Core Concepts[Searchable] Attribute

[Searchable] Attribute

The [Searchable] attribute marks a grain state class for search indexing and links it to its grain interface.

Usage

[Searchable(typeof(IUserGrain))]
[GenerateSerializer]
public class UserState
{
    [Queryable]
    [Id(0)]
    public string Email { get; set; } = string.Empty;
}

Parameters

ParameterTypeDescription
grainTypeTypeThe grain interface this state belongs to (required)

Requirements

The grain interface must:

  1. Inherit from IGrainWithStringKey
  2. Be accessible from the state class
// Grain interface - must use string key
public interface IUserGrain : IGrainWithStringKey
{
    Task SetEmailAsync(string email);
}
 
// State class - linked via [Searchable]
[Searchable(typeof(IUserGrain))]
[GenerateSerializer]
public class UserState
{
    [Queryable]
    [Id(0)]
    public string Email { get; set; } = string.Empty;
}

What It Does

When you apply [Searchable] to a state class, the source generator creates:

  1. Entity class - An EF Core entity mirroring your queryable properties
  2. Search provider - Handles CRUD operations for the search index
  3. Search model - Enables type-safe LINQ queries
  4. Query extensions - Fluent API methods like Where()

Example

// Define your grain interface
public interface IProductGrain : IGrainWithStringKey
{
    Task SetDetailsAsync(string name, decimal price);
    Task<string> GetNameAsync();
}
 
// Mark state as searchable
[Searchable(typeof(IProductGrain))]
[GenerateSerializer]
public class ProductState
{
    [Queryable]
    [FullTextSearchable(Weight = 2.0)]
    [Id(0)]
    public string Name { get; set; } = string.Empty;
 
    [Queryable]
    [Id(1)]
    public decimal Price { get; set; }
 
    [Queryable]
    [Id(2)]
    public bool InStock { get; set; }
 
    // Not marked as [Queryable] - stored but not searchable
    [Id(3)]
    public string InternalNotes { get; set; } = string.Empty;
}

Generated Code

For the ProductState example above, the generator creates:

// Generated entity
public class ProductStateEntity : ISearchEntity
{
    public string GrainId { get; set; }
    public int Version { get; set; }
    public DateTime LastUpdated { get; set; }
 
    public string Name { get; set; }
    public decimal Price { get; set; }
    public bool InStock { get; set; }
}
 
// Generated search provider
public class ProductStateSearchProvider : SearchProviderBase<IProductGrain, ProductState, ProductStateEntity>
{
    // State-to-entity mapping
    // Query execution
}

Multiple Searchable States

You can have multiple searchable states in your application:

[Searchable(typeof(IUserGrain))]
public class UserState { /* ... */ }
 
[Searchable(typeof(IProductGrain))]
public class ProductState { /* ... */ }
 
[Searchable(typeof(IOrderGrain))]
public class OrderState { /* ... */ }

Each generates its own entity, provider, and query extensions.

Next Steps

Overview[Queryable] Attribute