1 files changed, 22 insertions, 0 deletions
diff --git a/pkg/specgenutil/ports.go b/pkg/specgenutil/ports.go
new file mode 100644
index 000000000..6cc4de1ed
--- /dev/null
+++ b/pkg/specgenutil/ports.go
@@ -0,0 +1,22 @@
+package specgenutil
+
+import (
+	"github.com/docker/go-connections/nat"
+	"github.com/pkg/errors"
+)
+
+func verifyExpose(expose []string) error {
+	// add the expose ports from the user (--expose)
+	// can be single or a range
+	for _, expose := range expose {
+		// support two formats for expose, original format <portnum>/[<proto>] or <startport-endport>/[<proto>]
+		_, port := nat.SplitProtoPort(expose)
+		// parse the start and end port and create a sequence of ports to expose
+		// if expose a port, the start and end port are the same
+		_, _, err := nat.ParsePortRange(port)
+		if err != nil {
+			return errors.Wrapf(err, "invalid range format for --expose: %s", expose)
+		}
+	}
+	return nil
+}