From 30dea40a20e45bdb0d32fd7c373f07e1dccbe794 Mon Sep 17 00:00:00 2001
From: Tom Fawssett <tom.fawssett@gmail.com>
Date: Sat, 24 Jun 2017 16:01:12 +0100
Subject: Move file system archive code into backup package

---
 system/backup/archive.go | 95 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 system/backup/archive.go

(limited to 'system/backup/archive.go')

diff --git a/system/backup/archive.go b/system/backup/archive.go
new file mode 100644
index 0000000..0a8b964
--- /dev/null
+++ b/system/backup/archive.go
@@ -0,0 +1,95 @@
+package backup
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// ArchiveFS walks the filesystem starting from basedir writing files encountered
+// tarred and gzipped to the provided writer
+func ArchiveFS(ctx context.Context, basedir string, w io.Writer) error {
+	gz := gzip.NewWriter(w)
+	tarball := tar.NewWriter(gz)
+
+	errChan := make(chan error, 1)
+	walkFn := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		hdr, err := tar.FileInfoHeader(info, "")
+		if err != nil {
+			return err
+		}
+
+		hdr.Name = path
+
+		err = tarball.WriteHeader(hdr)
+		if err != nil {
+			return err
+		}
+
+		if !info.IsDir() {
+			src, err := os.Open(path)
+			if err != nil {
+				return err
+			}
+			defer src.Close()
+
+			_, err = io.Copy(tarball, src)
+			if err != nil {
+				return err
+			}
+
+			err = tarball.Flush()
+			if err != nil {
+				return err
+			}
+
+			err = gz.Flush()
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+
+	// stop processing if we get a cancellation signal
+	err := filepath.Walk(basedir, func(path string, info os.FileInfo, err error) error {
+		go func() { errChan <- walkFn(path, info, err) }()
+
+		select {
+		case <-ctx.Done():
+			if err := ctx.Err(); err != nil {
+				return err
+			}
+		case err := <-errChan:
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+	if err != nil {
+		fmt.Println(err)
+		return err
+	}
+
+	err = gz.Close()
+	if err != nil {
+		return err
+	}
+	err = tarball.Close()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
-- 
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