I'm trying to get an interactive shell into my Scala application. I'm using the following system:
Scala 2.10.0
sbt 0.12.2
Akka 2.1.0
sbt-lwjgl-plugin 3.1.4
and the following non-working code:
import akka.actor.Actor
import scala.tools.nsc.Settings
import scala.tools.nsc.interpreter.IMain
class TestActor extends Actor {
def receive => {
case _ => {
val settings = new Settings
settings.usejavacp.value = true
settings embeddedDefaults ActorSystem.getClass.getClassLoader
val repl = new IMain(settings)
repl.interpret("import java._") // working
repl.interpret("import scala._") // working
repl.interpret("import akka._") // not working
repl.interpret("import other.java.class.Bar") // not working
}
}
}
Sbt is set to fork := true. I've tried several settings and class path configurations, but didn't find a working configuration. Can someone give me a hint/solution for this problem?
Have you tried to re-import all classpath with absolute path?
val settings = new Settings
settings.usejavacp.value = true
val classLoader = Thread.currentThread.getContextClassLoader
classLoader.asInstanceOf[URLClassLoader].getURLs.map(url => new File(url.toURI).getAbsolutePath).foreach {
jarPath =>
println(s"adding into Scala SDK classpath : ${jarPath}")
settings.bootclasspath.append(jarPath)
settings.classpath.append(jarPath)
}
Related
I'm write a SBT task, which can output the dependencies information, grouped by project (say a SBT project has multi projects)
I know there is a sbt-dependency-graph plugin, but I can use it directly, because I want to generate a json file, but that plugin just output the dependency tree to console, without returning an data object, I can't easily get the data I want.
I found the update task returns a UpdateReport which contains a lot of information I want, but it only belong to the current project. In command line, if I want to know the information of all project, I can manually show all the projects by projects command, and view them one by one by someproject/update.
But how to do the same in a SBT task? I tried:
val reports = projects.toList.map(prj => (update in prj).value)
It reports:
[error] /Users/me/workspace/sbt-test/project/Build.scala:51: Illegal dynamic reference: prj
[error] val reports = projects.toList.map(prj => (update in prj).value)
[error] ^
[error] one error found
How to fix it?
More code:
import sbt._
import sbt.Keys._
object DemoBuild extends Build {
lazy val allUpdate = taskKey[Unit]("show update reports of all projects")
lazy val core = project
lazy val web = project
lazy val allUpdateDef = allUpdate := {
val reports = projects.toList.map(prj => (update in prj).value)
println(reports)
}
lazy val root = (project in file("."))
.settings(
allUpdateDef
)
}
After checking the document: http://www.scala-sbt.org/0.13/docs/Tasks.html, I found the solution:
import sbt._
import sbt.Keys._
object DemoBuild extends Build {
lazy val groupByProject: Def.Initialize[Task[(String, UpdateReport)]] =
Def.task {
(thisProject.value.id, (update in thisProject).value)
}
lazy val filter = ScopeFilter(inAnyProject, inAnyConfiguration)
updateByProject := {
val subProjects = groupByProject.all(filter).value.map { case ( projectName, updateReport) =>
...
}
}
}
I hit a MissingRequirementError when I try to invoke scaladoc from within an sbt task.
Using any version of sbt 0.13.x, start with this build.sbt:
val scaladoc = taskKey[Unit]("run scaladoc")
scaladoc := {
import scala.tools.nsc._
val settings = new doc.Settings(error => print(error))
settings.usejavacp.value = true
val docFactory = new doc.DocFactory(new reporters.ConsoleReporter(settings), settings)
val universe = docFactory.makeUniverse(Left((sources in Compile).value.map(_.absolutePath).toList))
}
Then run sbt scaladoc, and behold (during makeUniverse):
[info] Set current project to test (in build file:...)
scala.reflect.internal.MissingRequirementError: object scala.annotation.Annotation in compiler mirror not found.
at scala.reflect.internal.MissingRequirementError$.signal(MissingRequirementError.scala:16)
at scala.reflect.internal.MissingRequirementError$.notFound(MissingRequirementError.scala:17)
at scala.reflect.internal.Mirrors$RootsBase.getModuleOrClass(Mirrors.scala:48)
What is wrong here? I've already tried fork := true and different combinations of sbt/scala versions to no avail.
