From 999a53ca76366a1ed221f7be9fe512b7b3a79f1f Mon Sep 17 00:00:00 2001
From: Chris Lundquist <rampantdurandal@gmail.com>
Date: Tue, 24 Jul 2018 19:46:21 +0000
Subject: [PATCH] add support for xz compression #6523

---
 post-processor/compress/benchmark.go      | 32 +++++++++++++++++++++++
 post-processor/compress/post-processor.go | 15 +++++++++++
 2 files changed, 47 insertions(+)

diff --git a/post-processor/compress/benchmark.go b/post-processor/compress/benchmark.go
index ed4d68168..3b97ad342 100644
--- a/post-processor/compress/benchmark.go
+++ b/post-processor/compress/benchmark.go
@@ -105,6 +105,16 @@ func main() {
 	c.Close()
 	fmt.Printf("lz4:\twriter %s\treader %s\tsize %d\n", resw.T.String(), resr.T.String(), c.sw)
 
+	c, err = NewCompressor("/tmp/image.r", "/tmp/image.w")
+	if err != nil {
+		panic(err)
+	}
+	resw = testing.Benchmark(c.BenchmarkXZWriter)
+	c.w.Seek(0, 0)
+	resr = testing.Benchmark(c.BenchmarkXZReader)
+	c.Close()
+	fmt.Printf("xz:\twriter %s\treader %s\tsize %d\n", resw.T.String(), resr.T.String(), c.sw)
+
 }
 
 func (c *Compressor) BenchmarkGZIPWriter(b *testing.B) {
@@ -195,3 +205,25 @@ func (c *Compressor) BenchmarkLZ4Reader(b *testing.B) {
 		b.Fatal(err)
 	}
 }
+
+func (c *Compressor) BenchmarkXZWriter(b *testing.B) {
+	cw := xz.NewWriter(c.w)
+	b.ResetTimer()
+
+	_, err := io.Copy(cw, c.r)
+	if err != nil {
+		b.Fatal(err)
+	}
+	cw.Close()
+	c.w.Sync()
+}
+
+func (c *Compressor) BenchmarkXZReader(b *testing.B) {
+	cr := xz.NewReader(c.w)
+	b.ResetTimer()
+
+	_, err := io.Copy(ioutil.Discard, cr)
+	if err != nil {
+		b.Fatal(err)
+	}
+}
diff --git a/post-processor/compress/post-processor.go b/post-processor/compress/post-processor.go
index 3e089f867..eee13eb22 100644
--- a/post-processor/compress/post-processor.go
+++ b/post-processor/compress/post-processor.go
@@ -18,6 +18,7 @@ import (
 	"github.com/hashicorp/packer/template/interpolate"
 	"github.com/klauspost/pgzip"
 	"github.com/pierrec/lz4"
+	"github.com/ulikunitz/xz"
 )
 
 var (
@@ -142,6 +143,11 @@ func (p *PostProcessor) PostProcess(ui packer.Ui, artifact packer.Artifact) (pac
 			runtime.GOMAXPROCS(-1), target))
 		output, err = makeLZ4Writer(outputFile, p.config.CompressionLevel)
 		defer output.Close()
+	case "xz":
+		ui.Say(fmt.Sprintf("Using xz compression with %d cores for %s",
+			runtime.GOMAXPROCS(-1), target))
+		output, err = makeXZWriter(outputFile, p.config.CompressionLevel)
+		defer output.Close()
 	case "pgzip":
 		ui.Say(fmt.Sprintf("Using pgzip compression with %d cores for %s",
 			runtime.GOMAXPROCS(-1), target))
@@ -209,6 +215,7 @@ func (config *Config) detectFromFilename() {
 		"gz":   "pgzip",
 		"lz4":  "lz4",
 		"bgzf": "bgzf",
+		"xz":   "xz",
 	}
 
 	if config.Format == "" {
@@ -273,6 +280,14 @@ func makeLZ4Writer(output io.WriteCloser, compressionLevel int) (io.WriteCloser,
 	return lzwriter, nil
 }
 
+func makeXZWriter(output io.WriteCloser, compressionLevel int) (io.WriteCloser, error) {
+	xzwriter, err := xz.NewWriter(output)
+	if err != nil {
+		return nil, err
+	}
+	return xzwriter, nil
+}
+
 func makePgzipWriter(output io.WriteCloser, compressionLevel int) (io.WriteCloser, error) {
 	gzipWriter, err := pgzip.NewWriterLevel(output, compressionLevel)
 	if err != nil {