[ros2action] Display info about action goals on an action server

[jacobperron]

Feature request

Feature description

Proposed originally in #202.

Add a goal verb for getting info about active or terminated goals for a given action server.

Proposed usage:

• List goals for a given action name. Output node names with action servers and goal IDs.

ros2 action goal list [--count] ACTION_NAME

E.g.

$ ros2 action goal list /fibonacci
/node/foo: 2
    152790028afb49a3b3c61383e6b97320
    8c3449e71c9941ed8ad3d68fdd7f553c
/another/node/bar: 1
    b07cb18ca2dc4cca95acfc131fc49223

$ ros2 action goal list --count /fibonacci
/node/foo: 2
/another/node/bar: 1

• Get details for a specific goal (request, result, status).

ros2 action goal info [--goal-only] [--status-only] [--result-only] ACTION_NAME GOAL_UUID

$ ros2 action goal info /fibonacci 152790028afb49a3b3c61383e6b97320
Goal:
  order: 5

Status: EXECUTING

$ ros2 action goal info /fibonacci 8c3449e71c9941ed8ad3d68fdd7f553c
Goal:
  order: 5

Status: SUCCEEDED

Result:
  sequence: [0, 1, 1, 2, 3]

Implementation considerations

I believe most of the proposed API should be feasible, except for accessing the goal request arguments, which requires adding some new API for getting this information to the rcl level.

[jacobperron]

Alternatively, it has been proposed to instead merge this feature with the info verb.

E.g

$ ros2 action info --goal-request-only /fibonacci
/node/foo: 2
  152790028afb49a3b3c61383e6b97320
    order: 10
  8c3449e71c9941ed8ad3d68fdd7f553c
    order: 1
/another/node/bar: 1
  b07cb18ca2dc4cca95acfc131fc49223
    order: 5

[ste93]

Has anyone got any news from this?

[clalancette]

We're not currently working on this feature, but we are happy to review pull requests that implement it.