如何使 SBT 任务依赖于同一 SBT 项目中定义的模块？

Question

我在多模块 SBT 项目中有模块 A 和模块 B。我想为模块 B 编写一个资源生成器任务，它调用模块 A 的代码。一种方法是从 project/ 下的模块 A 中提取所有代码，但这是不可行的，因为模块 A 很大，我会喜欢将其保留在原处（参见）。我如何在 SBT 中执行此操作？

其次，是否有可能完全摆脱模块 B，即我希望模块 A 的资源生成器任务实际上从模块 A 调用代码，但模块 A 是根模块并且不存在于 SBT 中 project?

注意：这个问题不是这个问题的重复：Defining sbt task that invokes method from project code? 因为那个问题决定将代码移到 SBT 的项目中，这是我在这里特别要避免的事情。

Answer 1

我认为我正在做类似于您在以下项目中的第一部分的事情：我的module gen is the equivalent of your module A, and my module core相当于您的模块B。未经测试，结构大致如下：

// taking inspiration from
// 
lazy val ugenGenerator = TaskKey[Seq[File]]("ugen-generate", "Generate UGen class files")

lazy val gen = Project(id = "gen", base = file("gen")) ...

lazy val core = Project(id = "core", base = file("core"))
  .settings(
    sourceGenerators in Compile <+= ugenGenerator in Compile,
    ugenGenerator in Compile := {
      val src   = (sourceManaged       in Compile        ).value
      val cp    = (dependencyClasspath in Runtime in gen ).value
      val st    = streams.value
      runUGenGenerator(description.value, outputDir = src, 
        cp = cp.files, log = st.log)
    }
  )

def runUGenGenerator(name: String, outputDir: File, cp: Seq[File],
                    log: Logger): Seq[File] = {
  val mainClass   = "my.class.from.Gen"
  val tmp         = java.io.File.createTempFile("sources", ".txt")
  val os          = new java.io.FileOutputStream(tmp)

  log.info(s"Generating UGen source code in $outputDir for $name")

  try {
    val outs  = CustomOutput(os)
    val fOpt  = ForkOptions(javaHome = None, outputStrategy = Some(outs), bootJars = cp,
        workingDirectory = None, connectInput = false)
    val res: Int = Fork.scala(config = fOpt,
      arguments = mainClass :: "-d" :: outputDir.getAbsolutePath :: Nil)

    if (res != 0) {
      sys.error(s"UGen class file generator failed with exit code $res")
    }
  } finally {
    os.close()
  }
  val sources = scala.io.Source.fromFile(tmp).getLines().map(file).toList
  tmp.delete()
  sources
}

这在 sbt 0.13 中有效，但我还没有时间弄清楚为什么它在 1.x 中不起作用。

顺便问一下，如何在不使用弃用语法的情况下编写 sourceGenerators in Compile <+= ugenGenerator in Compile？

Answer 2

基于@0__上面的回答，这是我的简化版本：

  /**
    * Util to run the main of a sub-module from within SBT
    *
    * @param cmd The cmd to run with the main class with args (if any)
    * @param module The sub-module
    */
  def runModuleMain(cmd: String, module: Reference) = Def.task {
    val log = streams.value.log
    log.info(s"Running $cmd ...")
    val classPath = (fullClasspath in Runtime in module).value.files
    val opt = ForkOptions(bootJars = classPath, outputStrategy = Some(LoggedOutput(log)))
    val res = Fork.scala(config = opt, arguments = cmd.split(' '))
    require(res == 0, s"$cmd exited with code $res")
  }

然后您可以调用它：

resourceGenerators in Compile += Def.taskDyn {
  val dest = (resourceManaged in Compile).value
  IO.createDirectory(dest)
  runModuleMain(
    cmd = "com.mycompany.foo.ResourceGen $dest $arg2 $arg3 ...",
    module = $referenceToModule // submodule containing com.mycompany.foo.ResourceGen
  ).taskValue
  dest.listFiles()
}

有可以做到这一点：

resourceGenerators in Compile += Def.taskDyn {
  val dest = (resourceManaged in Compile).value
  IO.createDirectory(dest)      
  Def.task {
    val cmd = "com.mycompany.foo.ResourceGen $dest $arg2 $arg3 ..."        
    (runMain in Compile).toTask(" " + $cmd).value 
    dest.listFiles()
  }
}.taskValue

如何使 SBT 任务依赖于同一 SBT 项目中定义的模块？

How to make a SBT task depend on a module defined in the same SBT project?

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