From 6dde86fbdca07cd4c306a85e1d48532ca99a20bf Mon Sep 17 00:00:00 2001
From: Gary Coady <gary@lyranthe.org>
Date: Sun, 22 Jun 2014 18:49:45 +0100
Subject: [PATCH] Support EXPOSE [port] ... for Docker

Docker allows the ability to share ports between containers, if the ports
are listed in the configuration for the Docker image. This commit adds a
dockerExposedPorts setting which adds the appropriate line.
---
 .../sbt/packager/docker/DockerPlugin.scala    | 26 +++++++++++++------
 .../typesafe/sbt/packager/docker/Keys.scala   |  1 +
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/main/scala/com/typesafe/sbt/packager/docker/DockerPlugin.scala b/src/main/scala/com/typesafe/sbt/packager/docker/DockerPlugin.scala
index bbd0827a1..3ac806b00 100644
--- a/src/main/scala/com/typesafe/sbt/packager/docker/DockerPlugin.scala
+++ b/src/main/scala/com/typesafe/sbt/packager/docker/DockerPlugin.scala
@@ -8,8 +8,8 @@ import sbt._
 trait DockerPlugin extends Plugin with UniversalPlugin {
   val Docker = config("docker") extend Universal
 
-  private[this] final def makeDockerContent(dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, name: String) = {
-    Dockerfile(
+  private[this] final def makeDockerContent(dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, name: String, exposedPorts: Seq[Int]) = {
+    val dockerCommands = Seq(
       Cmd("FROM", dockerBaseImage),
       Cmd("MAINTAINER", maintainer),
       Cmd("ADD", "files /"),
@@ -18,12 +18,21 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
       Cmd("USER", daemonUser),
       ExecCmd("ENTRYPOINT", "bin/%s" format name),
       ExecCmd("CMD")
-    ).makeContent
+    )
+
+    val exposeCommand: Option[CmdLike] = {
+      if (exposedPorts.isEmpty)
+        None
+      else
+        Some(Cmd("EXPOSE", exposedPorts.mkString(" ")))
+    }
+
+    Dockerfile(dockerCommands ++ exposeCommand: _*).makeContent
   }
 
   private[this] final def generateDockerConfig(
-    dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, normalizedName: String, target: File) = {
-    val dockerContent = makeDockerContent(dockerBaseImage, dockerBaseDirectory, maintainer, daemonUser, normalizedName)
+    dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, normalizedName: String, exposedPorts: Seq[Int], target: File) = {
+    val dockerContent = makeDockerContent(dockerBaseImage, dockerBaseDirectory, maintainer, daemonUser, normalizedName, exposedPorts)
 
     val f = target / "Dockerfile"
     IO.write(f, dockerContent)
@@ -53,6 +62,7 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
       daemonUser := "daemon",
       publishArtifact := false,
       defaultLinuxInstallLocation := "/opt/docker",
+      dockerExposedPorts := Seq(),
       dockerPackageMappings <<= (sourceDirectory) map { dir =>
         MappingsHelper contentOf dir
       },
@@ -65,9 +75,9 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
           contextDir
       },
       dockerGenerateConfig <<=
-        (dockerBaseImage, defaultLinuxInstallLocation, maintainer, daemonUser, normalizedName, target) map {
-          case (dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, target) =>
-            generateDockerConfig(dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, target)
+        (dockerBaseImage, defaultLinuxInstallLocation, maintainer, daemonUser, normalizedName, dockerExposedPorts, target) map {
+          case (dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, target) =>
+            generateDockerConfig(dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, target)
         }
     ))
 }
diff --git a/src/main/scala/com/typesafe/sbt/packager/docker/Keys.scala b/src/main/scala/com/typesafe/sbt/packager/docker/Keys.scala
index 5665e1fd6..ea6eb838f 100644
--- a/src/main/scala/com/typesafe/sbt/packager/docker/Keys.scala
+++ b/src/main/scala/com/typesafe/sbt/packager/docker/Keys.scala
@@ -10,6 +10,7 @@ trait DockerKeys {
   val dockerPackageMappings = TaskKey[Seq[(File, String)]]("docker-package-mappings", "Generates location mappings for Docker build.")
 
   val dockerBaseImage = SettingKey[String]("dockerBaseImage", "Base image for Dockerfile.")
+  val dockerExposedPorts = SettingKey[Seq[Int]]("dockerExposedPorts", "Ports exposed by Docker image")
 }
 
 object Keys extends DockerKeys {