Merge pull request #117 from olofwalker/return-image-id-from-docker-push

Return image name and id from dockerPush and dockerBuildAndPush

src/main/scala/sbtdocker/DockerKeys.scala

@@ -4,8 +4,8 @@ import sbt._
 
 object DockerKeys {
   val docker = taskKey[ImageId]("Build a Docker image.")
-  val dockerBuildAndPush = taskKey[ImageId]("Build a Docker image and pushes it to a registry.")
-  val dockerPush = taskKey[Unit]("Push a already built Docker image to a registry.")
+  val dockerBuildAndPush = taskKey[Map[ImageName, ImageDigest]]("Build a Docker image and pushes it to a registry.")
+  val dockerPush = taskKey[Map[ImageName, ImageDigest]]("Push a already built Docker image to a registry.")
 
   @deprecated("Use imageNames instead.", "1.0.0")
   val imageName = taskKey[ImageName]("Name of the built image.")

src/main/scala/sbtdocker/DockerPush.scala

@@ -13,10 +13,10 @@ object DockerPush {
     * @param imageNames names of the images to push
     * @param log logger
     */
-  def apply(dockerPath: String, imageNames: Seq[ImageName], log: Logger): Unit = {
-    imageNames.foreach { imageName =>
+  def apply(dockerPath: String, imageNames: Seq[ImageName], log: Logger): Map[ImageName, ImageDigest] = {
+    imageNames.map { imageName =>
       apply(dockerPath, imageName, log)
-    }
+    }.toMap
   }
 
   /**
@@ -26,15 +26,18 @@ object DockerPush {
     * @param imageName name of the image to push
     * @param log logger
     */
-  def apply(dockerPath: String, imageName: ImageName, log: Logger): Unit = {
+  def apply(dockerPath: String, imageName: ImageName, log: Logger): (ImageName, ImageDigest) = {
     log.info(s"Pushing docker image with name: '$imageName'")
 
+    var lines = Seq.empty[String]
     val processLog = ProcessLogger(
       { line =>
         log.info(line)
+        lines :+= line
       },
       { line =>
         log.info(line)
+        lines :+= line
       }
     )
 
@@ -44,5 +47,20 @@ object DockerPush {
     val process = Process(command)
     val exitValue = process ! processLog
     if (exitValue != 0) sys.error("Failed to push")
+
+    val PushedImageDigestSha256 = ".* digest: sha256:([0-9a-f]+) .*".r
+
+    val imageDigest = lines.collect {
+      case PushedImageDigestSha256(digest) => ImageDigest("sha256", digest)
+    }.lastOption
+
+    imageDigest match {
+      case Some(digest) =>
+        imageName -> digest
+      case None =>
+        throw new DockerPushException("Could not parse Docker image digest")
+    }
   }
 }
+
+class DockerPushException(message: String) extends RuntimeException(message)

src/main/scala/sbtdocker/DockerSettings.scala

@@ -26,10 +26,9 @@ object DockerSettings {
       DockerPush(dockerPath, imageNames, log)
     },
     dockerBuildAndPush := Def.taskDyn {
-      val id = docker.value
+      docker.value
       Def.task {
         dockerPush.value
-        id
       }
     }.value,
     dockerfile in docker := {

src/main/scala/sbtdocker/models.scala

@@ -32,7 +32,7 @@ object BuildOptions {
   * @param removeIntermediateContainers Remove intermediate containers after a build.
   * @param pullBaseImage Always attempts to pull a newer version of the base image.
   */
-case class BuildOptions(
+final case class BuildOptions(
   cache: Boolean = true,
   removeIntermediateContainers: BuildOptions.Remove.Option = BuildOptions.Remove.OnSuccess,
   pullBaseImage: BuildOptions.Pull.Option = BuildOptions.Pull.IfMissing
@@ -42,10 +42,19 @@ case class BuildOptions(
   * Id of an Docker image.
   * @param id Id as a hexadecimal digit string.
   */
-case class ImageId(id: String) {
+final case class ImageId(id: String) extends AnyVal {
   override def toString = id
 }
 
+/**
+  * The image digest, the format of the digest is `algorithm:hex-string`
+  * @param algorithm The algorithm used to produce the digest.
+  * @param digest A digest of the image, as a string.
+  */
+final case class ImageDigest(algorithm: String, digest: String) {
+  override def toString = s"$algorithm:$digest"
+}
+
 object ImageName {
 
   /**
@@ -88,7 +97,7 @@ object ImageName {
   * @param namespace Namespace name.
   * @param tag Tag, for example a version number.
   */
-case class ImageName(
+final case class ImageName(
   registry: Option[String] = None,
   namespace: Option[String] = None,
   repository: String,