Read PACK_USER_ID:PACK_USER_GID for daemon export

[#50]

build_test.go

@@ -516,6 +516,38 @@ func testBuild(t *testing.T, when spec.G, it spec.S) {
 					assertEq(t, metadata.Buildpacks[0].Layers["mylayer"].Data, map[string]interface{}{"key": "myval"})
 					assertContains(t, metadata.Buildpacks[0].Layers["other"].SHA, "sha256:")
 				})
+
+				it("sets owner of layer files to PACK_USER_ID:PACK_USER_GID", func() {
+					subject.RunImage = "packs/run-" + randString(8)
+					defer exec.Command("docker", "rmi", subject.RunImage)
+					cmd := exec.Command("docker", "build", "-t", subject.RunImage, "-")
+					cmd.Stdin = strings.NewReader(`
+						FROM packs/run
+						ENV PACK_USER_ID 1234
+						ENV PACK_USER_GID 5678
+					`)
+					assertNil(t, cmd.Run())
+
+					assertNil(t, subject.Export(group))
+					txt, err := exec.Command("docker", "run", subject.RepoName, "ls", "-la", "/workspace/app/file.txt").Output()
+					assertNil(t, err)
+					assertContains(t, string(txt), " 1234 5678 ")
+				})
+
+				it("errors if run image is missing PACK_USER_ID", func() {
+					subject.RunImage = "packs/run-" + randString(8)
+					defer exec.Command("docker", "rmi", subject.RunImage)
+					cmd := exec.Command("docker", "build", "-t", subject.RunImage, "-")
+					cmd.Stdin = strings.NewReader(`
+						FROM packs/run
+						ENV PACK_USER_ID ''
+						ENV PACK_USER_GID 5678
+					`)
+					assertNil(t, cmd.Run())
+
+					err := subject.Export(group)
+					assertError(t, err, "export uid/gid: could not find PACK_USER_ID && PACK_USER_GID from run image")
+				})
 			})
 		})
 

exporter.go

@@ -21,6 +21,8 @@ import (
 	"github.com/buildpack/pack/fs"
 	"github.com/buildpack/pack/image"
 	"github.com/buildpack/packs"
+
+	"github.com/buildpack/packs"
 )
 
 func exportRegistry(group *lifecycle.BuildpackGroup, workspaceDir, repoName, stackName string, stdout, stderr io.Writer) (string, error) {
@@ -73,6 +75,25 @@ func exportRegistry(group *lifecycle.BuildpackGroup, workspaceDir, repoName, sta
 	return sha.String(), nil
 }
 
+func runImageUIDGID(cli Docker, ctx context.Context, runImage string) (string, error) {
+	i, _, err := cli.ImageInspectWithRaw(ctx, runImage)
+	if err != nil {
+		return "", errors.Wrap(err, "inspect image to find UID & GID")
+	}
+	var uid, gid string
+	for _, e := range i.Config.Env {
+		if strings.HasPrefix(e, "PACK_USER_ID=") {
+			uid = e[13:]
+		} else if strings.HasPrefix(e, "PACK_USER_GID=") {
+			gid = e[14:]
+		}
+	}
+	if uid == "" || gid == "" {
+		return "", errors.New("could not find PACK_USER_ID && PACK_USER_GID from run image")
+	}
+	return uid + ":" + gid, nil
+}
+
 func exportDaemon(cli Docker, buildpacks []string, workspaceVolume, repoName, runImage string, stdout io.Writer) error {
 	ctx := context.Background()
 	ctr, err := cli.ContainerCreate(ctx, &container.Config{
@@ -94,7 +115,12 @@ func exportDaemon(cli Docker, buildpacks []string, workspaceVolume, repoName, ru
 		return errors.Wrap(err, "copy from container")
 	}
 
-	r2, layerChan, errChan := addDockerfileToTar(runImage, repoName, buildpacks, r)
+	chownUser, err := runImageUIDGID(cli, ctx, runImage)
+	if err != nil {
+		return errors.Wrap(err, "export uid/gid")
+	}
+
+	r2, layerChan, errChan := addDockerfileToTar(chownUser, runImage, repoName, buildpacks, r)
 
 	res, err := cli.ImageBuild(ctx, r2, dockertypes.ImageBuildOptions{Tags: []string{repoName}})
 	if err != nil {
@@ -183,10 +209,10 @@ type dockerfileLayer struct {
 	data      interface{}
 }
 
-func addDockerfileToTar(runImage, repoName string, buildpacks []string, r io.Reader) (io.Reader, chan []dockerfileLayer, chan error) {
+func addDockerfileToTar(chownUser, runImage, repoName string, buildpacks []string, r io.Reader) (io.Reader, chan []dockerfileLayer, chan error) {
 	dockerFile := "FROM " + runImage + "\n"
-	dockerFile += "ADD --chown=pack:pack /workspace/app /workspace/app\n"
-	dockerFile += "ADD --chown=pack:pack /workspace/config /workspace/config\n"
+	dockerFile += fmt.Sprintf("ADD --chown=%s /workspace/app /workspace/app\n", chownUser)
+	dockerFile += fmt.Sprintf("ADD --chown=%s /workspace/config /workspace/config\n", chownUser)
 	layerChan := make(chan []dockerfileLayer, 1)
 	var layerNames []dockerfileLayer
 	errChan := make(chan error, 1)
@@ -263,9 +289,9 @@ func addDockerfileToTar(runImage, repoName string, buildpacks []string, r io.Rea
 			for _, layer := range layers {
 				layerNames = append(layerNames, dockerfileLayer{buildpack, layer, tomlFiles[buildpack][layer]})
 				if dirs[buildpack][layer] {
-					dockerFile += fmt.Sprintf("ADD --chown=pack:pack /workspace/%s/%s /workspace/%s/%s\n", buildpack, layer, buildpack, layer)
+					dockerFile += fmt.Sprintf("ADD --chown=%s /workspace/%s/%s /workspace/%s/%s\n", chownUser, buildpack, layer, buildpack, layer)
 				} else {
-					dockerFile += fmt.Sprintf("COPY --from=prev --chown=pack:pack /workspace/%s/%s /workspace/%s/%s\n", buildpack, layer, buildpack, layer)
+					dockerFile += fmt.Sprintf("COPY --from=prev --chown=%s /workspace/%s/%s /workspace/%s/%s\n", chownUser, buildpack, layer, buildpack, layer)
 					copyFromPrev = true
 				}
 			}