Adds a timeout feature to rostopic echo

[arjo129]

Builds on top of:

• Refactor common types #791 - Review and merge this and you'll see the change is minimal.

This PR adds a --time-out feature which allows you to set the amount of time that rostopic echo should wait. This feature was
requested by #529, however, we only added --once and no time out. I have a use case where this timeout could be useful hence I added it

Signed-off-by: Arjo Chakravarty arjo@openrobotics.org

[fujitatomoya]

test would be ideal, to check certain published messages are printed in specific time window until it times out.

[fujitatomoya]

test would be ideal, to check certain published messages are printed in specific time window until it times out.

i think you can refer to,

ros2cli/ros2topic/test/test_echo_pub.py

Lines 393 to 435 in cf020c0

	@launch_testing.markers.retry_on_failure(times=5)
	def test_echo_once(self, launch_service, proc_info, proc_output):
	topic = '/clitest/topic/echo_once'
	publisher = self.node.create_publisher(String, topic, 10)
	assert publisher
	def publish_message():
	publisher.publish(String(data='hello'))
	publish_timer = self.node.create_timer(1.0, publish_message)
	try:
	command_action = ExecuteProcess(
	cmd=['ros2', 'topic', 'echo', '--once', topic, 'std_msgs/msg/String'],
	additional_env={
	'PYTHONUNBUFFERED': '1'
	},
	output='screen'
	)
	with launch_testing.tools.launch_process(
	launch_service, command_action, proc_info, proc_output,
	output_filter=launch_testing_ros.tools.basic_output_filter(
	filtered_rmw_implementation=get_rmw_implementation_identifier()
	)
	) as command:
	# The future won't complete - we will hit the timeout
	self.executor.spin_until_future_complete(
	rclpy.task.Future(), timeout_sec=3
	)
	assert command.wait_for_shutdown(timeout=5)
	assert launch_testing.tools.expect_output(
	expected_lines=[
	'data: hello',
	'---',
	],
	text=command.output,
	strict=True
	)
	finally:
	# Cleanup
	self.node.destroy_timer(publish_timer)
	self.node.destroy_publisher(publisher)

[arjo129]

Thanks! Working on it.

[clalancette]

This looks good to me. I'll run CI on it next.

But I'd like to get @fujitatomoya's opinion before I merge.

[clalancette]

CI:

• Linux
• Linux-aarch64
• Windows

[fujitatomoya]

@arjo129 LTGM!