def execute(
self,
context: LaunchContext
) -> Optional[List[Action]]:
"""Execute the action."""
# resolve target container node name
if is_a_subclass(self.__target_container, ComposableNodeContainer):
self.__final_target_container_name = self.__target_container.node_name
elif isinstance(self.__target_container, SomeSubstitutionsType_types_tuple):
subs = normalize_to_list_of_substitutions(self.__target_container)
self.__final_target_container_name = perform_substitutions(
context, subs)
else:
self.__logger.error(
'target container is neither a ComposableNodeContainer nor a SubstitutionType')
return
# Create a client to load nodes in the target container.
self.__rclpy_load_node_client = get_ros_node(context).create_client(
composition_interfaces.srv.LoadNode, '{}/_container/load_node'.format(
self.__final_target_container_name
)
)
context.add_completion_future(
context.asyncio_loop.run_in_executor(
None, self._load_in_sequence, self.__composable_node_descriptions, context
)
)
def execute(self, context: LaunchContext) -> Optional[List[Action]]:
"""Execute the action."""
# resolve target container node name
if is_a_subclass(self.__target_container, ComposableNodeContainer):
self.__final_target_container_name = self.__target_container.node_name
elif isinstance(self.__target_container,
SomeSubstitutionsType_types_tuple):
subs = normalize_to_list_of_substitutions(self.__target_container)
self.__final_target_container_name = perform_substitutions(
context, subs)
else:
self.__logger.error(
'target container is neither a ComposableNodeContainer nor a SubstitutionType'
)
return
# Create a client to load nodes in the target container.
self.__rclpy_load_node_client = get_ros_node(context).create_client(
composition_interfaces.srv.LoadNode,
'{}/_container/load_node'.format(
self.__final_target_container_name))
# Generate load requests before execute() exits to avoid race with context changing
# due to scope change (e.g. if loading nodes from within a GroupAction).
load_node_requests = [
get_composable_node_load_request(node_description, context)
for node_description in self.__composable_node_descriptions
]
context.add_completion_future(
context.asyncio_loop.run_in_executor(None, self._load_in_sequence,
load_node_requests, context))
def _load_in_sequence(self,
composable_node_descriptions: List[ComposableNode],
context: LaunchContext) -> None:
"""
Load composable nodes sequentially.
:param composable_node_descriptions: descriptions of composable nodes to be loaded
:param context: current launch context
"""
next_composable_node_description = composable_node_descriptions[0]
composable_node_descriptions = composable_node_descriptions[1:]
self._load_node(next_composable_node_description, context)
if len(composable_node_descriptions) > 0:
context.add_completion_future(
context.asyncio_loop.run_in_executor(
None, self._load_in_sequence, composable_node_descriptions,
context))
def _load_in_sequence(self, load_node_requests: List[
composition_interfaces.srv.LoadNode.Request],
context: LaunchContext) -> None:
"""
Load composable nodes sequentially.
:param composable_node_descriptions: descriptions of composable nodes to be loaded
:param context: current launch context
"""
next_load_node_request = load_node_requests[0]
load_node_requests = load_node_requests[1:]
self._load_node(next_load_node_request, context)
if len(load_node_requests) > 0:
context.add_completion_future(
context.asyncio_loop.run_in_executor(None,
self._load_in_sequence,
load_node_requests,
context))