scala - 在任务中运行任务并在 sbt 中评估其结果

Question

我有兴趣编写一个任务来创建我的项目的启动器，该项目不再涉及 sbt。幸好 sbt 知道所有信息，所以我可以创建自己的启动器。在交互模式下，这四个命令向我显示了创建启动器所需的所有信息，但它们只是将它们打印出来，我无法进一步处理它们

show java-options
show unmanaged-jars
show managed-classpath

我想进一步处理这三个任务的结果，但我知道我不知道该怎么做。wiki 中的任务定义非常混乱，<<= 运算符更是如此。

Answer 1

创建任务并不多。我假设您查看了有关它的wiki，但没有理解某些内容。我想你会做这样的例子：

val stringTask = TaskKey[String]("string-task")
stringTask <<= (sampleTask, intTask) map { (sample: Int, intValue: Int) =>
    "Sample: " + sample + ", int: " + intValue
}

该<<=方法简单地说，定义stringTask取决于其他任务。

另一方面，也许你需要一个 Runner，而不是一个 Task。

不幸的是，编写一个跑步者并不是那么简单。我在这个项目上。这是它的定义：

class MyRunner(subproject: String, config: ForkScalaRun) extends sbt.ScalaRun {
  def run(mainClass: String, classpath: Seq[File], options: Seq[String], log: Logger): Option[String] = {
    log.info("Running " + subproject + " " + mainClass + " " + options.mkString(" "))

    val javaOptions = classpathOption(classpath) ::: mainClass :: options.toList
    val strategy = config.outputStrategy getOrElse LoggedOutput(log)
    val process =  Fork.java.fork(config.javaHome,
                                  config.runJVMOptions ++ javaOptions,
                                  config.workingDirectory,
                                  Map.empty,
                                  config.connectInput,
                                  strategy)
    def cancel() = {
      log.warn("Run canceled.")
      process.destroy()
      1
    }
    val exitCode = try process.exitValue() catch { case e: InterruptedException => cancel() }
    processExitCode(exitCode, "runner")
  }
  private def classpathOption(classpath: Seq[File]) = "-classpath" :: Path.makeString(classpath) :: Nil
  private def processExitCode(exitCode: Int, label: String) = {
    if(exitCode == 0) None
    else Some("Nonzero exit code returned from " + label + ": " + exitCode)
  }
}

它被这样使用：

runner in Compile in run <<= (thisProject, taskTemporaryDirectory, scalaInstance, baseDirectory, javaOptions, outputStrategy, javaHome, connectInput) map {
  (tp, tmp, si, base, options, strategy, javaHomeDir, connectIn) =>
    new MyRunner(tp.id, ForkOptions(scalaJars = si.jars, javaHome = javaHomeDir, connectInput = connectIn, outputStrategy = strategy,
      runJVMOptions = options, workingDirectory = Some(base)) )
}