Type Members

1.  trait AcquireRelease[-R, +E, A] extends Scoped[R, E]

   A special form of Scoped for convenience.

   A special form of Scoped for convenience.

   When using ZLayer.derive with a type that implements AcquireRelease, the provided acquire and release methods will be automatically utilized as the lifecycle hooks.

   Note

   This trait's lifecycle hooks are specifically designed to work with ZLayer.derive. Using it outside this context won't inherently attach any lifecycle behaviors to the type.

2.  trait Default[+A] extends AnyRef

   Provides a default way to construct or provide an instance of type A.

   Provides a default way to construct or provide an instance of type A.

   Used during ZLayer derivation to resolve dependencies. If an implicit ZLayer.Derive.Default[A] instance exists for a type, it signifies that a default value can be used, bypassing the dependency in the ZLayer environment.

   Note

   When type-annotating the implicit val, ensure it's in the form Default.WithContext[R, E, A] rather than just Default[A] to ensure correct type inference and dependency resolution during ZLayer derivation.

3.  trait Scoped[-R, +E] extends AnyRef

   Defines a resourceful effect that will be attached to the lifetime of the ZLayer derived by ZLayer.derive.

   Defines a resourceful effect that will be attached to the lifetime of the ZLayer derived by ZLayer.derive.

   The 'resourceful' effect might be a background task, a lock file, or etc., that can be managed by Scope.

   If scoped fails during resource acquisition, the entire ZLayer initialization process fails.

   Note

   This trait is specifically designed to work with ZLayer.derive. Using it outside this context won't inherently attach any resourceful behaviors to the type.

   class ThirdPartyService(connection: Connection) extends ZLayer.Derive.Scoped[Any, Nothing] {
   
     // Repeats health check every 10 seconds in background during the layer's lifetime
     override def scoped(implicit trace: Trace): ZIO[Scope, Nothing, Any] =
       connection.healthCheck
         .ignoreLogged
         .repeat(Schedule.spaced(10.seconds))
         .forkScoped
   }
   
   object ThirdPartyService {
     // `ZLayer.Derive.Scoped` should be used with `ZLayer.derive`
     val layer = ZLayer.derive[ThirdPartyService]
   }