Reorganized vacation package

- introduces vacation.NopArchive type for non-archive files
- splits vacation implementation files up into type-named files
- renames vacation test files to remove stutter
- adds vacation.Archive.WithName option to allow NopArchives to have
  specified names
- uses vacation.Archive.WithName option in postal.Service.Deliver to
  deliver file to location matching the dependency URI basename
- includes application/jar mime-type as NopArchive type

Author: Ryan Moran

postal/service.go

@@ -156,7 +156,8 @@ func (s Service) Deliver(dependency Dependency, cnbPath, layerPath, platformPath
 
 	validatedReader := cargo.NewValidatedReader(bundle, dependency.SHA256)
 
-	err = vacation.NewArchive(validatedReader).StripComponents(dependency.StripComponents).Decompress(layerPath)
+	name := filepath.Base(dependency.URI)
+	err = vacation.NewArchive(validatedReader).WithName(name).StripComponents(dependency.StripComponents).Decompress(layerPath)
 	if err != nil {
 		return err
 	}

postal/service_test.go

@@ -404,6 +404,7 @@ version = "this is super not semver"
 			Expect(err).NotTo(HaveOccurred())
 			Expect(info.Mode()).To(Equal(os.FileMode(0755)))
 		})
+
 		context("when the dependency has a strip-components value set", func() {
 			it.Before(func() {
 				var err error
@@ -484,7 +485,55 @@ version = "this is super not semver"
 				Expect(err).NotTo(HaveOccurred())
 				Expect(info.Mode()).To(Equal(os.FileMode(0755)))
 			})
+		})
+
+		context("when the dependency should be a named file", func() {
+			it.Before(func() {
+				var err error
+				layerPath, err = os.MkdirTemp("", "path")
+				Expect(err).NotTo(HaveOccurred())
+
+				buffer := bytes.NewBuffer(nil)
+				buffer.WriteString("some-file-contents")
+
+				sum := sha256.Sum256(buffer.Bytes())
+				dependencySHA = hex.EncodeToString(sum[:])
+
+				transport.DropCall.Returns.ReadCloser = io.NopCloser(buffer)
+
+				deliver = func() error {
+					return service.Deliver(postal.Dependency{
+						ID:      "some-entry",
+						Stacks:  []string{"some-stack"},
+						URI:     "https://dependencies.example.com/dependencies/some-file-name.txt",
+						SHA256:  dependencySHA,
+						Version: "1.2.3",
+					}, "some-cnb-path",
+						layerPath,
+						platformPath,
+					)
+				}
+			})
+
+			it.After(func() {
+				Expect(os.RemoveAll(layerPath)).To(Succeed())
+			})
 
+			it("downloads the dependency and copies it into the path with the given name", func() {
+				err := deliver()
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(transport.DropCall.Receives.Root).To(Equal("some-cnb-path"))
+				Expect(transport.DropCall.Receives.Uri).To(Equal("https://dependencies.example.com/dependencies/some-file-name.txt"))
+
+				files, err := filepath.Glob(fmt.Sprintf("%s/*", layerPath))
+				Expect(err).NotTo(HaveOccurred())
+				Expect(files).To(ConsistOf([]string{filepath.Join(layerPath, "some-file-name.txt")}))
+
+				content, err := os.ReadFile(filepath.Join(layerPath, "some-file-name.txt"))
+				Expect(err).NotTo(HaveOccurred())
+				Expect(string(content)).To(Equal("some-file-contents"))
+			})
 		})
 
