My SBT prompt config

README.md

My customized SBT shell prompt

A heavily customied SBT shell prompt that shows the following information:

• a handy marker to show you are in SBT
• the current Git status (a clean working directory is green, a dirty one is yellow)
• the current project, including the root project of a multi-project build

Requirements

This plugin uses some special icon-like characters (the segment separator and the Git branch icon) that are not supported by most fonts. In order for this theme to render correctly, you will need a Powerline-patched font.

You can also just replace these characters with less high-maintenance ones.

How to use

This plugin depends on the sbt-git plugin so, before doing anything else, add it to your plugins.sbt file.

Then just copy the ShellPrompt.scala file to the project folder of your project and reload/restart SBT.

Make sure your file is saved using UTF-8 encoding to prevent the special

Customization

If you want to customize the colors used in this theme, have a look at these handy references:

• Ansi escape code reference
• Graphical overview of the Ansi 256 color codes

Future plans

I might get around to turning this into a full public SBT plugin but, knowing myself and my history with planning these things, don't hold your breath ;)

Credits

Initial idea shamelessly stolen from the Play framework, all credits to them! Heavily customized aftwards based on my lightly customized version of the Oh-My-Zsh "agnoster" theme.

Enjoy!
Age (@agemooij)

example-screenshot.png

ShellPrompt.scala

import sbt._
import Keys._

/*
 * Initial idea shamelessly stolen from the Play framework, all credits to them!
 * Heavily customized aftwards based on my lightly customized version of the
 * Oh-My-Zsh "agnoster" theme.
 *
 * This theme uses some special icon-like characters (the segment separator
 * and the Git branch icon) that are not supported by most fonts. In order
 * for this theme to render correctly, you will need a
 * [Powerline-patched font](https://github.com/Lokaltog/powerline-fonts).
 *
 * If you want to customize the colors used in this theme, have a look at
 * these handy references:
 *
 * - [Ansi escape code reference](http://misc.flogisoft.com/bash/tip_colors_and_formatting)
 * - [Graphical overview of the Ansi 256 color codes](http://www.calmar.ws/vim/color-output.png)
 *
 * Enjoy!
 * Age (@agemooij)
 */
object ShellPrompt extends Plugin with Ansi256ColorSupport with PromptSegmentSupport with GitSupport {
  override def settings = Seq(
    shellPrompt := { state =>
      val extracted = Project.extract(state)

      import extracted._
      import com.typesafe.sbt.SbtGit._

      val project = currentRef.project
      val root = rootProject(currentRef.build)
      val path = if (project == root) project else s"${root}/${project}"

      val branch = " " + extracted.get(GitKeys.gitCurrentBranch)

      prompt(
        List(
          PromptSegment("SBT", 26, 235),
          if (isGitDirty(state, extracted)) PromptSegment(branch, 214, 235) else PromptSegment(branch, 34, 235),
          PromptSegment(path, 235, 250)
        ),
        ""
      )
    }
  )
}


trait GitSupport {
  import com.typesafe.sbt.SbtGit._
  def isGitDirty(state: State, extracted: Extracted): Boolean = {
    val (_, runner) = extracted.runTask(GitKeys.gitRunner, state)
    val dir = extracted.get(baseDirectory)
    val result = runner("diff-index", "HEAD", "--")(dir, NoOpSbtLogger)

    !result.trim.isEmpty
  }
}


case class PromptSegment(text: String, bg: Int, fg: Int)


trait PromptSegmentSupport extends Ansi256ColorSupport {
  def prompt(segments: Seq[PromptSegment], separator: String): String = {
    val combined = segments.foldLeft("") { (combined, segment) =>
      if (combined.isEmpty)
        s"${combined}${bg(segment.bg)}${fg(segment.fg)} ${segment.text} ${fg(segment.bg)}"
      else
        s"${combined}${bg(segment.bg)}${separator}${fg(segment.fg)} ${segment.text} ${fg(segment.bg)}"
    }

    s"${combined}${defaultBg}${separator}${defaultFg} "
  }
}

trait AnsiColorSupport {
  val defaultFg = "\u001b[39m"
  val defaultBg = "\u001b[49m"
  val resetColors = defaultBg + defaultFg

  lazy val isANSISupported = {
    Option(System.getProperty("sbt.log.noformat")).map(_ != "true").orElse {
      Option(System.getProperty("os.name"))
        .map(_.toLowerCase)
        .filter(_.contains("windows"))
        .map(_ => false)
    }.getOrElse(true)
  }
}

trait Ansi256ColorSupport extends AnsiColorSupport {
  def fg(code: Int): String = {
    require(code >= 0 && code <= 255)
    s"\u001b[38;5;${code}m"
  }

  def bg(code: Int): String = {
    require(code >= 0 && code <= 255)
    s"\u001b[48;5;${code}m"
  }

  /** Little util for potential theme writers to get a quick overview of the supported ANSI256 color escape sequences. */
  def printSupportedColors: Unit = {
    for (i <- 0 to 255) {
      println(s"${fg(i)} foreground (${i}) $defaultFg ${bg(i)} background (${i}) $defaultBg")
    }
  }
}

object NoOpSbtLogger extends Logger {
  def trace(t: => Throwable): Unit = {}
  def success(message: => String): Unit = {}
  def log(level: Level.Value, message: => String): Unit = {}
}