add ContentFilteredTopic example.

[fujitatomoya]

should be linked to ROS 2 ContentFitleredTopic tutorial. (ros2/design#282)

related to ros2/demos#557

Signed-off-by: Tomoya Fujita Tomoya.Fujita@sony.com

[fujitatomoya]

just trying to use all interfaces provided by subscription content filtering here. and dealing with exceptions that might be generated via methods since users are likely to copy&paste the code from here to somewhere else.

[fujitatomoya]

CC: @wjwwood @ivanpauno @iuhilnehc-ynos

[wjwwood]

The example could be more "minimal" for copy-paste, but I think it's fine as-is to show more of how it could be used.

lgtm, with some suggestions addressed.

[fujitatomoya]

@wjwwood thanks for the comment, i borrowed your suggestions.

[fujitatomoya]

CI:

• Linux
• Linux-aarch64
• Windows

[fujitatomoya]

CI (address uncrustify errors):

• Linux
• Linux-aarch64
• Windows

[fujitatomoya]

example output for each rmw implementation.

• publisher (same binary with RMW_IMPLEMENTATION setting)

ros2 run examples_rclcpp_minimal_publisher publisher_member_function

• rmw_fastrtps (default)

# ros2 run examples_rclcpp_minimal_subscriber subscriber_content_filtering
[INFO] [1650647654.909896684] [minimal_contentfiltering_subscriber]: Subscribed to topic "/topic" with content filtering
[INFO] [1650647654.909990922] [minimal_contentfiltering_subscriber]: Content filtering expression and parameter are "data = %0" and "'Hello, world! 10'"
[INFO] [1650647663.337609015] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 10'
[INFO] [1650647663.338324998] [minimal_contentfiltering_subscriber]: Content filtering expression and parameter are "data = %0" and "'Hello, world! 20'"
[INFO] [1650647668.337454893] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 20'
[INFO] [1650647668.338167047] [minimal_contentfiltering_subscriber]: Content filtering expression and parameter are "data = %0" and "'Hello, world! 30'"
...<snip>

• rmw_connextdds

# RMW_IMPLEMENTATION=rmw_connextdds ros2 run examples_rclcpp_minimal_subscriber subscriber_content_filtering
RTI Connext DDS Non-commercial license is for academic, research, evaluation and personal use only. USE FOR COMMERCIAL PURPOSES IS PROHIBITED. See RTI_LICENSE.TXT for terms. Download free tools at rti.com/ncl. License issued to Non-Commercial User license@rti.com For non-production use only.
Expires on 00-jan-00 See www.rti.com for more information.
[INFO] [1650647909.339308552] [minimal_contentfiltering_subscriber]: Subscribed to topic "/topic" with content filtering
[INFO] [1650647909.339387411] [minimal_contentfiltering_subscriber]: Content filtering expression and parameter are "data = %0" and "'Hello, world! 10'"
[INFO] [1650647926.630042121] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 10'
[INFO] [1650647926.631364854] [minimal_contentfiltering_subscriber]: Content filtering expression and parameter are "data = %0" and "'Hello, world! 20'"
...<snip>

• rmw_cyclonedds

# RMW_IMPLEMENTATION=rmw_cyclonedds_cpp ros2 run examples_rclcpp_minimal_subscriber subscriber_content_filtering
[WARN] [1650647987.733083073] [minimal_contentfiltering_subscriber]: Content filter is not enabled since it's not supported
[INFO] [1650647990.514812843] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 0'
[INFO] [1650647991.014601673] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 1'
[INFO] [1650647991.514611925] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 2'
[INFO] [1650647992.014454205] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 3'
[INFO] [1650647992.514540176] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 4'
[INFO] [1650647993.014640461] [minimal_contentfiltering_subscriber]: I heard: 'Hello, world! 5'
...<snip>

[fujitatomoya]

Note: cross-vendor content filtering works between rmw_fastrtps and rmw_connextdds using this example.

[ivanpauno]

LGTM!

[fujitatomoya]

either @ivanpauno or @wjwwood , could you help to merge this? i do not have access permission for this repo.

[clalancette]

either @ivanpauno or @wjwwood , could you help to merge this? i do not have access permission for this repo.

Let's hold off until next week; we are trying to branch for Humble right now.

[fujitatomoya]

sorry, forgot that. thanks!

[wjwwood]

Yeah, this is ready, just waiting on Humble to unblock.

[fujitatomoya]

@clalancette could you merge this into master? so that i can link this example from ros2/ros2_documentation#2396 (release note).

[fujitatomoya]

@Mergifyio backport rolling humble

[mergify]

backport rolling humble

✅ Backports have been created

• Backport to branch rolling failed: Branch not found
• #342 add ContentFilteredTopic example. (backport #341) has been created for branch humble