 		context("when there is a dependency mapping via binding", func() {

vacation/archive.go

@@ -0,0 +1,89 @@
+package vacation
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/gabriel-vasile/mimetype"
+)
+
+type Decompressor interface {
+	Decompress(destination string) error
+}
+
+// An Archive decompresses tar, gzip, xz, and bzip2 compressed tar, and zip files from
+// an input stream.
+type Archive struct {
+	reader     io.Reader
+	components int
+	name       string
+}
+
+// NewArchive returns a new Archive that reads from inputReader.
+func NewArchive(inputReader io.Reader) Archive {
+	return Archive{
+		reader: inputReader,
+		name:   "artifact",
+	}
+}
+
+// Decompress reads from Archive, determines the archive type of the input
+// stream, and writes files into the destination specified.
+//
+// Archive decompression will also handle files that are types "text/plain;
+// charset=utf-8" and write the contents of the input stream to a file name
+// "artifact" in the destination directory.
+func (a Archive) Decompress(destination string) error {
+	// Convert reader into a buffered read so that the header can be peeked to
+	// determine the type.
+	bufferedReader := bufio.NewReader(a.reader)
+
+	// The number 3072 is lifted from the mimetype library and the definition of
+	// the constant at the time of writing this functionality is listed below.
+	// https://github.com/gabriel-vasile/mimetype/blob/c64c025a7c2d8d45ba57d3cebb50a1dbedb3ed7e/internal/matchers/matchers.go#L6
+	header, err := bufferedReader.Peek(3072)
+	if err != nil && err != io.EOF {
+		return err
+	}
+
+	mime := mimetype.Detect(header)
+
+	// This switch case is reponsible for determining what the decompression
+	// strategy should be.
+	var decompressor Decompressor
+	switch mime.String() {
+	case "application/x-tar":
+		decompressor = NewTarArchive(bufferedReader).StripComponents(a.components)
+	case "application/gzip":
+		decompressor = NewTarGzipArchive(bufferedReader).StripComponents(a.components)
+	case "application/x-xz":
+		decompressor = NewTarXZArchive(bufferedReader).StripComponents(a.components)
+	case "application/x-bzip2":
+		decompressor = NewTarBzip2Archive(bufferedReader).StripComponents(a.components)
+	case "application/zip":
+		decompressor = NewZipArchive(bufferedReader)
+	case "text/plain; charset=utf-8", "application/jar":
+		destination = filepath.Join(destination, a.name)
+		decompressor = NewNopArchive(bufferedReader)
+	default:
+		return fmt.Errorf("unsupported archive type: %s", mime.String())
+	}
+
+	return decompressor.Decompress(destination)
+}
+
+// StripComponents behaves like the --strip-components flag on tar command
+// removing the first n levels from the final decompression destination.
+// Setting this is a no-op for archive types that do not use --strip-components
+// (such as zip).
+func (a Archive) StripComponents(components int) Archive {
+	a.components = components
+	return a
+}
+
+func (a Archive) WithName(name string) Archive {
+	a.name = name
+	return a
+}

