Using Akka Dispatchers for Handling Futures - scala

Question

I have a Spray based HTTP Service. I have a stream that runs inside this HTTP application. Now since this stream does a lot of I/O, I decided to use a separate thread pool. I looked up the Akka documentation to see what I could do so that my thread pool is configurable. I came across the Dispatcher concept in Akka. So I tried to use it as below in my application.conf:
akka {
io-dispatcher {
# Dispatcher is the name of the event-based dispatcher
type = Dispatcher
# What kind of ExecutionService to use
executor = "fork-join-executor"
# Configuration for the fork join pool
fork-join-executor {
# Min number of threads to cap factor-based parallelism number to
parallelism-min = 2
# Parallelism (threads) ... ceil(available processors * factor)
parallelism-factor = 2.0
# Max number of threads to cap factor-based parallelism number to
parallelism-max = 10
}
# Throughput defines the maximum number of messages to be
# processed per actor before the thread jumps to the next actor.
# Set to 1 for as fair as possible.
throughput = 20
}
}
In my Actor, I tried to lookup this configuration as:
context.system.dispatchers.lookup("akka.io-dispatcher")
When I ran my service, I get the following error:
[ERROR] [05/03/2016 12:59:08.673] [my-app-akka.actor.default-dispatcher-2] [akka://my-app/user/myAppSupervisorActor] Dispatcher [akka.io-dispatcher] not configured
akka.ConfigurationException: Dispatcher [akka.io-dispatcher] not configured
at akka.dispatch.Dispatchers.lookupConfigurator(Dispatchers.scala:99)
at akka.dispatch.Dispatchers.lookup(Dispatchers.scala:81)
My questions are:
Is this io-dispatcher thread pool that I create, is it meant to be only used for Actor's? My intention was to use this thread pool for my streams which gets instantiated by one of the Actor. I then pass this thread pool to my stream.
How could I create an ExecutionContext by just loading the dispatcher from the application.conf? Should I use any specific library that would read my configuration for the thread pool and give me an ExecutionContext?

Answer 1

The configuration is correct. All You need to do is to pass the loaded configuration file to the Akka ActorSystem like:
ActorSystem("yourActorSystem", ConfigFactory.load())