roseus: add :last-status-msg method for simple-action-client

[furushchev]

Adds :last-status-msg method to simple-action-client class.
One use case is to check if the action server is processing any goals from any clients.
In rospy, the message can be used in a similar way.

ac = actionlib.SimpleActionClient(...)
status = ac.action_client.last_status_msg

[furushchev]

-------------------------------------------------

<?xml version="1.0" encoding="utf-8"?>

<testsuite errors="0" failures="1" name="unittest.suite.TestSuite" tests="1" time="5.194">

  <testcase classname="__main__.HzTest" name="test_hz" time="5.1938">

    <failure type="AssertionError">average rate (10.618Hz) exceeded maximum (10.500Hz)

  File "/usr/lib/python2.7/unittest/case.py", line 331, in run

    testMethod()

  File "/opt/ros/indigo/share/rostest/nodes/hztest/hztest", line 117, in test_hz

    self._test_hz(hz, hzerror, topic, test_duration, wait_time)

  File "/opt/ros/indigo/share/rostest/nodes/hztest/hztest", line 190, in _test_hz

    (rate, self.max_rate))

  File "/usr/lib/python2.7/unittest/case.py", line 424, in assertTrue

    raise self.failureException(msg)

    </failure>

  </testcase>

  <system-out><![CDATA[Hz: 10.0

Hz Error: 0.5

Topic: chatter1

Test Duration: 5.0

Waiting for messages

Starting rate measurement

Done waiting, validating results

]]></system-out>

  <system-err><![CDATA[]]></system-err>

</testsuite>

unrelated error occured. Restarted.

[k-okada]

is this different from (send comm-state :latest-goal-status)? And how roscpp users work with this?
https://docs.ros.org/indigo/api/actionlib/html/classactionlib_1_1SimpleActionClient.html

[furushchev]

(send comm-state :latest-goal-status) returns only the status (type of actionlib_msgs/GoalStatus) which is related to the client selected from all the status list.
Furthermore, it returns a dummy message unless at least one goal is sent from the client.
(send client :last-status-msg) returns all status (type of actionlib_msgs/GoalStatusArray).

Since I want to check the action server is used by other clients or not, (send comm-state :latest-goal-status) does not have information about other clients.

As far as I briefly search In roscpp, SimpleActionClient has no such api, but I think we can get the same status message (actionlib_msgs/GoalStatusArray) by just subscribing status twice.
(If I understand correctly, we cannot register more than two functions for the same topic in roseus for now.)