vacation/vacation_archive_test.go vacation/archive_test.go

@@ -17,7 +17,7 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-func testVacationArchive(t *testing.T, context spec.G, it spec.S) {
+func testArchive(t *testing.T, context spec.G, it spec.S) {
 	var (
 		Expect = NewWithT(t).Expect
 	)
@@ -322,6 +322,99 @@ func testVacationArchive(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 
+		context("when passed the reader of a text file", func() {
+			var (
+				archive vacation.Archive
+				tempDir string
+			)
+
+			it.Before(func() {
+				var err error
+				tempDir, err = os.MkdirTemp("", "vacation")
+				Expect(err).NotTo(HaveOccurred())
+
+				buffer := bytes.NewBuffer([]byte(`some contents`))
+
+				archive = vacation.NewArchive(buffer)
+			})
+
+			it.After(func() {
+				Expect(os.RemoveAll(tempDir)).To(Succeed())
+			})
+
+			it("writes a text file onto the path", func() {
+				err := archive.Decompress(tempDir)
+				Expect(err).NotTo(HaveOccurred())
+
+				content, err := os.ReadFile(filepath.Join(tempDir, "artifact"))
+				Expect(err).NotTo(HaveOccurred())
+				Expect(content).To(Equal([]byte(`some contents`)))
+			})
+
+			context("when given a name", func() {
+				it.Before(func() {
+					archive = archive.WithName("some-text-file")
+				})
+
+				it("writes a text file onto the path with that name", func() {
+					err := archive.Decompress(tempDir)
+					Expect(err).NotTo(HaveOccurred())
+
+					content, err := os.ReadFile(filepath.Join(tempDir, "some-text-file"))
+					Expect(err).NotTo(HaveOccurred())
+					Expect(content).To(Equal([]byte(`some contents`)))
+				})
+			})
+		})
+
+		context("when passed the reader of a jar file", func() {
+			var (
+				archive vacation.Archive
+				tempDir string
+				header  []byte
+			)
+
+			it.Before(func() {
+				var err error
+				tempDir, err = os.MkdirTemp("", "vacation")
+				Expect(err).NotTo(HaveOccurred())
+
+				// JAR header copied from https://github.com/gabriel-vasile/mimetype/blob/c4c6791c993e7f509de8ef38f149a59533e30bbc/testdata/jar.jar
+				header = []byte("\x50\x4b\x03\x04\x14\x00\x08\x08\x08\x00\x59\x71\xbf\x4c\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x09\x00\x04\x00\x4d\x45\x54\x41\x2d\x49\x4e\x46\x2f\xfe\xca\x00\x00\x03\x00\x50\x4b\x07\x08\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x50\x4b\x03\x04\x14\x00\x08\x08\x08\x00\x59\x71\xbf\x4c\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x4d\x45\x54\x41\x2d\x49\x4e\x46\x2f\x4d\x41\x4e\x49\x46\x45\x53\x54\x2e\x4d\x46\xf3\x4d\xcc\xcb\x4c\x4b\x2d\x2e\xd1\x0d\x4b\x2d\x2a\xce\xcc\xcf\xb3\x52\x30\xd4\x33\xe0\xe5\x72\x2e\x4a\x4d\x2c\x49\x4d\xd1\x75\xaa\x04\x09\x58\xe8\x19\xc4\x1b\x9a\x1a\x2a\x68\xf8\x17\x25\x26\xe7\xa4\x2a\x38\xe7\x17\x15\xe4\x17\x25\x96\x00\xd5\x6b\xf2\x72\xf9\x26\x66\xe6\xe9\x3a\xe7\x24\x16\x17\x5b\x29\x78\xa4\xe6\xe4\xe4\x87\xe7\x17\xe5\xa4\xf0\x72\xf1\x72\x01\x00\x50\x4b\x07\x08\x86\x7d\x5d\xeb\x5c\x00\x00\x00\x5d\x00\x00\x00\x50\x4b\x03\x04\x14\x00\x08\x08\x08\x00\x12\x71\xbf\x4c\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x48\x65\x6c\x6c\x6f\x57\x6f\x72\x6c\x