It seems you need to provide scala-library (and indeed, any other dependencies) directly to the DocFactory.
scaladoc := {
import scala.tools.nsc._
val settings = new doc.Settings(error => print(error))
val dependencyPaths = (update in Compile).value
.select().map(_.absolutePath).mkString(java.io.File.pathSeparator)
settings.classpath.append(dependencyPaths)
settings.bootclasspath.append(dependencyPaths)
val docFactory = new doc.DocFactory(new reporters.ConsoleReporter(settings), settings)
val universe = docFactory.makeUniverse(Left((sources in Compile).value.map(_.absolutePath).toList))
}
I've build a litte object, which can interpret scala code on the fly and catches a value out of it.
object Interpreter {
import scala.tools.nsc._
import scala.tools.nsc.interpreter._
class Dummy
val settings = new Settings
settings.usejavacp.value = false
settings.embeddedDefaults[Dummy] // to make imain useable with sbt.
val imain = new IMain(settings)
def run(code: String, returnId: String) = {
this.imain.beQuietDuring{
this.imain.interpret(code)
}
val ret = this.imain.valueOfTerm(returnId)
this.imain.reset()
ret
}
}
object Main {
def main(args: Array[String]) {
println(Interpreter.run("val x = 1", "x"))
}
}
In a pure sbt environment or called by the scala interpreter this code works fine! But if I run this in a simple play (version 2.2.2) application, it gets a null pointer at val ret = this.imain.valueOfTerm(returnId).
play uses also a modified sbt, therefor it should probably work. What does play do that this code doesn't work anymore? Any ideas how to get this code to work in play?
Note
That's the used build.sbt:
name := "Test"
version := "1.0"
scalaVersion := "2.10.3"
libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value
Alternatively I tried this implementation, but it doesen't solve the problem either:
object Interpreter2 {
import scala.tools.nsc._
import scala.tools.nsc.interpreter._
import play.api._
import play.api.Play.current
val settings: Settings = {
lazy val urls = java.lang.Thread.currentThread.getContextClassLoader match {
case cl: java.net.URLClassLoader => cl.getURLs.toList
case _ => sys.error("classloader is not a URLClassLoader")
}
lazy val classpath = urls map {_.toString}
val tmp = new Settings()
tmp.bootclasspath.value = classpath.distinct mkString java.io.File.pathSeparator
tmp
}
val imain = new IMain(settings)
def run(code: String, returnId: String) = {
this.imain.beQuietDuring {
this.imain.interpret(code)
}
val ret = this.imain.valueOfTerm(returnId)
this.imain.reset()
ret
}
}
Useful links I found to make this second implementation:
scala.tools.nsc.IMain within Play 2.1
How to set up classpath for the Scala interpreter in a managed environment?
https://groups.google.com/forum/#!topic/scala-user/wV86VwnKaVk
https://github.com/gourlaysama/play-repl-example/blob/master/app/REPL.scala#L18
https://gist.github.com/mslinn/7205854
After spending a few hours on this issue myself, here is a solution that I came up with. It works both inside SBT and outside. It is also expected to work in a variety of managed environments (like OSGi):
private def getClasspathUrls(classLoader: ClassLoader, acc: List[URL]): List[URL] = {
classLoader match {
case null => acc
case cl: java.net.URLClassLoader => getClasspathUrls(classLoader.getParent, acc ++ cl.getURLs.toList)
case c => LOGGER.error("classloader is not a URLClassLoader and will be skipped. ClassLoader type that was skipped is " + c.getClass)
getClasspathUrls(classLoader.getParent, acc)
}
}
val classpathUrls = getClasspathUrls(this.getClass.getClassLoader, List())
val classpathElements = classpathUrls map {url => url.toURI.getPath}
val classpath = classpathElements mkString java.io.File.pathSeparator
val settings = new Settings
settings.bootclasspath.value = classpath
val imain = new IMain(settings)
// use imain to interpret code. It should be able to access all your application classes as well as dependent libraries.
It's because play uses the "fork in run" feature from sbt. This feature starts a new JVM and this causes that this failure appears:
[info] Failed to initialize compiler: object scala.runtime in compiler mirror not found.
[info] ** Note that as of 2.8 scala does not assume use of the java classpath.
[info] ** For the old behavior pass -usejavacp to scala, or if using a Settings
[info] ** object programatically, settings.usejavacp.value = true.
See: http://www.scala-sbt.org/release/docs/Detailed-Topics/Forking
I'm writing an SBT Plugin that adds a Command and would like users to be able to configure this Command by setting variables in their build.sbt. What is the simplest way to achieve this?
Here is an simplified example of what the Plugin looks like:
import sbt.Keys._
import sbt._
object MyPlugin extends Plugin {
override lazy val settings = Seq(commands += Command.args("mycommand", "myarg")(myCommand))
def myCommand = (state: State, args: Seq[String]) => {
//Logic for command...
state
}
}
I would like someone to be able to add the follow to their build.sbt file:
newSetting := "light"
How do I make this available as a String variable from inside the myCommand Command above?
