distage-framework-api/izumi.distage.roles.model/RoleService

RoleService

izumi.distage.roles.model.RoleService

trait RoleService[+F[_]] extends AbstractRole[F]

A type of role representing a persistent service.

Will be kept running forever up until the application is interrupted.

Attributes

Graph
Supertypes: trait AbstractRole[F]
class Object
trait Matchable
class Any

Members list

Concise view

Value members

Abstract methods

Returns a izumi.distage.model.definition.Lifecycle with the start/shutdown of a service described by its acquire/release actions. The acquired service will be kept alive until the application is interrupted or is otherwise finished, then the specified release action of the Lifecycle will run for cleanup.

Attributes

Note:

Resource initialization must be finite. Application startup won't progress until the acquire phase of the returned Lifecycle is finished. You may start a separate thread / fiber, etc during resource initialization. All the shutdown logic has to be implemented in the resource finalizer.

Example:

Often start is implemented using the izumi.distage.model.definition.Lifecycle.fork_ method to spawn a daemon fiber running the service in background.

import izumi.distage.roles.model.RoleService
import izumi.functional.bio.{F, IO2}
import logstage.LogIO2
import logstage.LogIO2.log
final class HelloService[F[+_, +_]: IO2: LogIO2] extends RoleService[F] {
 def start(roleParameters: RawEntrypointParams, freeArgs: Vector[String]): Lifecycle[F[Nothing, _], Unit] = {
   Lifecycle.fork_(helloServer).void
 }
 val helloServer: F[Throwable, Unit] = {
   (for {
     name <- F.syncThrowable { Console.in.readLine() }
     _    <- log.info(s"Hello $name!")
   } yield ()).forever
 }
}

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