64\x2e\x63\x6c\x61\x73\x73\x6d\x50\x4d\x4b\xc3\x40\x10\x7d\xdb\xa6\x4d\x13\x53\x53\x5b\x53\x3f\x0b\xf6\x50\x88\x22\xe6\xe2\xad\xe2\x45\x10\x0f\x45\x85\x88\x1e\x3c\x6d\xda\xa5\x6c\xd9\x24\x12\x13\xc1\x9f\xa5\x07\x05\x0f\xfe\x00\x7f\x94\x38\x1b\x85\x20\x74\x0f\xb3\x3b\x6f\xde\x9b\x79\xb3\x5f\xdf\x1f\x9f\x00\x8e\x31\xb0\xd1\x84\x6b\xa1\x83\xb5\x16\xba\x36\x7a\x58\x37\xe1\x99\xe8\x33\x34\x4f\x64\x22\xf3\x53\x86\xba\xbf\x7f\xcb\x60\x9c\xa5\x33\xc1\xe0\x4e\x64\x22\x2e\x8b\x38\x12\xd9\x0d\x8f\x14\x21\x46\xcc\x65\xc2\xd0\xf7\xef\x27\x0b\xfe\xc4\x03\xc5\x93\x79\x10\xe6\x99\x4c\xe6\x63\x2d\xb4\xc3\xb4\xc8\xa6\xe2\x5c\x6a\xb2\x7b\x21\x94\x4a\xef\xd2\x4c\xcd\x8e\x34\xdb\x81\x89\x96\x89\x0d\x07\x9b\xd8\x62\x68\x97\xe5\xc3\xbd\x92\x30\x34\xb1\xed\x60\x07\xbb\xd4\xa3\x92\x31\x74\xaa\x31\x57\xd1\x42\x4c\xf3\x7f\x50\xf8\xfc\x98\x8b\x98\x5c\xa7\x05\x15\xbc\x5f\x4f\x32\x0d\xae\xc9\x50\x4e\xb6\x04\x8f\xc7\x0c\xbd\x25\x30\x83\xf9\xa0\x33\x45\xdb\x78\xfe\xb2\x65\x30\x44\x83\xfe\x4b\x9f\x1a\x98\xb6\x4e\xd1\xa2\x6c\x40\x37\xa3\xbb\x71\xf0\x0e\xf6\x42\x0f\xb2\x4c\xb1\x59\x82\x9a\xb2\x02\xe7\x8f\x3a\x2a\xa5\x80\xf5\x8a\x5a\xb7\xfe\x06\xa3\xa2\xdb\x54\xa2\x1e\xd4\x55\x0b\xdb\xe5\x94\xd5\x1f\x50\x4b\x07\x08\xe5\x38\x99\x3f\x21\x01\x00\x00\xab\x01\x00\x00\x50\x4b\x01\x02\x14\x00\x14\x00\x08\x08\x08\x00\x59\x71\xbf\x4c\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x09\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x4d\x45\x54\x41\x2d\x49\x4e\x46\x2f\xfe\xca\x00\x00\x50\x4b\x01\x02\x14\x00\x14\x00\x08\x08\x08\x00\x59\x71\xbf\x4c\x86\x7d\x5d\xeb\x5c\x00\x00\x00\x5d\x00\x00\x00\x14\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x3d\x00\x00\x00\x4d\x45\x54\x41\x2d\x49\x4e\x46\x2f\x4d\x41\x4e\x49\x46\x45\x53\x54\x2e\x4d\x46\x50\x4b\x01\x02\x14\x00\x14\x00\x08\x08\x08\x00\x12\x71\xbf\x4c\xe5\x38\x99\x3f\x21\x01\x00\x00\xab\x01\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xdb\x00\x00\x00\x48\x65\x6c\x6c\x6f\x57\x6f\x72\x6c\x64\x2e\x63\x6c\x61\x73\x73\x50\x4b\x05\x06\x00\x00\x00\x00\x03\x00\x03\x00\xbb\x00\x00\x00\x3a\x02\x00\x00\x00\x00")
+				buffer := bytes.NewBuffer(header)
+
+				archive = vacation.NewArchive(buffer)
+			})
+
+			it.After(func() {
+				Expect(os.RemoveAll(tempDir)).To(Succeed())
+			})
+
+			it("writes a jar file onto the path", func() {
+				err := archive.Decompress(tempDir)
+				Expect(err).NotTo(HaveOccurred())
+
+				content, err := os.ReadFile(filepath.Join(tempDir, "artifact"))
+				Expect(err).NotTo(HaveOccurred())
+				Expect(content).To(Equal(header))
+			})
+
+			context("when given a name", func() {
+				it.Before(func() {
+					archive = archive.WithName("some-jar-file")
+				})
+
+				it("writes a jar file onto the path with that name", func() {
+					err := archive.Decompress(tempDir)
+					Expect(err).NotTo(HaveOccurred())
+
+					content, err := os.ReadFile(filepath.Join(tempDir, "some-jar-file"))
+					Expect(err).NotTo(HaveOccurred())
+					Expect(content).To(Equal(header))
+				})
+			})
+		})
+
 		context("failure cases", func() {
 			context("the buffer passed is of are unknown type", func() {
 				var (

