specific gRPC clients.
[SiteGrpcService]	Class	Registers a site-specific gRPC service endpoint.
[SiteColumn]	Property	Direct EF Core column mapping on entity properties.

Source Files

• src/Muonroi.Tenancy.SiteProfile/GenerateSiteProfileAttribute.cs
• src/Muonroi.Tenancy.SiteProfile/SiteProfileAliasAttribute.cs
• src/Muonroi.Tenancy.SiteProfile/ISiteProfileBehavior.cs
• src/Muonroi.Tenancy.SiteProfile.Grpc/SiteGrpcServiceAttribute.cs
• src/Muonroi.Tenancy.SiteProfile.Grpc/GenerateSiteGrpcFacadeAttribute.cs
• src/Muonroi.EntityFrameworkCore.Configuration/SiteColumnAttribute.cs

Next Steps

• Site Column Map Guide — Mapping properties to columns.
• SQL Builder Guide — Building site-aware queries.
• gRPC Multi-Site Patterns — Deep dive into gRPC dispatching.