I am currently using a Turtlebot3, completely set up following this guide: https://emanual.robotis.com/docs/en/p Running: ubuntu-18.04.3-preinstalled-server-arm64+raspi3.img.xz Already on GitHub? When I ssh into the Turtlebot3 and run the following command: ros2 launch turtlebot3_bringup robot.launch.py. Version or commit hash: ros2 topic list lists topic names with registered publishers or subscribers on the ROS 2 network. In this section an outline of the proposed constrains for ROS 2 topic and service names will be enumerated along with rationales where appropriate. 2 comments DavidATapia commented on Feb 25, 2021 edited Bug report Operating System: Ubuntu 20.04 (focal-20210119) Installation type: Debians Version or commit hash: 16.2.1. Thus, you can gain a lot of development time. On my REMOTE PC (desktop), I am running Ubuntu 18.04, also with ROS2 Dashing installed. data: hello world---data: hello world---. Hangs with the call: topicList.py: ln25: with NodeStrategy(args) as node That's because we are currently doing "P2P" discovery on the backend, and if you create a Node and call get_topic_names_and_types on it right away, discovery may not have happened yet. The new version v2 of Discovery Server, available from Fast DDS v2.0.2, implements a new filter feature that allows to further reduce the number of discovery messages sent. to your account, Operating System: I tried the methodrclcpp::Node::get_node_names() taken from: ros2 param list and ros2 node list should at least return and not hang. Ctrl+C does not take me back to the console (i.e. The command-line tools get around this a different way. A node may publish data to any number of topics and simultaneously have subscriptions to any number of topics. And if you run the command rostopic info /chatter, you will see that this topic is used by 2 nodes, talker and listener, talker is a publisher and listener a subscriber. We find the topics "data_1", "data_2" and "data_3". This is also the case if the first time I try the command: or any other ROS2 command. When this problem occur, you should restart ros2 daemon with following commands. When is tried to install 'netifaces' it is saying that already installed. The following schema represents the decrease of the discovery . A node will listen (subscribe) to a topic, or it will publish data on a topic. You may want to think about architecting something more like that; currently rapidly creating Nodes doesn't always do the discovery you want (as you discovered). ros2 topic persisting more than one message 0 ROS2 topic list does not show all available topics running on network 1 double free or corruption (out) error at the end of ROS2 C++ subscriber callback function when used with PCL Hot Network Questions Make phone calls from desktop computer Accuracy score of my KNN model is constant as k increases? Similarly, hidden parameters could be added. ros2 topic list # Will not list hidden topics. Leaving me to kill the daemon constantly. This is also the case if the first time I try the command: These are both in Python, but the method is the same in C++. Local time is now: Tue Dec 15 23:56:42 MSK 2020. $ ros2 daemon stop ros2 topic --include-hidden-topics list # Will list hidden topics. micro_ros_setup No definition of [python3-vcstool] for OS [osx], Print complete message received in ROS2 C++ subscriber callback, Define custom messages in python package (ROS2), Incorrect Security Information - Docker GUI. ROS 2 breaks complex systems down into many modular nodes. My talker and receiver are working properly. It may make sense to add a timeout to get_topic_names_and_types; I'm not sure. Sign in From there you can: From the terminal, listen to any topic with ros2 topic echo and see what's going on. Rebooting the system helped to solve the issue though. The pathnames in your output above all have the word "crystal" in it. How to list the ros2 topics from a c++ node? These are both in Python, but the method is the same in C++. List the active topics. I'm using the latest master branch 5c11d640a49f1a1caa0de8add4e4c782d3a8584c. ros2 service type svcname lists service types that are registered on the ROS 2 network for the provided svcname. By clicking Sign up for GitHub, you agree to our terms of service and I'm having a similar issue. Topics allow for a many-to-many relationship: multiple nodes can listen on the same topic, and each node can publish data on multiple topics. to your account. There are a few different things going on here. You can use the python client library and ask for the topics for each node: using get_publisher_names_and_types_by_node iterating through each node on the system which is available via get_node_names Both are documented in the rclpy Node API: http://docs.ros2.org/latest/api/rclpy. After that you can get a correct result on "ros2 topic list command". I had same problem before. There are a few different things going on here. ROS2 Fastdds Discovery no topics listed ros2 foxy discovery fastdds dds demo_nodes_cpp talker listener rqt command_line_tool ROS_DISCOVERY_SERVER asked Mar 2 '21 highmax1234 98 7 14 14 Hello, I followed this tutorial to set up a discovery server for ros2. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. So in that sense, you are in new (and unsupported) territory. You should see the (x, y) coordinates of the object (in the camera reference frame) printed to the screen. The text was updated successfully, but these errors were encountered: We don't officially support macOS Catalina on any released ROS 2 distribution. Since 0.9.2-1focal.20210217.003839 And now, on an another terminal, if you run rostopic list you will be able to see the topic /chatter. Already on GitHub? This version uses the topic of the different nodes to decide if two nodes must be connected, or they could be left unmatched. Define custom messages in python package (ROS2). All the parameters used for overriding QoS could be declared as hidden, thus avoiding "noise" in commands like ros2 param list. The method to use is get_topic_names_and_types. However, do take into account this comment: https://github.com/ros2/ros2/issues/1. ros2 topic list -t. To listen to any topic, type: ros2 topic echo /topic_name. same problem with ros2 foxy, did you find a solution? The method to use is get_topic_names_and_types. So if you use the method right at startup you may not get the full results. So, this is really great. How to list the ros2 topics from a c++ node? I had the same problem, but ros2 daemon stop and ros2 daemon start did not help. Please start posting anonymously - your entry will be published after you log in or create a new account. Creative Commons Attribution Share Alike 3.0. Instead the message 608065823.126248 [0] ros2: using network interface enp5s0 (udp/192.168.0.85) selected arbitrarily from: enp5s0, virbr0, tun0, br-92101ca58b28, docker0 is shown. A simple publisher. 1 comment Contributor sloretz commented 15 days ago Bug report Required Info: Operating System: Windows 10 Installation type: binaries Version or commit hash: Please start posting anonymously - your entry will be published after you log in or create a new account. Well occasionally send you account related emails. Marked as correct! Something equivalent to the commnand line ros2 topic list. ros2 topic list - Find all Topics on your graph You can find the list of all topics that some nodes are publishing or subscribing to. but it looks like only shows the topics associated to the current node. The length of the DDS topic must not exceed 256 characters. However, when I kill the '_ros2_daemon', and then run the ros2 topic list (or node list) command again, it works again, but only for that one time again. privacy statement. Therefore the length of a ROS Topic, including the namespace hierarchy, the base name of the topic and any ros specific prefixes must not exceed 256 characters since this is mapped directly as DDS topic. The text was updated successfully, but these errors were encountered: I cannot reproduce this issue on my environment. privacy statement. For convenience here is a summary of all rules for topic and service names in ROS 2: must not be empty may contain alphanumeric characters ( [0-9|a-z|A-Z] ), underscores ( _ ), or forward slashes ( /) ros2 topic list, ros2 msg list not working. For example: ros2 topic echo /pos_in_cam_frame. You signed in with another tab or window. Validated by installing ROS2 in a fresh Docker container from Dockerhub labeled as ubuntu:focal-20210119. With ROS2 Dashing installed. In the future, please open questions like this on https://answers.ros.org. I am a fan of Sherlock Holmes so I will use that as an example, especially the one filmed by BBC. I don't think you are actually using Crystal, but it is a bit confusing. Topics are a vital element of the ROS graph that act as a bus for nodes to exchange messages. ros2 topic list I get a correct result, showing the available topics that are being published. For the turtlesim robot, the command ros2 topic list returns the following topics: Have a question about this project? Well occasionally send you account related emails. I get a correct result, showing the available topics that are being published. could not find any instance of Visual Studio. In general, it can take some time for discovery to happen. micro_ros_setup No definition of [python3-vcstool] for OS [osx], ROS2 topic list only working once (or any other command), Creative Commons Attribution Share Alike 3.0. ade --rc AutowareAuto/.aderc-lgsvl start --update --enter, INFO: Using non-default AutowareAuto/.aderc-lgsvl configuration file, master: Pulling from autowarefoundation/autoware.auto/autowareauto/amd64/ade-dashing, Digest: sha256:49e791b3b3e34f295ee38019c02fc4df32bbd960e7e7b504bc61914b7989874f, Status: Image is up to date for registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/ade-dashing:master, registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/ade-dashing:master, master: Pulling from autowarefoundation/autoware.auto/autowareauto/amd64/binary-dashing, Digest: sha256:317d716d52165e8d8de6e337413ebc808a4eabcae84866b4eabab6d32e29fbf6, Status: Image is up to date for registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/binary-dashing:master, registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/binary-dashing:master, 2020.08-native-bridge: Pulling from apexai/ade-lgsvl, Digest: sha256:980c2c16f9017b8f79f49124d376be74a9f66d8e729889c3325535a0a6e9bb31, Status: Image is up to date for registry.gitlab.com/apexai/ade-lgsvl:2020.08-native-bridge, registry.gitlab.com/apexai/ade-lgsvl:2020.08-native-bridge, ade-dashing | 7c7a94a34aa2 | master | registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/ade-dashing:master, binary-dashing | 5c11d640a49f | master | registry.gitlab.com/autowarefoundation/autoware.auto/autowareauto/amd64/binary-dashing:master, ade-lgsvl | 2020.08-native-bridge | 2020.08-native-bridge | registry.gitlab.com/apexai/ade-lgsvl:2020.08-native-bridge, ade_registry.gitlab.com_autowarefoundation_autoware.auto_autowareauto_amd64_binary-dashing_master, ade_registry.gitlab.com_apexai_ade-lgsvl_2020.08-native-bridge, non-network local connections being added to access control list, Current default time zone: 'Europe/Moscow'. With ROS2 bags, you can run your robot, record a sample (bag) of what's happening, and then use this sample again and again. everything hangs). The command-line tool then queries the daemon for information. That may also be what happened for you with get_node_names. Ubuntu 20.04 (focal-20210119). When you launch any ros2 command-line tool the first time, a daemon is spun up in the background. I am interested in all the topics in the ros2 network. However, when I run this command a second time, it only shows the default topics: Any consecutive command after the first one will give this default result. $ ros2 topic list /greetings /parameter_events /rosout As you can see here, we have 3 topics: /greetings: the one we've just created with a publisher. Now, if you get the list of all topics running in your graph with ros2 topic list: $ ros2 topic list /data_1 /data_2 /data_3 /parameter_events /rosout. Next run Cargo run and checkout the topics via ros2 topic list , output is /hw_topic /parameter_events /rosout. The pathnames in your output above all have the word "crystal" in it. You can get more information about these Topics with the following command: Opening issue in ros2cli project. Where you replace "/topic_name" with the name of the topic. However, when it came to ros2 topic list Thank you, sounds good, I am going to check that and I will return with the result! The following command (again in a new terminal) will show you a list of the Topics that are either being published or subscribed to by a node: $ ros2 topic list The output in your terminal should look like this: Now, you know which topics are currently available. If you can't see it, then there is a problem. I don't think you are actually using Crystal, but it is a bit confusing. That is what ros2 topic list uses, as well as for instance what the RQT topic plugin uses to list the available topics. By clicking Sign up for GitHub, you agree to our terms of service and ros2 topic list hangs ade with some odd log message I'm using the latest master branch 5c11d640a49f1a1caa0de8add4e4c782d3a8584c While in ADE_HOME start it with ade --rc AutowareAuto/.aderc-lgsvl start --update --enter Source the setup.bash from /opt/AutowareAuto/setup.bash Run ros2 topic list OBSERVED: No topics are listed. Also, you can play back a ROS2 bag so you can skip starting some parts of your robot application. OBSERVED: No topics are listed. You signed in with another tab or window. Have a question about this project? So that is expected not to work anymore. To check the data, use ros2 topic echo /hw_topic. $ ros2 daemon start That is what ros2 topic list uses, as well as for instance what the RQT topic plugin uses to list the available topics. In Foxy, we have completely removed the ros2 msg command, and it has been replaced by ros2 interface. The daemon then does discovery, and hangs around. I'm going to close this out. Also guys do not forget to spin the node! ros2 service list lists service names that are registered on the ROS 2 network through either servers or clients. Sign in That way we can have all of the questions and answers in one searchable place. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. However, when I run this command a second time, it only shows the default topics: /parameter_events /rosout Any consecutive command after the first one will give this default result. Universal Time is now: Tue Dec 15 20:56:42 UTC 2020. alexey@ade:~$ source /opt/AutowareAuto/setup.bash, 1608065823.126248 [0] ros2: using network interface enp5s0 (udp/192.168.0.85) selected arbitrarily from: enp5s0, virbr0, tun0, br-92101ca58b28, docker0. ROS Topic and Service Name Length Limit. Discovery Server v2. The talker and listener examples all worked fine. 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