vacation/init_test.go

@@ -9,13 +9,13 @@ import (
 
 func TestVacation(t *testing.T) {
 	suite := spec.New("vacation", spec.Report(report.Terminal{}))
-	suite("VacationArchive", testVacationArchive)
-	suite("VacationTarBzip2", testVacationTarBzip2)
-	suite("VacationSymlinkSorting", testVacationSymlinkSorting)
-	suite("VacationTar", testVacationTar)
-	suite("VacationTarGzip", testVacationTarGzip)
-	suite("VacationTarXZ", testVacationTarXZ)
-	suite("VacationText", testVacationText)
-	suite("VacationZip", testVacationZip)
+	suite("Archive", testArchive)
+	suite("NopArchive", testNopArchive)
+	suite("SymlinkSorting", testSymlinkSorting)
+	suite("TarArchive", testTarArchive)
+	suite("TarBzip2Archive", testTarBzip2Archive)
+	suite("TarGzipArchive", testTarGzipArchive)
+	suite("TarXZArchive", testTarXZArchive)
+	suite("ZipArchive", testZipArchive)
 	suite.Run(t)
 }

vacation/nop_archive.go

@@ -0,0 +1,33 @@
+package vacation
+
+import (
+	"io"
+	"os"
+)
+
+// A NopArchive implements the common archive interface, but acts as a no-op,
+// simply copying the reader to the destination.
+type NopArchive struct {
+	reader io.Reader
+}
+
+// NewNopArchive returns a new NopArchive
+func NewNopArchive(r io.Reader) NopArchive {
+	return NopArchive{reader: r}
+}
+
+// Decompress copies the reader contents into the destination specified.
+func (na NopArchive) Decompress(destination string) error {
+	file, err := os.Create(destination)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	_, err = io.Copy(file, na.reader)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

vacation/nop_archive_test.go

@@ -0,0 +1,56 @@
+package vacation_test
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/paketo-buildpacks/packit/vacation"
+	"github.com/sclevine/spec"
+
+	. "github.com/onsi/gomega"
+)
+
+func testNopArchive(t *testing.T, context spec.G, it spec.S) {
+	var Expect = NewWithT(t).Expect
+
+	context("Decompress", func() {
+		var (
+			archive vacation.NopArchive
+			tempDir string
+		)
+
+		it.Before(func() {
+			var err error
+			tempDir, err = os.MkdirTemp("", "vacation")
+			Expect(err).NotTo(HaveOccurred())
+
+			buffer := bytes.NewBuffer([]byte(`some contents`))
+
+			archive = vacation.NewNopArchive(buffer)
+		})
+
+		it.After(func() {
+			Expect(os.RemoveAll(tempDir)).To(Succeed())
+		})
+
+		it("copies the contents of the reader to the destination", func() {
+			err := archive.Decompress(filepath.Join(tempDir, "some-file"))
+			Expect(err).NotTo(HaveOccurred())
+
+			content, err := os.ReadFile(filepath.Join(tempDir, "some-file"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(content).To(Equal([]byte(`some contents`)))
+		})
+
+		context("failure cases", func() {
+			context("when the destination file cannot be created", func() {
+				it("returns an error", func() {
+					err := archive.Decompress("/no/such/path")
+					Expect(err).To(MatchError(ContainSubstring("no such file or directory")))
+				})
+			})
+		})
+	})
+}

vacation/vacation_symlink_sorting_test.go vacation/symlink_sorting_test.go

@@ -15,7 +15,7 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-func testVacationSymlinkSorting(t *testing.T, context spec.G, it spec.S) {
+func testSymlinkSorting(t *testing.T, context spec.G, it spec.S) {
 	var (
 		Expect = NewWithT(t).Expect
 	)