如何依赖"当前"配置中的设置

Question

如何声明2个自定义sbt设置,比如A和B,在Global配置范围内定义B ,其内容依赖于A,在几个配置范围中以不同方式定义A,使得每个配置中B的结果值不同虽然B只定义一次？

考虑下面的示例targetHost,与remote其他配置中的定义不同,scriptContent具体取决于:

object MyBuild  extends Build {

    lazy val remote = config("remote") describedAs ("configuration for remote environement ")

    lazy val targetHost = settingKey[String]("private hostname of master server")

    lazy val scriptContent = settingKey[String]("Some deployment script")

    lazy val root: Project = Project("meme", file(".")).
    settings(
        name := "hello",

        targetHost := "localhost",
        targetHost in remote := "snoopy",

        scriptContent := s"""
            # some bash deployment here
            /usr/local/uberDeploy.sh ${targetHost.value}
        """
    )    
}

我想scriptContent有两个配置范围不同的值,但因为它依赖于targetHost在Global范围内的值总是相同的:

> scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh localhost
[info]
> remote:scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh localhost
[info] 

而我想获得以下内容:

> scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh localhost
[info]
> remote:scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh snoopy
[info] 

Answer 1

找到了！我的问题实际上是重复的（抱歉...），最相关的答案在这里：How can i make an SBT key see settings for the current configuration？

=> 我们需要多次应用设置，每个范围一次，以强制重新评估 的内容scriptSetting：

import sbt._
import sbt.Keys._

object MyBuild  extends Build {

    lazy val remote = config("remote") describedAs ("configuration for remote environement ")

    lazy val targetHost = settingKey[String]("private hostname of master server")

    lazy val scriptContent = settingKey[String]("Some deployment script")

    lazy val scriptSettings = Seq(
        scriptContent := s"""
            # some bash deployment here
            /usr/local/uberDeploy.sh ${targetHost.value}
        """
    )

    lazy val root: Project = Project("meme", file("."))
    .settings(
        name := "hello",    
        targetHost := "localhost",
        targetHost in remote := "snoopy"
        )    
    .settings(scriptSettings: _*)
    .settings(inConfig(remote)(scriptSettings) :_*)
}

产生预期结果：

> scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh localhost
[info]
> remote:scriptContent
[info]
[info]             # some bash deployment here
[info]             /usr/local/uberDeploy.sh snoopy
[info]
>