Optimize Docker image layering #1677

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1. muuki88

   added

   docker

   feature request

   on Feb 3, 2025
2. muuki88 commented on Feb 3, 2025

   

   muuki88

   on Feb 3, 2025

   Contributor

   More actions

   Hi @dwickern

   That's indeed very wasteful. I remember vaguely that this was solved at one point, but apparently not 😢

   I assume this can be fixed by re-ordering the dockerCommands ?
   

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

   Lines 188 to 271 in 03f8a0e

   	dockerCommands := {
   	val conv0 = fileConverter.value
   	implicit val conv: FileConverter = conv0
   	val strategy = dockerPermissionStrategy.value
   	val dockerBaseDirectory = (Docker / defaultLinuxInstallLocation).value
   	val user = (Docker / daemonUser).value
   	val uidOpt = (Docker / daemonUserUid).value
   	val group = (Docker / daemonGroup).value
   	val gidOpt = (Docker / daemonGroupGid).value
   	val base = dockerBaseImage.value
   	val addPerms = dockerAdditionalPermissions.value
   	val multiStageId = UUID.randomUUID().toString
   	val generalCommands = makeFromAs(base, "mainstage") +: makeMaintainer((Docker / maintainer).value).toSeq
   	val stage0name = "stage0"
   	val layerMappings = (Docker / dockerLayerMappings).value
   	val layerIdsAscending = layerMappings.map(_.layerId).distinct.sortWith { (a, b) =>
   	// Make the None (unspecified) layer the last layer
   	a.getOrElse(Int.MaxValue) < b.getOrElse(Int.MaxValue)
   	}
   	val stage0: Seq[CmdLike] = strategy match {
   	case DockerPermissionStrategy.MultiStage =>
   	Seq(
   	makeFromAs(base, stage0name),
   	makeLabel("snp-multi-stage" -> "intermediate"),
   	makeLabel("snp-multi-stage-id" -> multiStageId),
   	makeWorkdir(dockerBaseDirectory)
   	) ++
   	layerIdsAscending.map(l => makeCopyLayerIntermediate(l, dockerBaseDirectory)) ++
   	Seq(makeUser("root")) ++ layerIdsAscending.map(l =>
   	makeChmodRecursive(dockerChmodType.value, Seq(pathInLayer(dockerBaseDirectory, l)))
   	) ++ {
   	val layerToPath = (Docker / dockerGroupLayers).value
   	addPerms map { case (tpe, v) =>
   	// Try and find the source file for the path from the mappings
   	val layerId = layerMappings
   	.find(_.path == v)
   	.map(_.layerId)
   	.getOrElse {
   	// We couldn't find a source file for the mapping, so try with a dummy source file,
   	// in case there is an explicitly configured path based layer mapping, eg for a directory.
   	layerToPath.lift((PluginCompat.toFileRef(new File("/dev/null")), v))
   	}
   	makeChmod(tpe, Seq(pathInLayer(v, layerId)))
   	}
   	} ++
   	Seq(DockerStageBreak)
   	case _ => Seq()
   	}
   	val stage1: Seq[CmdLike] = generalCommands ++
   	(uidOpt match {
   	case Some(_) => Seq(makeUser("root"), makeUserAdd(user, group, uidOpt, gidOpt))
   	case _ => Seq()
   	}) ++
   	Seq(makeWorkdir(dockerBaseDirectory)) ++ {
   	(strategy match {
   	case DockerPermissionStrategy.MultiStage =>
   	layerIdsAscending.map { layerId =>
   	makeCopyFrom(pathInLayer(dockerBaseDirectory, layerId), dockerBaseDirectory, stage0name, user, group)
   	}
   	case DockerPermissionStrategy.Run =>
   	layerIdsAscending.map(layerId => makeCopyLayerDirect(layerId, dockerBaseDirectory)) ++
   	Seq(makeChmodRecursive(dockerChmodType.value, Seq(dockerBaseDirectory))) ++
   	(addPerms map { case (tpe, v) => makeChmod(tpe, Seq(v)) })
   	case DockerPermissionStrategy.CopyChown =>
   	layerIdsAscending.map(layerId => makeCopyChown(layerId, dockerBaseDirectory, user, group))
   	case DockerPermissionStrategy.None =>
   	layerIdsAscending.map(layerId => makeCopyLayerDirect(layerId, dockerBaseDirectory))
   	})
   	} ++
   	dockerLabels.value.map(makeLabel) ++
   	dockerEnvVars.value.map(makeEnvVar) ++
   	makeExposePorts(dockerExposedPorts.value, dockerExposedUdpPorts.value) ++
   	makeVolumes(dockerExposedVolumes.value, user, group) ++
   	Seq(uidOpt match {
   	case Some(uid) => makeUser(uid, gidOpt)
   	case _ => makeUser(user)
   	}) ++
   	// Use this to debug permissions
   	// Seq(ExecCmd("RUN", Seq("ls", "-l", "/opt/docker/bin/"): _*)) ++
   	Seq(makeEntrypoint(dockerEntrypoint.value), makeCmd(dockerCmd.value))
   	stage0 ++ stage1
   	}
3. dwickern commented on Feb 4, 2025

   

   dwickern

   on Feb 4, 2025

   CollaboratorAuthor

   More actions

   It's actually dockerGroupLayers. it will be easy to fix... more work to update the tests 😅
   

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

   Lines 108 to 140 in 03f8a0e

   	dockerGroupLayers := {
   	val conv0 = fileConverter.value
   	implicit val conv: FileConverter = conv0
   	val dockerBaseDirectory = (Docker / defaultLinuxInstallLocation).value
   	// Ensure this doesn't break even if the JvmPlugin isn't enabled.
   	var artifacts = projectDependencyArtifacts.?.value.getOrElse(Nil).map(_.data).toSet
   	// add the classpath jar to the project artifacts to improve layer caching as it is created by
   	// the ClasspathJarPlugin and is not part of the projectDependencyArtifacts
   	ClasspathJarPlugin.autoImport.packageJavaClasspathJar.?.value match {
   	case Some(p) => artifacts += p
   	case _ =>
   	}
   	val oldFunction = dockerLayerGrouping.value
   	// By default we set this to a function that always returns None.
   	val oldPartialFunction = Function.unlift((tuple: (PluginCompat.FileRef, String)) => oldFunction(tuple._2))
   	val libDir = dockerBaseDirectory + "/lib/"
   	val binDir = dockerBaseDirectory + "/bin/"
   	val jreDir = dockerBaseDirectory + "/jre/"
   	val confDir = dockerBaseDirectory + "/conf/"
   	oldPartialFunction.orElse {
   	// bin directory contains start scripts which are containing artifacts / classpath jar,
   	// so should be together with actual artifacts
   	case (file, path) if artifacts(file) || path.startsWith(binDir) => 4
   	case (_, path) if path.startsWith(jreDir) => 3
   	case (_, path) if path.startsWith(libDir) => 2
   	case (_, path) if path.startsWith(confDir) => 1
   	}
   	},

   #1425 made some improvements before. The layering is pretty good for most applications. The issue is Play Framework outputs additional jars besides the default packageBin

   👍React with 👍1Reacted by Muki Seiler