Added support for filtering topics via regular expressions

[esteve]

This PR adds a new option --topics-regex that allows filtering topics via regular expressions.

[esteve]

I'm debugging an issue with the player and regular expressions. The following causes ros2 bag play to throw an exception:

$ ros2 bag play . --topics-regex /lidar_front/points_raw
[INFO] [1656517413.919186963] [rosbag2_storage]: Opened database './rosbag2_2020_09_23-15_58_07.db3' for READ_ONLY.
[INFO] [1656517413.919316194] [rosbag2_player]: Set rate to 1
[INFO] [1656517413.925218047] [rosbag2_player]: Adding keyboard callbacks.
[INFO] [1656517413.925259647] [rosbag2_player]: Press SPACE for Pause/Resume
[INFO] [1656517413.925286814] [rosbag2_player]: Press CURSOR_RIGHT for Play Next Message
[INFO] [1656517413.925312879] [rosbag2_player]: Press CURSOR_UP for Increase Rate 10%
[INFO] [1656517413.925341094] [rosbag2_player]: Press CURSOR_DOWN for Decrease Rate 10%
[INFO] [1656517413.925446615] [rosbag2_player]: Playback until timestamp: -1
[INFO] [1656517413.925790959] [rosbag2_storage]: Opened database './rosbag2_2020_09_23-15_58_07.db3' for READ_ONLY.
[ERROR] [1656517414.026479569] [rosbag2_player]: Failed to play: Error when preparing SQL statement 'SELECT data, timestamp, topics.name, messages.id FROM messages JOIN topics ON messages.topic_id = topics.id WHERE ((topics.name REGEXP '/lidar_front/points_raw')) AND (((timestamp = 1600901887524769241) AND (messages.id >= 0)) OR (timestamp > 1600901887524769241)) ORDER BY messages.timestamp, messages.id;'. SQLite error: (1): SQL logic error

however, when issuing that same query directly via the sqlite3 command line interface, I get the correct results.

[esteve]

It seems that for the REGEXP operator to work an application-defined function needs to be provided. I'm guessing that the sqlite3 command line tool already includes one, so in this case it'd be a matter of defining one in the C++ code.

[esteve]

This now works, you can pass multiple arguments to --topics-regex and ros2 bag play will only play the topics that match the regular expressions (e.g. --topics-regex /lidar_.*/points_raw)

[jhdcs]

This looks okay to me, though I wouldn't mind a second opinion from another reviewer.

[MichaelOrlov]

This looks okay to me, though I wouldn't mind a second opinion from another reviewer.

I will review it in a couple days.

[MichaelOrlov]

@esteve Overall looks good to me.
Among one nitpick with pointers initialization.
Also could you please write a few unit tests to cover new topics_regex API ?

[esteve]

@MichaelOrlov I've added a test based on the the existing topics API, does it look enough or would you like more tests? Thanks.

[MichaelOrlov]

@esteve Thank you for your contribution!
Now it looks good. Approving.

[MichaelOrlov]

Running CI:
Gist: https://gist.githubusercontent.com/MichaelOrlov/4902ef223bb586d0f7311fd7508bc496/raw/28022ca5ed769da33c9731136f0d03173f8dec13/ros2.repos
BUILD args: --packages-above-and-dependencies ros2bag rosbag2_py rosbag2_storage rosbag2_storage_default_plugins rosbag2_transport rosbag2_tests
TEST args: --packages-above ros2bag rosbag2_py rosbag2_storage rosbag2_storage_default_plugins rosbag2_transport rosbag2_tests
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/10473

• Linux
• Linux-aarch64
• Windows

[ros-discourse]

This pull request has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/ros-2-tsc-meeting-minutes-8-18-2022/27050/1