ImportError: cannot import name 'MyCustomServiceMessage' from 'my_custom_srv_msg_pkg' exercise 6.3

Course Support ROS Basics In 5 Days (Python)
1

Hi, I have questions regarding exercise 6.3,

I’ve been dealing with this for hours but I couldn’t solve it.

the code is below
bb8_move_custom_service_server.py

#! /usr/bin/env python
import rospkg
import rospy
from my_custom_srv_msg_pkg import MyCustomServiceMessage, MyCustomServiceMessageResponse
from geometry_msgs.msg import Twist

def my_callback(request):
   rospy.loginfo("The Service move_bb8_in_circle_custom has been called")
   move_circle.linear.x = 0.2
   move_circle.angular.z = 0.2
   i = 0
   while i <= request.duration: 
       my_pub.publish(move_circle)
       rate.sleep()
       i=i+1
       
   move_circle.linear.x = 0
   move_circle.angular.z = 0
   my_pub.publish(move_circle)
   rospy.loginfo("Finished service move_bb8_in_circle_custom")
   
   response = MyCustomServiceMessageResponse()
   response.success = True
   return response # the service Response class, in this case EmptyResponse

rospy.init_node('service_move_bb8_in_circle_custom_server') 
my_service = rospy.Service('/move_bb8_in_circle_custom', MyCustomServiceMessage , my_callback) # create the Service called move_bb8_in_circle with the defined callback
my_pub = rospy.Publisher('/cmd_vel', Twist, queue_size=1)
move_circle = Twist()
rate = rospy.Rate(1)
rospy.loginfo("Service /move_bb8_in_circle_custom Ready")
rospy.spin() # mantain the service open.

launch file

<launch>

  <node pkg ="my_custom_srv_msg_pkg"
        type="bb8_move_custom_service_server.py"
        name="service_server"
        output="screen">
  </node>

</launch>

Cmakelist

cmake_minimum_required(VERSION 2.8.3)

project(my_custom_srv_msg_pkg)


find_package(catkin REQUIRED COMPONENTS

  std_msgs

  message_generation

)


add_service_files(

  FILES

  MyCustomServiceMessage.srv

)


generate_messages(

  DEPENDENCIES

  std_msgs

)


catkin_package(

  CATKIN_DEPENDS rospy

)

include_directories(

  ${catkin_INCLUDE_DIRS}

)

package.xml

<?xml version="1.0"?>

<package format="2">

  <name>my_custom_srv_msg_pkg</name>

  <version>0.0.0</version>

  <description>The my_custom_srv_msg_pkg package</description>

  <maintainer email="user@todo.todo">user</maintainer>

  <license>TODO</license>

  <buildtool_depend>catkin</buildtool_depend>

  <build_depend>rospy</build_depend>

  <build_depend>std_msgs</build_depend>

  <build_depend>message_generation</build_depend>

  <build_export_depend>rospy</build_export_depend>

  <exec_depend>rospy</exec_depend>

  <build_export_depend>std_msgs</build_export_depend>

  <exec_depend>std_msgs</exec_depend>

  <build_export_depend>message_runtime</build_export_depend>

  <exec_depend>message_runtime</exec_depend>

  <export>

  </export>

</package>

I already compile the package, delete “build” and “devel” folder and compile it again, but it seems when i tried to launch it, the results are always same.

image
image1356×221 17.2 KB

could someone please help? thanks in advanced

2

Did you run source devel/setup.bash after compiling. Please note that you need to run it on every terminal where you want to use the message, not just on the terminal where you compiled the package.

3

I already did it, but the results still same

4

I already solved it, my mistake I write the code crong, it should be :

from my_custom_srv_msg_pkg.srv
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