在Scala Cat中的后台线程上运行IO

Question

def backGroundTask:IO[Unit]={
IO
{
//Time consuming task
}
}

How to execute this task eagerly on a background thread?

Answer 1

You can use ContextShift.evalOn :

def backGroundTask = IO {
      Thread.currentThread()
}

val contextShift: ContextShift[IO] = IO.contextShift(ExecutionContext.global)

val ec = ExecutionContext.fromExecutor(Executors.newCachedThreadPool()) //create other execution context

println(backGroundTask.unsafeRunSync()) // will print Thread[main,5,main]
println(contextShift.evalOn(ec)(backGroundTask).unsafeRunSync()) //will print Thread[pool-1-thread-1,5,main]