vm: add workdir_template functionality

The new manager config argument workdir_template refers to a directory. Optional.
Each VM will get a recursive copy of the files that are present in workdir_template.
VM config can then use these private copies as needed. The copy directory
can be referenced with "{{TEMPLATE}}" string. This is different from using
the files directly in that each instance will get own clean, private,
scratch copy of the files. Currently supported only for qemu_args argument
of qemu VM type. Use example:
Create a template dir with necessary files:
$ mkdir /mytemplatedir
$ truncate -s 64K /mytemplatedir/fd
Then specify the dir in the manager config:
	"workdir_template": "/mytemplatedir"
Then use these files in VM config:
	"qemu_args": "-fda {{TEMPLATE}}/fd"

1 files changed, 24 insertions, 0 deletions

diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index 32a8054e7..0bc257e76 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -163,6 +163,30 @@ func CopyFiles(srcDir, dstDir string, files map[string]bool) error {
 	return os.Rename(tmpDir, dstDir)
 }
 
+func CopyDirRecursively(srcDir, dstDir string) error {
+	if err := MkdirAll(dstDir); err != nil {
+		return err
+	}
+	files, err := ioutil.ReadDir(srcDir)
+	if err != nil {
+		return err
+	}
+	for _, file := range files {
+		src := filepath.Join(srcDir, file.Name())
+		dst := filepath.Join(dstDir, file.Name())
+		if file.IsDir() {
+			if err := CopyDirRecursively(src, dst); err != nil {
+				return err
+			}
+			continue
+		}
+		if err := CopyFile(src, dst); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // LinkFiles creates hard links for files from dstDir to srcDir.
 // Files are assumed to be relative names in slash notation.
 // All other files in dstDir are removed.