Am I making the synchronous request correctly?

[bayodesegun]

@johnatabrayan

Why?

Threads are tricky, and the sync call should run in its own thread in order not to block the main thread.

@johnatabrayan

The way I understand synchronous requests, when the program gets to the line self.send_request() the thread stops and only continues when the request is done. But When I use only one thread the thread stops and never continues, even after the request is done. The program gets blocked at the end of the request and never executes line self.state = "FOLLOW_WALL"

You just described the way ROS 1 services work. You don’t even need to call them in a separate thread, but ROS 2 sync service calls seem to be much more complicated. Async calls are much easier to work with as @AshK mentioned.

You must have been asked to do this as a sync call in order to learn a bit about how that works, and it’s good you now know how to make it work. Good job!