ros1-melodic-to-ros2-dashing-with-custom-messages

This repo demonstrates the following:

• a custom ROS2 interfaces package ros2_ws/src/gateway_interfaces
• a custom ROS1 interfaces package ros1_ws/src/gateway_msgs
• building a custom ros1_bridge package referencing the above two packages
• some tests

How do I set up my environment?

Assumptions

• MacOS
• CLion
• ROS2 already installed

Steps

• in a terminal, before you've opened CLion
  • (change directory to the root of this repo)
  • cd ros2_ws/src
  • source ~/ros2_install/ros2-osx/setup.bash
    • this adjusts your environment for building ROS2 packages
  • colcon build --symlink-install
    • this generates build and install folders with headers / libraries etc for the messages
  • source install/setup.bash
    • this adjusts your environment for this ROS2 workspace
  • /Applications/CLion.app/Contents/MacOS/clion
    • open this repo, point at the base CMakeLists.txt
  • you should now have header / library code completion

How do I build it?

• ./build.sh
  • builds the gateway_msgs package for ROS1
  • builds the gateway_interfaces package for ROS2
  • builds the ros1_gateway for ROS2 (which references the two above)
  • builds the gateway_pub_sub for ROS1 (which references the gateway_msgs package)
  • builds the gateway_pub_sub for ROS2 (which references the gateway_interfaces package)

How to I test it?

• ./test.sh
  • for gateway_pub_sub for ROS1
    • runs a ROS1 container, including:
      • the roscore daemon
      • the some_request_to_some_response.py node
    • runs the integration tests inside that container against that node
  • for gateway_pub_sub for ROS2
    • runs a ROS2 container, including:
      • the some_request_to_some_response.py node
    • runs the integration tests inside that container against that node
  • for gateway_pub_sub for ROS1 (tested from ROS2 via ros1_bridge)
    • runs a ROS1 container, including:
      • the roscore daemon
      • the some_request_to_some_response.py node
    • runs a ROS2 container, including:
      • runs the integration tests inside that container against that node
  • for gateway_pub_sub for ROS2 (tested from ROS1 via ros1_bridge)
    • runs a ROS2 container, including:
      • the some_request_to_some_response.py node
    • runs a ROS1 container, including:
      • the roscore daemon
      • runs the integration tests inside that container against that node

Folder breakdown (in logical order)

• ros1_ws - ROS1 workspace for gateway_msgs (ROS1 interface package) and gateway_pub_sub (example ROS1 implementation)
  • notable files for gateway_msgs:
    • gateway_msgs/package.xml - package definition for catalogue purposes
    • gateway_msgs/CMakeLists.xml - package definition for build purposes
    • gateway_msgs/msg/SomeRequest.msg
    • gateway_msgs/msg/SomeRequest.msg
  • notable files for gateway_pub_sub:
    • gateway_pub_sub/package.xml - package definition for catalogue purposes
    • gateway_pub_sub/CMakeLists.xml - package definition for build purposes
    • gateway_pub_sub/scripts/some_request_to_some_response.py - ROS node that subscribes to some_request : SomeRequest and publishes to some_response : SomeResponse per each subscription callback
    • gateway_pub_sub/tests/some_request_to_some_response_test.py - integration test using rospy to communicate with the node above (assumes it's already running)
• ros2_ws - ROS1 workspace for gateway_interfaces (ROS2 interface package) and gateway_pub_sub (example ROS1 implementation)
  • notable files for gateway_interfaces:
    • gateway_interfaces/package.xml - package definition for catalogue purposes
    • gateway_interfaces/CMakeLists.xml - package definition for build purposes
    • gateway_interfaces/msg/SomeRequest.msg
    • gateway_interfaces/msg/SomeRequest.msg
  • notable files for gateway_pub_sub:
    • gateway_pub_sub/package.xml - package definition for catalogue purposes
    • gateway_pub_sub/CMakeLists.xml - package definition for build purposes
    • gateway_pub_sub/scripts/some_request_to_some_response.py - ROS node that subscribes to some_request : SomeRequest and publishes to some_response : SomeResponse per each subscription callback
    • gateway_pub_sub/tests/some_request_to_some_response_test.py - integration test using rclpy to communicate with the node above (assumes it's already running)

Takeaways

• if you want to generate messages externally...
  • you'll need to generate them in both ROS1 and ROS2 formats and place them in the following locations:
    • ros1_ws/src/gateway_msg/msg
    • ros2_ws/src/gateway_interfaces/msg
  • you'll also need to update CMakeLists.txt for each package to reference the new messages files
  • finally you'll need to recompile the ros1_gateway package (so just re-run build.sh)
• adjacent ROS1 nodes need to be made aware of a roscore via the ROS_MASTER_URI environment variable (default http://localhost:11311)
  • if you want to do multi-container testing, you'll need to handle hostnames and adjust the ROS_MASTER_URI environment variable as applicable
• there aren't any reliable methods to wait for a Publisher to be ready (so a sleep is used in the tests)
• there are some unknowns about how ROS2's QoS maps to ROS1's