Take a look at the example here: http://www.scala-sbt.org/release/docs/Extending/Plugins.html#example-plugin
In this example, a task and setting are defined:
val newTask = TaskKey[Unit]("new-task")
val newSetting = SettingKey[String]("new-setting")
val newSettings = Seq(
newSetting := "test",
newTask <<= newSetting map { str => println(str) }
)
A user of your plugin could then provide their own value for the newSetting setting in their build.sbt:
newSetting := "light"
EDIT
Here's another example, closer to what you're going for:
Build.scala:
import sbt._
import Keys._
object HelloBuild extends Build {
val newSetting = SettingKey[String]("new-setting", "a new setting!")
val myTask = TaskKey[State]("my-task")
val mySettings = Seq(
newSetting := "default",
myTask <<= (state, newSetting) map { (state, newSetting) =>
println("newSetting: " + newSetting)
state
}
)
lazy val root =
Project(id = "hello",
base = file("."),
settings = Project.defaultSettings ++ mySettings)
}
With this configuration, you can run my-task at the sbt prompt, and you'll see newSetting: default printed to the console.
You can override this setting in build.sbt:
newSetting := "modified"
Now, when you run my-task at the sbt prompt, you'll see newSetting: modified printed to the console.
EDIT 2
Here's a stand-alone version of the example above: https://earldouglas.com/ext/stackoverflow.com/questions/17038663/
I've accepted #James's answer as it really helped me out. I moved away from using a Commands in favour of a Task (see this mailing list thread). In the end my plugin looked something like this:
package packge.to.my.plugin
import sbt.Keys._
import sbt._
object MyPlugin extends Plugin {
import MyKeys._
object MyKeys {
val myTask = TaskKey[Unit]("runme", "This means you can run 'runme' in the SBT console")
val newSetting = SettingKey[String]("newSetting")
}
override lazy val settings = Seq (
newSetting := "light",
myTask <<= (state, newSetting) map myCommand
)
def myCommand(state: State, newSetting: String) {
//This code runs when the user types the "runme" command in the SBT console
//newSetting is "light" here unless the user overrides in their build.sbt (see below)
state.log.info(newSetting)
}
}
To override the newSetting in the build.sbt of a project that uses this plugin:
import packge.to.my.plugin.MyKeys._
newSetting := "Something else"
The missing import statement had me stuck for a while!
I googled a lot and am totally stuck now. I know, that there are similar questions but please read to the end. I have tried all proposed solutions and none did work.
I am trying to use the IMain class from scala.tools.nsc within a Play 2.1 project (Using Scala 2.10.0).
Controller Code
This is the code, where I try to use the IMain in a Websocket. This is only for testing.
object Scala extends Controller {
def session = WebSocket.using[String] { request =>
val interpreter = new IMain()
val (out,channel) = Concurrent.broadcast[String]
val in = Iteratee.foreach[String]{ code =>
interpreter.interpret(code) match {
case Results.Error => channel.push("error")
case Results.Incomplete => channel.push("incomplete")
case Results.Success => channel.push("success")
}
}
(in,out)
}
}
As soon as something gets sent over the Websocket the following error gets logged by play:
Failed to initialize compiler: object scala.runtime in compiler mirror not found.
** Note that as of 2.8 scala does not assume use of the java classpath.
** For the old behavior pass -usejavacp to scala, or if using a Settings
** object programatically, settings.usejavacp.value = true.
Build.scala
object ApplicationBuild extends Build {
val appName = "escalator"
val appVersion = "1.0-SNAPSHOT"
val appDependencies = Seq(
"org.scala-lang" % "scala-compiler" % "2.10.0"
)
val main = play.Project(appName, appVersion, appDependencies).settings(
)
}
What I have tried so far
All this didn't work:
I have included fork := true in the Build.scala
A Settings object with:
embeddedDefaults[MyType]
usejavacp.value = true
The soultion proposed as answer to Question Embedded Scala REPL inherits parent classpath
I dont know what to do now.
The problem here is that sbt doesnt add scala-library to the class path.
The following workaround works.
First create a folder lib in the top project directory(the parent of app,conf etc) and copy there the scala-library.jar
Then you can use the following code to host an interpreter :
val settings = new Settings
settings.bootclasspath.value +=scala.tools.util.PathResolver.Environment.javaBootClassPath + File.pathSeparator + "lib/scala-library.jar"
val in = new IMain(settings){
override protected def parentClassLoader = settings.getClass.getClassLoader()
}
val res = in.interpret("val x = 1")
The above creates the bootclasspath by adding to the java class the scala library. It's not a problem with play framework it comes from the sbt. The same problem occures for any scala project when it runs with sbt. Tested with a simple project. When it runs from eclipse its works fine.
EDIT: Link to sample project demonstrating the above.`
I wonder if the reflect jar is missing. Try adding this too in appDependencies.
"org.scala-lang" % "scala-reflect" % "2.10.0"