Add the ability to override entrypoint

cirque/home/home.py

@@ -122,7 +122,7 @@ def add_device(self, device_config):
       device_node = WiFiAPNode(self.docker_client, base_image=base_image)
     else:
       device_node = DockerNode(
-          self.docker_client, device_type, capabilities, base_image=base_image)
+          self.docker_client, device_type, capabilities, entrypoint=device_config.get('entrypoint', None), base_image=base_image)
     device_node.run()
     if device_node.id is not None:
       self.home['devices'][device_node.id] = device_node

cirque/nodes/dockernode.py

@@ -25,7 +25,8 @@ def __init__(self,
                docker_client,
                node_type,
                capabilities=None,
-               base_image=None):
+               base_image=None,
+               entrypoint=None):
     self._client = docker_client
     self.node_type = node_type
     if base_image:
@@ -34,6 +35,7 @@ def __init__(self,
       self.image_name = node_type
     self.container = None
     self.capabilities = [] if capabilities is None else capabilities
+    self.entrypoint = entrypoint
     self.logger = CirqueLog.get_cirque_logger(self.__class__.__name__)
     self.logger.info('Capabilites: {}'.format(
         [c.name for c in self.capabilities]))
@@ -60,6 +62,8 @@ def merge_capapblity_arg(arg0, arg1):
     capability_run_args = reduce(merge_capapblity_arg, capability_run_args,
                                  {'cap_add': ['SYS_TIME']})
     kwargs.update(capability_run_args)
+    if self.entrypoint is not None:
+      kwargs['entrypoint'] = self.entrypoint
     self.container = self._client.containers.run(
         self.image_name, detach=True, **kwargs)
     self.logger.info('starting container with image {} args={}'.format(