How can I check if a service exists from Python?

Question

This question has an answer for roscpp; what is the equivalent solution for Python?

EDIT: I do not want to wait for the service. I want to take one action if the service exists and a different action if it doesn't exist.

A hack might be to wrap a wait_for_service call in a try/catch to catch a ROSException and verify that that ROSException was a timeout, but that's very ugly and I'm not sure what the minimum required timeout should be to ensure that extant topics do not cause the Exception.

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Originally posted by BJP on ROS Answers with karma: 100 on 2017-06-01

Post score: 1

Answer 1

There is a function in the rospy API to get a list of services: http://docs.ros.org/kinetic/api/rospy/html/rospy.service.ServiceManager-class.html#get_services

I guess this would return a list of all registered services and you could check if the service you are waiting for is in this list.

Edit: I haven't tested the API call I linked in the original answer. I used http://docs.ros.org/kinetic/api/rospy/html/rospy.service.ServiceManager-class.html#get_services

It works for me:

>>> import rosservice
>>> service_list = rosservice.get_service_list()
>>> print service_list
['/rosout/set_logger_level', '/rosout/get_loggers']

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Originally posted by Zubin Priyansh with karma: 161 on 2017-06-02

This answer was ACCEPTED on the original site

Post score: 3

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Original comments

Comment by NEngelhard on 2017-06-03:
Have you tried this?

Comment by Zubin Priyansh on 2017-06-03:
@NEngelhard I had successfully gotten a list of services in rospy, but now I realize it wasn't with this particular API call. I used this call: http://docs.ros.org/kinetic/api/rosservice/html/rosservice-pysrc.html#get_service_list . I should edit my answer accordingly.