tpolecat / linebacker

Finally Tagless Blocking Implementation

Linebacker

Enabling Functional Blocking where you need it.

Quick Start

To use linebacker in an existing SBT project with Scala 2.11 or a later version, add the following dependency to your build.sbt:

libraryDependencies += "io.chrisdavenport" %% "linebacker" % "<version>"

Examples

First some imports

import scala.concurrent.ExecutionContext.Implicits.global
import fs2.Stream
import cats.effect._
import cats.implicits._
import io.chrisdavenport.linebacker.Linebacker
import io.chrisdavenport.linebacker.contexts.Executors

Creating And Evaluating Pool Behavior

val getThread = IO(Thread.currentThread().getName)

object ThreadNameExample {
  val checkRun = Executors.unbound[IO] // Create Executor
    .map(Linebacker.fromExecutorService[IO](_)) // Create Linebacker From Executor
    .flatMap { implicit linebacker => // Raise Implicitly
      Stream.eval(
        Linebacker[IO].block(getThread) // Block On Linebacker Pool Not Global
      ) ++
      Stream.eval(getThread) // Running On Global
    }
    .evalMap(threadName => IO(println(threadName)))
    .compile
    .drain
}
ThreadNameExample.checkRun.unsafeRunSync

Dual Contexts Are Also Very Useful

import scala.concurrent.ExecutionContext
import io.chrisdavenport.linebacker.DualContext

Executors.unbound[IO].map(blockingExecutor =>
  DualContext.fromContexts[IO](global,  ExecutionContext.fromExecutorService(blockingExecutor))
)