生成用于编译和测试的资源

Question

我打算根据模板和 sbt 设置生成资源。 Compile 和 Test 应该有不同的 sbt 设置。模板位于project/resources/hdfs/*.xml。从 sbt-dev gitter 聊天中，我得到了使用 Setting 和 inConfig 的建议，但我无法让它工作。

到目前为止的代码：

val hdfsNamenode = settingKey[String]("Namenode for the HDFS access")

def genHdfsConfigs: Setting[_] =
  hdfsNamenode := {
    resourceGenerators += Def.task {
      val files = ((baseDirectory.value / "project" / "resources" / "hdfs" ) * "*.xml").get
      files.foreach({ hdfsTemplate =>
        val config = IO.read(hdfsTemplate).replace("{{namenode}}", hdfsNamenode.value)
        IO.write(resourceManaged.value / hdfsTemplate.getName, config)
      })
      files.toSeq
    }.taskValue
  }

hdfsNamenode in Test := "localhost"
hdfsNamenode in Compile := "172.31.32.228"

def allHdfsNamenodeConfigs: Seq[Setting[_]] =
  inConfig(Compile)(Seq(hdfsNamenode)) ++ inConfig(Test)(Seq(hdfsNamenode))

错误：

[error]  found   : sbt.Def.Setting[Seq[sbt.Task[Seq[java.io.File]]]]
[error]  required: String
[error]       resourceGenerators += Def.task {
[error]                          ^

[error]  found   : sbt.SettingKey[String]
[error]  required: sbt.Def.Setting[_]
[error]     inConfig(Compile)(Seq(hdfsNamenode)) ++ inConfig(Test)(Seq(hdfsNamenode))
[error]        

下一次迭代，我不知道如何在Compile/Test 范围内获取hdfsNameNode，而不是在非范围内。

lazy val hdfsNameNode = settingKey[String]("Namenode for the HDFS access")

val genHdfsConfig = Def.task {
  val files = ((baseDirectory.value / "project" / "templates" / "resources" / "hdfs" ) * "*.xml").get
  files.map({ hdfsTemplate =>
    val config = IO.read(hdfsTemplate).replace("{{namenode}}", hdfsNameNode.value)
    val outputPath = resourceManaged.value / hdfsTemplate.getName
    IO.write(outputPath, config)
    outputPath
  })
}

Seq(
    hdfsNameNode := "undefined", // Only this one is accepted
    hdfsNameNode in Test := "localhost",
    hdfsNameNode in Compile := "172.31.32.228",
    resourceGenerators in Compile += genHdfsConfig.taskValue,
    resourceGenerators in Test += genHdfsConfig.taskValue
  )

当前（丑陋的）解决方案：

val hdfsTestNameNode = "localhost"
val hdfsMainNameNode = "172.31.32.228"

val hdfsNameNode = settingKey[String]("Namenode for the HDFS access")

val genTestHdfsConfig = Def.task {
  val files = ((baseDirectory.value / "project" / "templates" / "resources" / "hdfs" ) * "*.xml").get
  files.map({ hdfsTemplate =>
    val config = IO.read(hdfsTemplate).replace("{{namenode}}", (hdfsNameNode in Test).value)
    val outputPath = resourceManaged.value / hdfsTemplate.getName
    IO.write(outputPath, config)
    outputPath
  })
}

val genCompileHdfsConfig = Def.task {
  val files = ((baseDirectory.value / "project" / "templates" / "resources" / "hdfs" ) * "*.xml").get
  files.map({ hdfsTemplate =>
    val config = IO.read(hdfsTemplate).replace("{{namenode}}", (hdfsNameNode in Compile).value)
    val outputPath = resourceManaged.value / hdfsTemplate.getName
    IO.write(outputPath, config)
    outputPath
  })
}

Seq(
  hdfsNameNode in Test := hdfsTestNameNode,
  hdfsNameNode in Compile := hdfsMainNameNode,
  resourceGenerators in Compile += genCompileHdfsConfig.taskValue,
  resourceGenerators in Test += genTestHdfsConfig.taskValue
 )

Answer 1

在定义资源生成器时只需将配置作为参数传递。

val hdfsTestNameNode = "localhost"
val hdfsMainNameNode = "172.31.32.228"

val hdfsNameNode = settingKey[String]("Namenode for the HDFS access")

def genHdfsConfig(cfg: Configuration) = Def.task {
  val files = ((baseDirectory.value / "project" / "templates" / "resources" / "hdfs" ) * "*.xml").get
  files.map({ hdfsTemplate =>
    val config = IO.read(hdfsTemplate).replace("{{namenode}}", (hdfsNameNode in cfg).value)
    val outputPath = (resourceManaged in cfg).value / hdfsTemplate.getName
    IO.write(outputPath, config)
    outputPath
  })
}

Seq(
  hdfsNameNode in Test := hdfsTestNameNode,
  hdfsNameNode in Compile := hdfsMainNameNode,
  resourceGenerators in Compile += genHdfsConfig(Compile).taskValue,
  resourceGenerators in Test += genHdfsConfig(Test).taskValue
)

不想指定范围两次？只需再重构一点。

val hdfsTestNameNode = "localhost"
val hdfsMainNameNode = "172.31.32.228"

val hdfsNameNode = settingKey[String]("Namenode for the HDFS access")

def addHdfsConfigGenerator(cfg: Configuration) = {
  inConfig(cfg) {
    val hdfsConfigGenerator = Def.task {
      val files = ((baseDirectory.value / "project" / "templates" / "resources" / "hdfs" ) * "*.xml").get
      files.map({ hdfsTemplate =>
        val config = IO.read(hdfsTemplate).replace("{{namenode}}", (hdfsNameNode in cfg).value)
        val outputPath = (resourceManaged in cfg).value / hdfsTemplate.getName
        IO.write(outputPath, config)
        outputPath
      })
    }
    resourceGenerators += hdfsConfigGenerator.taskValue
  } last
}

Seq(
  hdfsNameNode in Test := hdfsTestNameNode,
  hdfsNameNode in Compile := hdfsMainNameNode,
  addHdfsConfigGenerator(Compile),
  addHdfsConfigGenerator(Test)
)