This packages contains a set of wrappers classes and functions for common ROS operations.
Topic services are a wrappers over ROS topics that provide a service like functionality but in a much more introspectable way. Eg: There is no ros2 service echo and no way to view service clients in a running system.
The usage is very similar to that of standard ROS services and can even make use of the same service definitions. For most usages simply just substitute ros::ServiceServer or ros::ServiceClient for swri::TopicServiceServer or swri::TopicServiceClient in the declaration and use it in the same way.
In order to generate the backing topics for a Topic Service from a service message add a generate_topic_service_files block to your project's CMakeList.txt and use it almost the same way you would an rosidl_generate_interfaces block. This generates the individual topic service messages and returns a list of these to the variable named by the first argument. Make sure to add these to your rosidl_generate_interfaces call along with the marti_common_msgs dependency.
Make sure to add swri_roscpp as a dependency to your message project.
For example:
generate_topic_service_files(generated_message_list
DIRECTORY topic_srv
FILES
ClearActiveRoute.srv
DeleteRoute.srv
GetRoute.srv
GetRouteNames.srv
SaveRoute.srv
SetActiveRoute.srv
SetRoute.srv
SetNextCheckpoint.srv
)
rosidl_generate_interfaces(${PROJECT_NAME}
your_other_messages_here.msg
${generated_message_list}
DEPENDENCIES
${MSG_DEPS}
marti_common_msgs
)To use the generated topics simply include your_project/srv/your_service.h. They have response and request fields just like normal services.
Note: This package's dynamic parameter implementation has been deprecated and removed; it is unnecessary in ROS 2 Dashing and rclcpp::Node::declare_parameter provides an equivalent alternative.