Tools: update ROS 2 README

[srmainwaring]

Improvements to the ROS 2 launch instructions.

Closes #23549

Details

• Correct paths to ros2.repos file.
• Improve build and install instructions.

[Ryanf55]

If you didn't build all the dependnecies, I see this test hanging. Shall I create a bug?

ryan@ryan-B650:~/Development/ardu_test_ws$ colcon test --packages-select ardupilot_dds_tests --event-handlers=console_direct+
Starting >>> ardupilot_dds_tests
============================= test session starts ==============================
platform linux -- Python 3.10.6, pytest-6.2.5, py-1.10.0, pluggy-0.13.0
cachedir: /home/ryan/Development/ardu_test_ws/build/ardupilot_dds_tests/.pytest_cache
rootdir: /home/ryan/Development/ardu_test_ws/src/ardupilot/Tools/ros2/ardupilot_dds_tests
plugins: launch-testing-1.0.4, ament-xmllint-0.12.5, ament-lint-0.12.5, launch-testing-ros-0.19.4, ament-pep257-0.12.5, ament-copyright-0.12.5, launch-pytest-1.0.4, ament-flake8-0.12.5, cov-3.0.0, colcon-core-0.12.1
collecting ...                                    
collected 6 items                                                              

test/test_copyright.py .                                                 [ 16%]
test/test_flake8.py .                                                    [ 33%]
test/test_pep257.py .                                                    [ 50%]
test/ardupilot_dds_tests/test_navsat_msg_received.py E                   [ 66%]
test/ardupilot_dds_tests/test_time_msg_received.py E                     [ 83%]
[Processing: ardupilot_dds_tests]                   
[Processing: ardupilot_dds_tests]                           
[Processing: ardupilot_dds_tests]                             
[Processing: ardupilot_dds_tests]                             
[Processing: ardupilot_dds_tests]                             
test/ardupilot_dds_tests/test_virtual_ports.py E                         [100%]

==================================== ERRORS ====================================
_________________ ERROR at setup of test_navsat_msgs_received __________________
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:58: in get_package_prefix
    content, package_prefix = get_resource('packages', package_name)
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/resources.py:86: in get_resource
    raise LookupError(
E   LookupError: Could not find the resource 'ardupilot_sitl' of type 'packages'

During handling of the above exception, another exception occurred:
test/ardupilot_dds_tests/conftest.py:117: in sitl_dds
    get_package_share_directory("ardupilot_sitl"),
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:80: in get_package_share_directory
    path = os.path.join(get_package_prefix(package_name), 'share', package_name)
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:60: in get_package_prefix
    raise PackageNotFoundError(
E   ament_index_python.packages.PackageNotFoundError: "package 'ardupilot_sitl' not found, searching: ['/home/ryan/Development/ardu_test_ws/install/ardupilot_dds_tests', '/opt/ros/humble']"
---------------------------- Captured stdout setup -----------------------------

tmpdirname: /tmp/pytest-of-ryan/pytest-1/devices0

__________________ ERROR at setup of test_time_msgs_received ___________________
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:58: in get_package_prefix
    content, package_prefix = get_resource('packages', package_name)
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/resources.py:86: in get_resource
    raise LookupError(
E   LookupError: Could not find the resource 'ardupilot_sitl' of type 'packages'

During handling of the above exception, another exception occurred:
test/ardupilot_dds_tests/conftest.py:117: in sitl_dds
    get_package_share_directory("ardupilot_sitl"),
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:80: in get_package_share_directory
    path = os.path.join(get_package_prefix(package_name), 'share', package_name)
/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py:60: in get_package_prefix
    raise PackageNotFoundError(
E   ament_index_python.packages.PackageNotFoundError: "package 'ardupilot_sitl' not found, searching: ['/home/ryan/Development/ardu_test_ws/install/ardupilot_dds_tests', '/opt/ros/humble']"
---------------------------- Captured stdout setup -----------------------------

tmpdirname: /tmp/pytest-of-ryan/pytest-1/devices1

_____________________ ERROR at setup of test_virtual_ports _____________________
/opt/ros/humble/lib/python3.10/site-packages/launch_pytest/plugin.py:369: in run_until_complete
    loop.run_until_complete(future_like)
/usr/lib/python3.10/asyncio/base_events.py:633: in run_until_complete
    self.run_forever()
/usr/lib/python3.10/asyncio/base_events.py:600: in run_forever
    self._run_once()
/usr/lib/python3.10/asyncio/base_events.py:1860: in _run_once
    event_list = self._selector.select(timeout)
/usr/lib/python3.10/selectors.py:469: in select
    fd_event_list = self._selector.poll(timeout, max_ev)
E   KeyboardInterrupt

During handling of the above exception, another exception occurred:
/opt/ros/humble/lib/python3.10/site-packages/launch_pytest/plugin.py:127: in pytest_fixture_setup
    run_until_complete(event_loop, event.wait())
/opt/ros/humble/lib/python3.10/site-packages/launch_pytest/plugin.py:371: in run_until_complete
    if future_like.done() and not future_like.cancelled():
E   AttributeError: 'coroutine' object has no attribute 'done'
---------------------------- Captured stdout setup -----------------------------

tmpdirname: /tmp/pytest-of-ryan/pytest-1/devices2

[INFO] [launch]: All log files can be found below /home/ryan/.ros/log/2023-04-22-09-52-35-879217-ryan-B650-96148
[INFO] [launch]: Default logging verbosity is set to INFO
[ERROR] [launch]: Caught exception in launch (see debug for traceback): "package 'ardupilot_sitl' not found, searching: ['/home/ryan/Development/ardu_test_ws/install/ardupilot_dds_tests', '/opt/ros/humble']"
[INFO] [echo-1]: process started with pid [96187]
[INFO] [echo-1]: process has finished cleanly [pid 96187]
- generated xml file: /home/ryan/Development/ardu_test_ws/build/ardupilot_dds_tests/pytest.xml -
=========================== short test summary info ============================
ERROR test/ardupilot_dds_tests/test_navsat_msg_received.py::test_navsat_msgs_received
ERROR test/ardupilot_dds_tests/test_time_msg_received.py::test_time_msgs_received
ERROR test/ardupilot_dds_tests/test_virtual_ports.py::test_virtual_ports - At...
=================== 3 passed, 3 errors in 158.84s (0:02:38) ====================
Aborted  <<< ardupilot_dds_tests [2min 39s]

Summary: 0 packages finished [2min 40s]
  1 package aborted: ardupilot_dds_tests
  1 package had test failures: ardupilot_dds_tests

[srmainwaring]

Shall I create a bug?

Yes - I think the entire test needs a timer event handler added, and events cause a failure if any of the processes fail before the test completes. Good to get the edge cases pinned down before we apply the approach to other messages.

Raised #23577

[Ryanf55]

See #23576

[srmainwaring]

@Ryanf55 this is good to go. We'll track the hanging tests issue separately, but shouldn't affect the docs update. Would be good to have the wget ref pointing to the correct repo in master.