Support Docker volumes.

src/main/scala/com/typesafe/sbt/packager/docker/DockerPlugin.scala

@@ -8,7 +8,7 @@ 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, exposedPorts: Seq[Int]) = {
+  private[this] final def makeDockerContent(dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, name: String, exposedPorts: Seq[Int], exposedVolumes: Seq[String]) = {
     val dockerCommands = Seq(
       Cmd("FROM", dockerBaseImage),
       Cmd("MAINTAINER", maintainer),
@@ -27,12 +27,27 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
         Some(Cmd("EXPOSE", exposedPorts.mkString(" ")))
     }
 
-    Dockerfile(dockerCommands ++ exposeCommand: _*).makeContent
+    // If the exposed volume does not exist, the volume is made available
+    // with root ownership. This may be too strict for some directories,
+    // and we lose the feature that all directories below the install path
+    // can be written to by the binary. Therefore the directories are
+    // created before the ownership is changed.
+    val volumeCommands: Seq[CmdLike] = {
+      if (exposedVolumes.isEmpty)
+        Seq()
+      else
+        Seq(
+          ExecCmd("RUN", Seq("mkdir", "-p") ++ exposedVolumes: _*),
+          ExecCmd("VOLUME", exposedVolumes: _*)
+        )
+    }
+
+    Dockerfile(volumeCommands ++ exposeCommand ++ dockerCommands: _*).makeContent
   }
 
   private[this] final def generateDockerConfig(
-    dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, normalizedName: String, exposedPorts: Seq[Int], target: File) = {
-    val dockerContent = makeDockerContent(dockerBaseImage, dockerBaseDirectory, maintainer, daemonUser, normalizedName, exposedPorts)
+    dockerBaseImage: String, dockerBaseDirectory: String, maintainer: String, daemonUser: String, normalizedName: String, exposedPorts: Seq[Int], exposedVolumes: Seq[String], target: File) = {
+    val dockerContent = makeDockerContent(dockerBaseImage, dockerBaseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, exposedVolumes)
 
     val f = target / "Dockerfile"
     IO.write(f, dockerContent)
@@ -63,6 +78,7 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
       publishArtifact := false,
       defaultLinuxInstallLocation := "/opt/docker",
       dockerExposedPorts := Seq(),
+      dockerExposedVolumes := Seq(),
       dockerPackageMappings <<= (sourceDirectory) map { dir =>
         MappingsHelper contentOf dir
       },
@@ -75,9 +91,9 @@ trait DockerPlugin extends Plugin with UniversalPlugin {
           contextDir
       },
       dockerGenerateConfig <<=
-        (dockerBaseImage, defaultLinuxInstallLocation, maintainer, daemonUser, normalizedName, dockerExposedPorts, target) map {
-          case (dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, target) =>
-            generateDockerConfig(dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, target)
+        (dockerBaseImage, defaultLinuxInstallLocation, maintainer, daemonUser, normalizedName, dockerExposedPorts, dockerExposedVolumes, target) map {
+          case (dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, exposedVolumes, target) =>
+            generateDockerConfig(dockerBaseImage, baseDirectory, maintainer, daemonUser, normalizedName, exposedPorts, exposedVolumes, target)
         }
     ))
 }

src/main/scala/com/typesafe/sbt/packager/docker/Keys.scala

@@ -11,6 +11,7 @@ trait DockerKeys {
 
   val dockerBaseImage = SettingKey[String]("dockerBaseImage", "Base image for Dockerfile.")
   val dockerExposedPorts = SettingKey[Seq[Int]]("dockerExposedPorts", "Ports exposed by Docker image")
+  val dockerExposedVolumes = SettingKey[Seq[String]]("dockerExposedVolumes", "Volumes exposed by Docker image")
 }
 
 object Keys extends DockerKeys {

src/sbt-test/docker/volumes/build.sbt

@@ -0,0 +1,9 @@
+import NativePackagerKeys._
+
+packagerSettings
+
+name := "simple-test"
+
+version := "0.1.0"
+
+dockerExposedVolumes in Docker := Seq("/opt/docker/logs", "/opt/docker/config")

src/sbt-test/docker/volumes/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % sys.props("project.version"))

src/sbt-test/docker/volumes/test

@@ -0,0 +1,4 @@
+# Stage the distribution and ensure files show up.
+> docker:stage
+$ exec grep -q -F 'VOLUME ["/opt/docker/logs", "/opt/docker/config"]' target/docker/Dockerfile
+$ exec grep -q -F 'RUN ["mkdir", "-p", "/opt/docker/logs", "/opt/docker/config"]' target/docker/Dockerfile