ms-iot
[rosserial_server] Unable to look up message: Unable to import message module
When using rosserial_server on a ROS node, the following error messages show up:
[ WARN] [1596233541.330902100]: Unable to look up message: Unable to import message module xxx_msgs.
[ WARN] [1596233541.331036100]: Advertising on topic [/xxx] with an empty message definition. Some tools (e.g. rosbag) may not work correctly.
One possible reason to this failure is that one of the dependency PyYaml cannot incorporate well in the Python\C embedded environment, and for more details. Please see https://github.com/yaml/pyyaml/issues/423.
And as a workaround, you may check the version of PyYaml in your system and use pip install -U --force pyyaml==3.12 to downgrade to the last known good build.
@seanyen , i installed pyyaml=5.3.1, rosserial_server can work. So i don't think the issue is caused by this package.
@xuliujian Thanks for sharing your data. Do you mind sharing more about your environment? (Such as, what's the ROS distro, Python version, etc?)