lxd/network/openvswitch/shared: Add the vsctl function

vsctl is a simple wrapper to call ovs-vsctl with args but conditionally adding
the '--db=unix:/...' arg if a bootstrapped MicroOVN deployment has been detected.

Signed-off-by: Gabriel Mougard <[email protected]>

lxd/network/openvswitch/shared.go

@@ -1,13 +1,26 @@
 package openvswitch
 
 import (
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
 )
 
 var MicroovnTargetChassisPath = regexp.MustCompile(`^/var/snap/lxd/[0-9]+/microovn/chassis/switch`)
 
+// vsctl either returns the "ovs-vsctl" command if OVN is built in with LXD
+// or if MicroOVN is installed and the 'ovn-chassis' content interface is connected,
+// it returns "ovs-vsctl" with its southbound db unix socket.
+func vsctl(args ...string) (string, []string) {
+	targetPath, _ := os.Readlink("/run/openvswitch")
+	if !MicroovnTargetChassisPath.MatchString(targetPath) {
+		return "ovs-vsctl", args
+	}
+
+	return "ovs-vsctl", append([]string{fmt.Sprintf("--db=unix:%s/db.sock", targetPath)}, args...)
+}
+
 // unquote passes s through strconv.Unquote if the first character is a ", otherwise returns s unmodified.
 // This is useful as openvswitch's tools can sometimes return values double quoted if they start with a number.
 func unquote(s string) (string, error) {