向SBT13.x build.sbt添加任务

Question

我已经把这个添加到build.sbt中了

libraryDependencies += "com.typesafe.slick" %% "slick-codegen" % "2.1.0"

lazy val slickGenerate = TaskKey[Seq[File]]("slick code generation")

slickGenerate <<= slickGenerateTask 

lazy val slickGenerateTask = {
    (sourceManaged in Compile, dependencyClasspath in Compile, runner in Compile, streams) map { (dir, cp, r, s) =>
      val dbName = "dbname"
      val userName = "user"
      val password = "password"
      val url = s"jdbc:mysql://server:port/$dbName" 
      val jdbcDriver = "com.mysql.jdbc.Driver"
      val slickDriver = "scala.slick.driver.MySQLDriver"
      val targetPackageName = "models"
      val outputDir = (dir / dbName).getPath // place generated files in sbt's managed sources folder
      val fname = outputDir + s"/$targetPackageName/Tables.scala"
      println(s"\nauto-generating slick source for database schema at $url...")
      println(s"output source file file: file://$fname\n")
      r.run("scala.slick.codegen.SourceCodeGenerator", cp.files, Array(slickDriver, jdbcDriver, url, outputDir, targetPackageName, userName, password), s.log)
      Seq(file(fname))
    }
}

任务的代码本身并不令人兴奋。它只需要创建一个自动生成的scala源文件。问题是，sbt很好地启动，但是这个新任务显然没有被sbt识别，并且不能在sbt提示符中运行。对于任务定义的:=语法，我的运气也很差。现有的文件只是令人困惑。

如何在sbt提示符中提供这个新任务？

Answer 1

这行得通

libraryDependencies += "com.typesafe.slick" %% "slick-codegen" % "2.1.0"

lazy val slickGenerate = taskKey[Seq[File]]("slick code generation")

slickGenerate := {
  val dbName = "dbname"
  val userName = "user"
  val password = "password"
  val url = s"jdbc:mysql://server:port/$dbName"
  val jdbcDriver = "com.mysql.jdbc.Driver"
  val slickDriver = "scala.slick.driver.MySQLDriver"
  val targetPackageName = "models"
  val outputDir = ((sourceManaged in Compile).value / dbName).getPath // place generated files in sbt's managed sources folder
  val fname = outputDir + s"/$targetPackageName/Tables.scala"
  println(s"\nauto-generating slick source for database schema at $url...")
  println(s"output source file file: file://$fname\n")
  (runner in Compile).value.run("scala.slick.codegen.SourceCodeGenerator", (dependencyClasspath in Compile).value.files, Array(slickDriver, jdbcDriver, url, outputDir, targetPackageName, userName, password), streams.value.log)
  Seq(file(fname))
}

在sbt 0.13.x中，您不需要所有这些blabla map sameblabla样板。只需像(runner in Compile).value一样访问值-宏将为您完成其他一切。

> slickGenerate
[info] Updating {file:/Users/user/slick/}slick...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.

auto-generating slick source for database schema at jdbc:mysql://server:port/dbname...
output source file file: file:///Users/user/slick/target/scala-2.10/src_managed/main/dbname/models/Tables.scala

> help slickGenerate
slick code generation

谈到<<= --您的TaskKey是不正确的，请参阅定义：

def apply[T](label : scala.Predef.String, description : scala.Predef.String // not description

因此，旧的定义<<=使用"generate代码“作为标签，而新的:=使用代码指定的命令名称(新样式)，因此它使用"generate代码”作为文档。这看起来很奇怪，也不一致，但这是事实，部分原因是向后兼容性。

所以，正确的旧式版本是：

import sbt.Keys._

lazy val slickGenerate = TaskKey[Seq[File]]("slick-generate", "generate slick code")

slickGenerate <<= slickGenerateTask

def slickGenerateTask =
  (sourceManaged in Compile, dependencyClasspath in Compile, runner in Compile, streams) map { (dir, cp, r, s) =>
    ...
  }

它的工作方式与以前一样。注意，您必须使用"slickGenerate"，而不是“slickGenerate”，最后一个命令对“帮助”不起作用。

顺便说一句，您现在正在使用裸构建定义 --您可能希望切换到多项目.sbt定义，这是sbt，另请参阅推荐的。