How can I set javaOptions in a custom sbt command - scala

Question

I am trying to add a custom command to SBT (using version 1.2.8 at the moment) to start my application with different javaOptions. I managed to create 3 separate tasks to accomplish this for three of the startup possibilities, but now I want to generalize this to allow any startup parameter.
So far I managed to create the following build.sbt, but the console output shows that the sbt runNode node3 still uses the original classpath as set on line 13 (run / javaOptions ++= Seq(...).
The run / javaOptions += s"-Djava.library.path=./target/native/$arg" on line 46 is ignored apparently.
import com.typesafe.sbt.SbtMultiJvm.multiJvmSettings
import com.typesafe.sbt.SbtMultiJvm.MultiJvmKeys.MultiJvm
import Dependencies._
lazy val `akka-crdt-features` = project
.in(file("."))
.settings(multiJvmSettings: _*)
.settings(
organization := "nl.about42.akkamavericks",
scalaVersion := "2.12.8",
Compile / scalacOptions ++= Seq("-deprecation", "-feature", "-unchecked", "-Xlog-reflective-calls", "-Xlint"),
Compile / javacOptions ++= Seq("-Xlint:unchecked", "-Xlint:deprecation"),
run / javaOptions ++= Seq("-Xms128m", "-Xmx1024m", "-Djava.library.path=./target/native"),
//run / javaOptions ++= Seq("-agentlib:hprof=heap=dump,format=b"),
libraryDependencies ++= akkaDependencies ++ otherDependencies,
run / fork := true,
Compile / run / mainClass := Some("nl.about42.akkamavericks.cluster.ClusterCrdtApp"),
// disable parallel tests
Test / parallelExecution := false,
licenses := Seq(("CC BY 4.0", url("https://creativecommons.org/licenses/by/4.0/"))),
commands ++= Seq(runNodeCommand),
Global / cancelable := true
)
.configs (MultiJvm)
// setup commands to run each individual node, using a separate folder for the extracted libsigar
lazy val runNode1 = taskKey[Unit]("Run node 1")
lazy val runNode2 = taskKey[Unit]("Run node 2")
lazy val runNode3 = taskKey[Unit]("Run node 3")
runNode1 / fork := true
runNode2 / fork := true
runNode3 / fork := true
runNode1 / javaOptions += "-Djava.library.path=./target/native/node1"
runNode2 / javaOptions += "-Djava.library.path=./target/native/node2"
runNode3 / javaOptions += "-Djava.library.path=./target/native/node3"
fullRunTask(runNode1, Compile, "nl.about42.akkamavericks.cluster.ClusterCrdtApp", "node1")
fullRunTask(runNode2, Compile, "nl.about42.akkamavericks.cluster.ClusterCrdtApp", "node2")
fullRunTask(runNode3, Compile, "nl.about42.akkamavericks.cluster.ClusterCrdtApp", "node3")
// setup command to start a single node, using separate folder for the extracted libsigar
// assumes sane node names that can be used as folder names
val runNodeAction: (State, String) => State = { (state, arg) =>
run / javaOptions += s"-Djava.library.path=./target/native/$arg"
val runCommand: Exec = Exec.apply(s"run $arg", state.source)
state.copy(
remainingCommands = runCommand +: state.remainingCommands
)
}
val runNodeCommand: Command = Command.single("runNode")(runNodeAction)
The output of sbt runNode node3 shows (relevant lines):
[error] no libsigar-amd64-linux.so in java.library.path: [./target/native]
[error] org.hyperic.sigar.SigarException: no libsigar-amd64-linux.so in java.library.path: [./target/native]
I expect it to mention ./target/native/node3.
My goal is to have just the sbt command definition, so I can call runNode [anyNodeName] and have SBT start my application with the appropriate classpath setting and startup argument.
Update:
I partially succeeded with the following:
val runNodeAction: (State, String) => State = { (state, arg) =>
val stateWithNewOptions = Project.extract(state).appendWithSession(
Seq(
run / javaOptions += s"-Djava.library.path=./target/native/$arg"
),
state
)
val runCommand: Exec = Exec.apply(s"run $arg", stateWithNewOptions.source)
stateWithNewOptions.copy(
remainingCommands = runCommand +: state.remainingCommands
)
}
But that leaves the classpath set to the latest run (does not revert back to the default).

Answer 1

With the help of Mario Galic (https://stackoverflow.com/a/54488121/2037054) who answered Conditional scalacSettings / settingKey, I managed to get it working:
// setup command to start a single node, using separate folder for the extracted libsigar
// assumes sane node names that can be used as folder names
val runNodeAction: (State, String) => State = { (state, arg) =>
val stateWithNewOptions = Project.extract(state).appendWithSession(
Seq(
run / javaOptions += s"-Djava.library.path=./target/native/$arg"
),
state
)
val (s, _) = Project.extract(stateWithNewOptions).runInputTask(Compile / run, s" $arg", stateWithNewOptions)
s
}
val runNodeCommand: Command = Command.single("runNode")(runNodeAction)