Using a ROS custom message type across machines/hosts

Question

I am unable to use a custom ROS message type on machine B that I have created on machine A.

Machine A:

• runs roscore.
• has the custom message code as a ROS package.
• has sourced the setup.bash of the package.
• runs rostopic pub /test_topic my_custom_msg test_value

Machine B:

• when I run: rostopic list, I do see the topic I am publishing to on machine A ("/test_topic").
• when I run: runmsg list, I DO NOT see the custom message type I am looking for (the one, my topic is using: "my_custom_msg")

When I do these things locally, means all on machine A, everything works as expected: I am publishing a test message using my custom message type and with rostopic echo I can even successfully subscribe to it with getting all the messages that are sent displayed correctly.

So, what am I missing in order to use my custom message from machine A also on machine B?

Please, I really need help on that!

Answer 1

I solved the problem!

The solution is to simply have the custom message definition on all machines where you'd want to use it.

This might be most comfortable if the custom message is realized as a separate ROS package, because then it's easier to distribute it among different machines.