playing with ideas...

Makefile

@@ -2,9 +2,10 @@ format:
 	gofmt -s -w *.go
 test:
 	sudo `which go` test -v
+test_clone:
+	sudo `which go` test -run TestClone -v
 test_concurrent:
 	sudo `which go` test -run TestConcurrentDefined_Negative -v
 	sudo `which go` test -run TestConcurrentCreate -v
 	sudo `which go` test -run TestConcurrentDefined_Positive -v
 	sudo `which go` test -run TestConcurrentDestroy -v
-

backend.go

@@ -0,0 +1,46 @@
+/*
+ * backend.go: Go bindings for lxc
+ *
+ * Copyright © 2013, S.Çağlar Onur
+ *
+ * Authors:
+ * S.Çağlar Onur <caglar@10ur.org>
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+package lxc
+
+type Backend int
+const (
+        BTRFS Backend = iota
+        DIRECTORY
+        LVM
+        OVERLAYFS
+)
+
+// Backend as string
+func (t Backend) String() string {
+	switch t {
+	case DIRECTORY:
+		return "Directory"
+	case BTRFS:
+		return "BtrFS"
+	case LVM:
+		return "LVM"
+	case OVERLAYFS:
+		return "OverlayFS"
+	}
+	return "<INVALID>"
+}

container.go

@@ -31,7 +31,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
-//	"syscall"
+	//	"syscall"
 	"sync"
 	"unsafe"
 )
@@ -167,6 +167,22 @@ func (lxc *Container) Destroy() bool {
 	return bool(C.lxc_container_destroy(lxc.container))
 }
 
+// FIXME: consider other parameters
+// FIXME: Clone or CloneToOverlayFS, CloneToLVM, SnapshotToLVM etc?
+func (lxc *Container) Clone(name string, backend Backend) bool {
+	lxc.Lock()
+	defer lxc.Unlock()
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	if backend == OVERLAYFS {
+		return bool(C.lxc_container_clone(lxc.container, cname, C.int(LXC_CLONE_SNAPSHOT), C.CString("overlayfs")))
+	} else {
+		return bool(C.lxc_container_clone(lxc.container, cname, 0, nil))
+	}
+}
+
 // Waits till the container changes its state or timeouts
 func (lxc *Container) Wait(state State, timeout int) bool {
 	lxc.Lock()

lxc.c

@@ -148,3 +148,7 @@ bool lxc_container_load_config(struct lxc_container *c, char *alt_file) {
 bool lxc_container_save_config(struct lxc_container *c, char *alt_file) {
 	return c->save_config(c, alt_file);
 }
+
+bool lxc_container_clone(struct lxc_container *c, const char *newname, int flags, const char *bdevtype) {
+    return c->clone(c, newname, NULL, flags, bdevtype, NULL, 0) != NULL;
+}

lxc.go

@@ -44,12 +44,27 @@ const (
 	LXC_NETWORK_KEY = "lxc.network"
 )
 
+const (
+	LXC_CLONE_KEEPNAME int = 1 << iota
+	LXC_CLONE_COPYHOOKS
+	LXC_CLONE_KEEPMACADDR
+	LXC_CLONE_SNAPSHOT
+)
+
 func NewContainer(name string) *Container {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 	return &Container{container: C.lxc_container_new(cname, nil)}
 }
 
+func GetContainer(lxc *Container) bool {
+	return C.lxc_container_get(lxc.container) == 1
+}
+
+func PutContainer(lxc *Container) bool {
+	return C.lxc_container_put(lxc.container) == 1
+}
+
 // Returns LXC version
 func Version() string {
 	return C.GoString(C.lxc_get_version())

lxc.h

@@ -44,3 +44,5 @@ extern const char* lxc_container_get_config_path(struct lxc_container *);
 extern const char* lxc_container_state(struct lxc_container *);
 extern pid_t lxc_container_init_pid(struct lxc_container *);
 extern void lxc_container_want_daemonize(struct lxc_container *);
+
+extern bool lxc_container_clone(struct lxc_container *, const char *, int, const char *);

lxc_test.go

@@ -38,6 +38,21 @@ const (
 	CONFIG_FILE_NAME = "/var/lib/lxc/rubik/config"
 )
 
+func TestClone(t *testing.T) {
+	z := NewContainer("caglar")
+	z.Destroy()
+	PutContainer(z)
+
+	z = NewContainer("caglar-overlayfs")
+	z.Destroy()
+	PutContainer(z)
+
+	z = NewContainer("bleach")
+	t.Logf("Clone %v\n", z.Clone("caglar", DIRECTORY))
+	t.Logf("Clone %v\n", z.Clone("caglar-overlayfs", OVERLAYFS))
+	PutContainer(z)
+}
+
 func init() {
 	runtime.GOMAXPROCS(runtime.NumCPU())
 }