fix index out of range when parsing output from shell_scripts/get.sh

capsulflask/virt_model.py

@@ -96,6 +96,9 @@ class ShellScriptVirtualization(VirtualizationInterface):
     completedProcess = run([join(current_app.root_path, 'shell_scripts/get.sh'), id], capture_output=True)
     self.validate_completed_process(completedProcess)
     lines = completedProcess.stdout.splitlines()
+    if len(lines) == 0:
+      return None
+
     ipaddr = lines[0].decode("utf-8")
 
     if not re.match(r"^([0-9]{1,3}\.){3}[0-9]{1,3}$", ipaddr):