From 6f7b06e66fe26902bdca6dc3303d5e4aec3a7a3c Mon Sep 17 00:00:00 2001
From: Julien Duponchelle <julien@duponchelle.info>
Date: Tue, 31 May 2016 16:32:12 +0200
Subject: [PATCH] Fix a crash when docker start command is None

Ref #550
---
 gns3server/modules/docker/docker_vm.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gns3server/modules/docker/docker_vm.py b/gns3server/modules/docker/docker_vm.py
index 6cc689b4..95656efa 100644
--- a/gns3server/modules/docker/docker_vm.py
+++ b/gns3server/modules/docker/docker_vm.py
@@ -129,8 +129,9 @@ class DockerVM(BaseVM):
 
     @start_command.setter
     def start_command(self, command):
-        command = command.strip()
-        if len(command) == 0:
+        if command:
+            command = command.strip()
+        if command is None or len(command) == 0:
             self._start_command = None
         else:
             self._start_command = command