Akka Streams programming basics

Before we develop some Akka Streams applications in this chapter, we will first take some baby steps to understand the Streams API very well.

Creating a Source

To create an Akka Stream's Source, we need to use one of its functions, such as single, by providing some input elements. For instance, create a Source that contains the numbers 1 to 10 as shown here:

val numbersSource = Source.single(1 to 10) 

If we add this code snippet to a Scala App and run it from your favorite IDE or using the sbt command, we don't see any output. This is because Akka Streams components are executed only when we run them manually:

package com.packt.publishing.akka.streams.hello 
import akka.stream.scaladsl.Source 
object AkkaStreamsBabyStepsApp extends App{ 
   val numbersSource = Source.single(1 to 10) 
} 

Similarly, we can create a Source from a String, Collection, Map, File, Database, and so on.

We can also create a Source using its apply method, as shown here:

val source = Source...