Installing `ouster-ros` install lots of dev depencies.

[michaelcarlstrom-civrobotics]

Is your feature request related to a problem? Please describe.

Installing ouster-ros currently installs libboost-all-dev, libopencv-all-dev, and libpcl-all-dev.
From what I can tell these are coming from <depend>cv_bridge</depend>, <depend>pcl_ros</depend>, <depend>pcl_conversion</depend>.

Describe the solution you'd like
Could we move those packages to <build_depend> tags so that end users of the package do not need them installed.

Describe alternatives you've considered
Currently we have an apt remove in our CI to remove these packages after install ouster-ros which works but, is inelegant.

Targeted Platform (please complete the following information only if applicable, otherwise dot N/A):

[Samahu]

Totally

[Samahu]

@michaelcarlstrom-civrobotics which ROS port of the ouster-ros driver are you referring to (1 or 2)?

For ROS1 this is what we currently have (the pcl and boost both are marked as build_depend)

  <depend>roscpp</depend>
  <depend>std_msgs</depend>
  <depend>sensor_msgs</depend>
  <depend>geometry_msgs</depend>
  <depend>tf2_ros</depend>
  <depend>pcl_ros</depend>
  <depend>pcl_conversions</depend>
  <depend>cv_bridge</depend>

  <build_depend>boost</build_depend>
  <build_depend>nodelet</build_depend>
  <build_depend>libjsoncpp-dev</build_depend>
  <build_depend>eigen</build_depend>
  <build_depend>message_generation</build_depend>
  <build_depend>tf2_eigen</build_depend>
  <build_depend>libpcl-all-dev</build_depend>
  <build_depend>curl</build_depend>
  <build_depend>spdlog</build_depend>

  <exec_depend>nodelet</exec_depend>
  <exec_depend>libjsoncpp</exec_depend>
  <exec_depend>message_runtime</exec_depend>
  <exec_depend>topic_tools</exec_depend>
  <exec_depend>curl</exec_depend>
  <exec_depend>spdlog</exec_depend>

[michaelcarlstrom-civrobotics]

I was referring to the ros2 port. The problem I believe is you are using <depend> for cv_bridge, pcl_ros, and pcl_converion and not <build_depend> . These packages use the <build_export_depend> to leak these dependencies to upstream packages from my understanding to allow building. But it only leaks it for <build_depend> packages. But <depend> is shorthand for <build_depend>, <exec_depend>, and <test_depend>.

  <depend>rclcpp</depend>
  <depend>rclcpp_components</depend>
  <depend>rclcpp_lifecycle</depend>
  <depend>std_msgs</depend>
  <depend>ouster_sensor_msgs</depend>
  <depend>sensor_msgs</depend>
  <depend>geometry_msgs</depend>
  <depend>tf2_ros</depend>
  <depend>pcl_ros</depend>
  <depend>pcl_conversions</depend>
  <depend>std_srvs</depend>
  <depend>cv_bridge</depend>

  <build_depend>libjsoncpp-dev</build_depend>
  <build_depend>eigen</build_depend>
  <build_depend>tf2_eigen</build_depend>
  <build_depend>libpcl-all-dev</build_depend>
  <build_depend>curl</build_depend>
  <build_depend>libtins-dev</build_depend>
  <build_depend>spdlog</build_depend>

  <exec_depend>rosidl_default_runtime</exec_depend>
  <exec_depend>launch</exec_depend>
  <exec_depend>launch_ros</exec_depend>
  <exec_depend>libjsoncpp</exec_depend>
  <exec_depend>curl</exec_depend>
  <exec_depend>spdlog</exec_depend>
  <exec_depend>libtins-dev</exec_depend>

  <test_depend>gtest</test_depend>

[Samahu]

@michaelcarlstrom-civrobotics I am not sure these can actually be removed .. you see cv_bridge is a runtime dependency.

For pcl_conversions although itself can be viewed as build only dependency but the use of pcl::PCLPointCloud2 is required from PCL.

I am checking to see if we can drop pcl_ros form the list of deps (PR: #504)

[Samahu]

So the only package I ended up dropping is pcl_ros.. I think we can drop the cv_bridge in the future and replace it with something that doesn't depend on OpenCV as our use of it is very minimal .. I think it was mainly to load an image into an eigen matrix.

So will keep this open ticket open for now.

[michaelcarlstrom-civrobotics]

Thanks for looking into it!