Solution: ROS Services vs ROS Actions

Both ROS Services and Actions provide communication between ROS nodes, but they are designed for different kinds of tasks.

Feature	ROS Service	ROS Action
Communication	Request-response	Goal-feedback-result
Task type	Short operations	Long-running operations
Feedback	Normally no continuous feedback	Provides continuous feedback
Cancellation	Not designed for cancellation	Goal can be cancelled/preempted
Result	Returned after request	Final result returned separately
Example	Reset a sensor	Navigate to a destination

ROS Service

A service is synchronous request-response communication.

Client → Request → Service Server
Client ← Response ← Service Server

Examples include resetting a controller, requesting a calculation or changing a configuration parameter.

ROS Action

An action is intended for operations that may take significant time.

Client → Goal → Action Server
Client ← Feedback ← Action Server
Client ← Result ← Action Server
        ↑
      Cancel

For example, autonomous navigation may take several seconds or minutes. The client can receive distance/progress feedback and cancel the goal if necessary.

Conclusion

Use a Service for short request-response operations and an Action for long-running, feedback-producing and cancellable tasks.