Add support for buildx

README.md

@@ -168,12 +168,22 @@ docker / imageNames := Seq(
 
 Use the key `docker / buildOptions` to set build options.
 
-Example:
+#### cross-platform
+The `platforms` parameter enables the cross-platform build.
+With valuing this parameter the docker image will build using `buildx` command and the host environment should already been set up for.
+
+⚠️ For using the cross builds you need QEMU binaries
+```shell
+docker run --privileged --rm tonistiigi/binfmt --install all
+```
+
+#### Example:
 ```scala
 docker / buildOptions := BuildOptions(
   cache = false,
   removeIntermediateContainers = BuildOptions.Remove.Always,
   pullBaseImage = BuildOptions.Pull.Always,
+  platforms = List("linux/arm64/v8"),
   additionalArguments = Seq("--add-host", "127.0.0.1:12345", "--compress")
 )
 ```

project/build.properties

@@ -1 +1 @@
-sbt.version=1.6.2
+sbt.version=1.8.0

src/main/scala/sbtdocker/DockerBuild.scala

@@ -113,19 +113,23 @@ object DockerBuild {
     var lines = Seq.empty[String]
 
     def runBuild(buildKitSupport: Boolean): Int = {
+      val buildX = if (buildOptions.platforms.isEmpty) Nil else List("buildx")
+      val load = if (buildOptions.platforms.isEmpty) Nil else List("--load")
       val buildOptionFlags = generateBuildOptionFlags(buildOptions)
       val buildKitFlags = if (buildKitSupport) List("--progress=plain") else Nil
       val buildArgumentFlags = buildArguments.toList.flatMap {
         case (key, value) =>
           Seq(s"--build-arg", s"$key=$value")
       }
       val command: Seq[String] = dockerPath ::
+        buildX :::
         "build" ::
         buildOptionFlags :::
         buildKitFlags :::
         buildArgumentFlags :::
+        load :::
         "--file" ::
-        dockerfilePath.name ::
+        dockerfileAbsolutePath.getPath ::
         dockerfileAbsolutePath.getParentFile.getPath ::
         Nil
       log.debug(s"Running command: '${command.mkString(" ")}'")
@@ -187,18 +191,24 @@ object DockerBuild {
       }
       "--pull=" + value
     }
+    val platformsFlag: List[String] = buildOptions.platforms match {
+      case Seq() => Nil
+      case platforms => List(s"--platform=${platforms.mkString(",")}")
+    }
 
-    cacheFlag :: removeFlag :: pullFlag :: buildOptions.additionalArguments.toList
+    cacheFlag :: removeFlag :: pullFlag :: platformsFlag ::: buildOptions.additionalArguments.toList
   }
 
   private val SuccessfullyBuilt = "^Successfully built ([0-9a-f]+)$".r
   private val SuccessfullyBuiltBuildKit = ".* writing image sha256:([0-9a-f]+) .*\\bdone$".r
+  private val SuccessfullyBuiltBuildx = ".* exporting config sha256:([0-9a-f]+) .*\\bdone$".r
   private val SuccessfullyBuiltPodman = "^([0-9a-f]{64})$".r
 
   private[sbtdocker] def parseImageId(lines: Seq[String]): Option[ImageId] = {
     lines.collect {
       case SuccessfullyBuilt(id) => ImageId(id)
       case SuccessfullyBuiltBuildKit(id) => ImageId(id)
+      case SuccessfullyBuiltBuildx(id) => ImageId(id)
       case SuccessfullyBuiltPodman(id) => ImageId(id)
     }.lastOption
   }

src/main/scala/sbtdocker/models.scala

@@ -31,12 +31,14 @@ object BuildOptions {
   * @param cache Use cache when building the image.
   * @param removeIntermediateContainers Remove intermediate containers after a build.
   * @param pullBaseImage Always attempts to pull a newer version of the base image.
+  * @param platforms Allows cross platform builds. Make sure that you already set docker's buildx up on the machine that uses this feature
   * @param additionalArguments Provide any other arguments to the `docker build` task, see reference at https://docs.docker.com/engine/reference/commandline/build/#options. For example `Seq("--add-host", "127.0.0.1:12345", "--compress")`.
   */
 final case class BuildOptions(
   cache: Boolean = true,
   removeIntermediateContainers: BuildOptions.Remove.Option = BuildOptions.Remove.OnSuccess,
   pullBaseImage: BuildOptions.Pull.Option = BuildOptions.Pull.IfMissing,
+  platforms: Seq[String] = Seq.empty,
   additionalArguments: Seq[String] = Seq.empty
 )
 

src/test/scala/sbtdocker/DockerBuildSpec.scala

@@ -98,6 +98,14 @@ class DockerBuildSpec extends AnyFreeSpec with Matchers {
       flags should contain("--pull=true")
     }
 
+    "Add platform argument for cross build" in {
+      val options = BuildOptions(platforms = List("linux/amd64", "linux/arm64"))
+      val flags = DockerBuild.generateBuildOptionFlags(options)
+
+      flags should contain("--platform=linux/amd64,linux/arm64")
+
+    }
+
     "Custom arguments" in {
       val options = BuildOptions(additionalArguments = Seq("--add-host", "127.0.0.1:12345", "--compress"))
       val flags = DockerBuild.generateBuildOptionFlags(options)
@@ -117,6 +125,18 @@ class DockerBuildSpec extends AnyFreeSpec with Matchers {
       DockerBuild.parseImageId(lines) shouldEqual Some(ImageId("353fcb84af6b"))
     }
 
+    "Docker buildx output" in {
+      val lines = Seq(
+        "#7 exporting layers 0.4s done",
+        "#7 exporting manifest sha256:427ff04564194e7d44a5790d5739465789861cb5ee6db60ccdb15388865dfd64 0.0s done",
+        "#7 exporting config sha256:d1d7dbb3987417e91239032f2a36a2ede76e62276849ebf362004c14d6fc82ac",
+        "#7 exporting config sha256:d1d7dbb3987417e91239032f2a36a2ede76e62276849ebf362004c14d6fc82ac 0.0s done",
+        "#7 sending tarball"
+      )
+      DockerBuild.parseImageId(lines) shouldEqual Some(ImageId("d1d7dbb3987417e91239032f2a36a2ede76e62276849ebf362004c14d6fc82ac"))
+
+    }
+
     "Docker build output version 20.10.10" in {
       val lines = Seq(
         "#6 exporting to image",