What's required to have sbt build with Akka?

Question

I am trying to use scala -akka from sbt.

My sbt file looks as follows:

name := "hello"

version := "1.0"

scalaVersion := "2.9.1"

resolvers += "akka" at "http://repo.akka.io/snapshots"

libraryDependencies ++= Seq(
  "com.codahale"      % "simplespec_2.9.0-1" % "0.4.1",
  "com.typesafe.akka" % "akka-stm"           % "2.0-SNAPSHOT" 
)

my code:

import akka._

object HelloWorld {
  def main(args: Array[String]) {
    println("Hello, world!")
  }
}

When I do sbt compile, I get

]# **sbt compile**
[info] Set current project to default-91c48b (in build file:/var/storage1/home/test_user/dev_scala/hello/)
[info] Compiling 1 Scala source to /var/storage1/home/test_user/dev_scala/hello/target/scala-2.9.2/classes...
[error] /var/storage1/home/test_user/dev_scala/hello/src/main/scala/hw.scala:3: not found: object akka
[error] import akka._
[error]        ^
[error] one error found
[error] (compile:compile) Compilation failed
[error] Total time: 3 s, completed May 22, 2013 8:59:08 PM

Please advice.

EDIT2: based on comments bellow. here is the new sbt file

name := "hello"
version := "1.0"
scalaVersion := "2.9.1"

resolvers += "akka" at "http://repo.akka.io/snapshots"

libraryDependencies ++= Seq(
"com.typesafe.akka" %% "akka-actor" % "2.1.4",
  "com.codahale" % "simplespec_2.9.0-1" % "0.4.1",
  "com.typesafe.akka" % "akka-stm" % "2.0-SNAPSHOT" ,
  "com.typesafe.akka" %% "akka-actor"    % "2.2-M3",
"com.typesafe.akka" %% "akka-slf4j"    % "2.2-M3",
"com.typesafe.akka" %% "akka-remote"   % "2.2-M3",
"com.typesafe.akka" %% "akka-testkit"  % "2.2-M3"% "test"
)

any ideas ?

Solution 1

You didn't have all right dependencies for your project.

You have add this one "com.typesafe.akka" %% "akka-actor" % "2.0.5". This one is the main dependency with the core modules for akka. Also it's better to add the following ones for your akka project:

"com.typesafe.akka" %% "akka-actor"    % "2.0.5",
"com.typesafe.akka" %% "akka-slf4j"    % "2.0.5",
"com.typesafe.akka" %% "akka-remote"   % "2.0.5",
"com.typesafe.akka" %% "akka-agent"    % "2.0.5", 
"com.typesafe.akka" %% "akka-testkit"  % "2.0.5"% "test"

And to use actors you should import akka.actor._

Updated

Ok, this build file works for me

name := "hello"

version := "1.0"

scalaVersion := "2.10.1"

libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor"   % "2.2-M3",
  "com.typesafe.akka" %% "akka-slf4j"   % "2.2-M3",
  "com.typesafe.akka" %% "akka-remote"  % "2.2-M3",
  "com.typesafe.akka" %% "akka-agent"   % "2.2-M3",
  "com.typesafe.akka" %% "akka-testkit" % "2.2-M3" % "test"
)

Don't forget to reload and update your project in sbt

Solution 2

Your akka-actor dependency absolutely CAN NOT be a different version than your other dependencies. And any dependencies you add absolutely CAN NOT be reliant on different versions of akka either or you'll have a very messed up dependency tree.

And you may as well use current versions if you're starting out. Coltrane 2.2-M3 is current at time of writing.

You can add some more akka libs as needed... But this is a basic starting point based on a real project that we run in prod:

name := "app"

organization := "com.yourorg"

version := "0.0.1-SNAPSHOT"

scalaVersion := "2.10.1"

scalacOptions ++= Seq("-unchecked", "-deprecation")

resolvers ++= Seq(
    "Typesafe Repository" at "http://repo.typesafe.com/typesafe/releases/"
)


libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor" % "2.2-M3",
  "com.typesafe.akka" %% "akka-slf4j" % "2.2-M3",
  "com.typesafe.akka" %% "akka-testkit" % "2.2-M3"
)

Solution 3

UPDATED ON 24.03.2019

To use Akka Actors you need the following dependencies:

For sbt:

libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor" % "2.5.21",
  "com.typesafe.akka" %% "akka-testkit" % "2.5.21" % Test
)

For Gradle:

dependencies {
  compile group: 'com.typesafe.akka', name: 'akka-actor_2.12', version: '2.5.21'
  testCompile group: 'com.typesafe.akka', name: 'akka-testkit_2.12', version: '2.5.21'
}

For Maven:

<dependency>
  <groupId>com.typesafe.akka</groupId>
  <artifactId>akka-actor_2.12</artifactId>
  <version>2.5.21</version>
</dependency>
<dependency>
  <groupId>com.typesafe.akka</groupId>
  <artifactId>akka-testkit_2.12</artifactId>
  <version>2.5.21</version>
  <scope>test</scope>
</dependency>

For more Informations and Dependency-Codesnippets regarding Akka Cluster, Akka Streams, Akka Http, Alpakka etc check: https://akka.io/docs/

Comments

[4lex1v]

@Hector123 i can't even run sbt with your build.sbt there is no such module at "http://repo.akka.io/snapshots". How did you run this build file?

[4lex1v]

@Hector123 i've updated dependencies for akka, it works for me

[CruncherBigData]

I changed it to resolvers += "Typesafe Repository" at "repo.typesafe.com/typesafe/releases" per the akka docs

[4lex1v]

@Hector123 Which version of Scala and Akka do you need to use?

[CruncherBigData]

scala 2.10.1 and the latest from akka

[4lex1v]

@Hector123 I've updated your build, just copy paste this to your build.sbt and type reload and the update in your sbt console

[JasonG]

Old dependencies in original section. Use current versions of akka and scala for new projects (2.10.1 and akka 2.2-M3 at time of writing)