[TASK] Operation Mode msg + srv

[jorgenfj]

Description of task

We should define a custom message that encodes the operation modes, instead of having these be sent as raw strings. With the inclusion of an Operation mode manager an operation mode service should also be created to enable clients to request an operation mode change.

Suggested Workflow

No response

Specifications

• Operation mode message with relevant modes defines as constants/enum types. These constants/enums should be referenced in code when using these messages for increased code clarity.
• Operation mode service should support requests for setting operation mode, should handle or invalid requests. Should also return resulting operation mode after service call is perform, regardless of service success or failure.

Contacts

No response

Code Quality

• Every function in header files are documented (inputs/returns/exceptions)
• The project has automated tests that cover MOST of the functions and branches in functions (pytest/gtest)
• The code is documented on the wiki (provide link)

[eirisak]

The current operation mode topic only has "Autonomous mode" or not "Autonomous mode" whereas "XBOX" and reference is defined within joystick interface and is only handled by joystick interface. Killswitch is its own topic which is either on or off. Should I make the custom message be categorized as either Autonomous, Reference, Xbox or killswitch, or do I make it similar in setup to the current version?

[jorgenfj]

I think we should aim to keep a similar structure as we already have. Xbox and Reference mode is something the controllers should not be aware of, they only care about whether we are in autonomous mode or not. This can be achieved by defining constants for all modes in the message type, but having these be internal to the joystick node.
Operation mode manager should still handle the service requests that the joystick node makes to switch modes, the resulting mode can sent as the result of the service back to the joystick node, whether we are in xbox or reference etc.. If the joystick requested a change into xbox or reference mode the operation mode manager should still publish the current mode, but then only differentiate between autonomous or xbox.

This is an example of how you can access the constants defined for the different modes in code.

from my_robot_msgs.msg import OperationMode

def callback(msg: OperationMode):
    if msg.mode == OperationMode.AUTONOMOUS:
        print("Robot is in autonomous mode!")
    else:
        print("Robot is in another mode.")

We could also prepend the name identifier for xbox and reference mode to JOY_XBOX and JOY_REFERENCE to emphasize that these are used internally in the joystick interface node.

[jorgenfj]

I also believe that killswitch should remain a separate topic since this is not technically an operation mode, but a safety feature. Killswitch should still be managed by the operation mode manager the same way operation mode is.