# Gazebo unresponsive to service call **URL:** \ **Category:** ROS Beginners Exam\ **Created:** [April 15, 2021, 7:43pm UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458 "2021-04-15T19:43:27Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![torpanvil](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/t/eada6e/32.png) [@torpanvil](https://get-help.theconstruct.ai/u/torpanvil)\ **Post date:** [April 15, 2021, 7:43pm UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/1 "2021-04-15T19:43:27Z")
Hello, I’m having an issue with task 2. I’ve got the drone moving, landing and taking off, and launch file works fine too. However, when calling the service /my\_service through the command line, the method take\_off() is called, but gazebo does not react. Is this an error in gazebo, or my coding? Thank you. forward\_motion.py ``` #! /usr/bin/env python import rospy import time from geometry_msgs.msg import Twist from std_msgs.msg import Empty class RobotControl(object): def __init__ (self): # creates publishers self.pub_cmd_vel = rospy.Publisher("/cmd_vel", Twist, queue_size=10) self.pub_take_off = rospy.Publisher("/drone/takeoff", Empty, queue_size=10) self.pub_land = rospy.Publisher("/drone/land", Empty, queue_size=10) # creates messages to publish self.move = Twist() self.takeoff = Empty() self.land = Empty() self.rate = rospy.Rate(10) def take_off(self): rospy.loginfo('Taking off...') self.pub_take_off.publish(self.takeoff) time.sleep(5) rospy.loginfo("The quadcopter finished taking off") def move_forward(self): rospy.loginfo("Moving forward...") self.move.linear.x = 1 self.move.angular.z = 0 self.pub_cmd_vel.publish(self.move) time.sleep(5) rospy.loginfo("The quadcopter finished moving forward") def stopping(self): rospy.loginfo('Stopping...') self.move.linear.x = 0 self.move.angular.z = 0 self.pub_cmd_vel.publish(self.move) time.sleep(5) rospy.loginfo("The quadcopter finished stopping") def landing(self): rospy.loginfo('Landing...') self.pub_land.publish(self.land) time.sleep(5) rospy.loginfo("The quadcopter finished landing") if __name__ == ' __main__': name_of_node = "forward_motion" rospy.init_node(name_of_node) rospy.loginfo("Node initiated: %s", name_of_node) rc = RobotControl() time.sleep(2) rate = rospy.Rate(0.5) ctrl_c = False def shutdownhook(): global ctrl_c rospy.loginfo("Shutdown time!") ctrl_c = True rospy.on_shutdown(shutdownhook) while not ctrl_c: # while not true rospy.loginfo("Main loop...") rc.take_off() rc.move_forward() rc.stopping() rc.landing() ctrl_c = True ``` motion\_service.py ``` #! /usr/bin/env python import rospy from std_srvs.srv import EmptyResponse, Empty as EmptyServiceMsg from std_msgs.msg import Empty from forward_motion import RobotControl def my_callback(request): rospy.loginfo("The Service to start the drone has been called") rc = RobotControl() rc.take_off() rospy.loginfo("Finished service") response = EmptyResponse() return response rospy.init_node('service_move_drone') my_service = rospy.Service('/my_service', EmptyServiceMsg , my_callback) rospy.loginfo("Service /my_service Ready") rospy.spin() # mantain the service open. ``` ---
**Author:** ![u1802520](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/u1802520/32/6826_2.png) [@u1802520](https://get-help.theconstruct.ai/u/u1802520)\ **Post date:** [April 15, 2021, 9:24pm UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/2 "2021-04-15T21:24:06Z")
Try looping the command: > for i in range(10): > self.pub\_take\_off.publish(self.takeoff) publishing in topics sometimes fails the first time you publish. ---
**Author:** ![torpanvil](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/t/eada6e/32.png) [@torpanvil](https://get-help.theconstruct.ai/u/torpanvil)\ **Post date:** [April 16, 2021, 8:25am UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/3 "2021-04-16T08:25:15Z")
Great. Thanks! It worked. Say you have several topics in a program, how would one go about writing a function/method to publish once into all topics, without actually causing the robot to act on it? Would it make sense to put such a function as the first call in the program once everything is set up, or should it be called EVERY time a publish is wanted? ---
**Author:** ![bayodesegun](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/bayodesegun/32/10684_2.png) [@bayodesegun](https://get-help.theconstruct.ai/u/bayodesegun)\ **Post date:** [April 16, 2021, 9:02am UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/4 "2021-04-16T09:02:10Z")
A post was split to a new topic: [How to get all topics ready for publishing](https://get-help.theconstruct.ai/t/how-to-get-all-topics-ready-for-publishing/9463) ---
**Author:** ![bayodesegun](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/bayodesegun/32/10684_2.png) [@bayodesegun](https://get-help.theconstruct.ai/u/bayodesegun)\ **Post date:** [April 16, 2021, 8:52am UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/5 "2021-04-16T08:52:43Z")
@torpanvil. Bravo!!! This is a great way to do it, and I’m going to make this a wiki for everyone! ---
**Author:** ![torpanvil](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/t/eada6e/32.png) [@torpanvil](https://get-help.theconstruct.ai/u/torpanvil)\ **Post date:** [April 16, 2021, 9:00am UTC](https://get-help.theconstruct.ai/t/gazebo-unresponsive-to-service-call/9458/6 "2021-04-16T09:00:01Z")
Oh great! I must be getting better at this! 😅