ros1_srv

srv 그림

 

https://docs.ros.org/en/dashing/Tutorials/Services/Understanding-ROS2-Services.html

Understanding ROS 2 services — ROS 2 Documentation: Dashing documentation

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msg = noneblock 개념 = 1 : 다

srv = block 개념 = 1 : 1 =

action = block + noneblock 개념

 

사용할 srv data type

 

 

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add_two_ints_server.py

#서버
#!/usr/bin/env python3

# import the AddTwoInts service
from rospy_tutorials.srv import *
import rospy

def add_two_ints(req):
    print("Returning [%s + %s = %s]" % (req.a, req.b, (req.a + req.b)))
    return AddTwoIntsResponse(req.a + req.b)

def add_two_ints_server():
    rospy.init_node('add_two_ints_server')
    s = rospy.Service('add_two_ints', AddTwoInts, add_two_ints)

    # spin() keeps Python from exiting until node is shutdown
    rospy.spin()

if __name__ == "__main__":
    add_two_ints_server()

 

 

 

add_two_ints_client.py

#클라이언트
#!/usr/bin/env python3

import sys
import os

import rospy

# imports the AddTwoInts service
from rospy_tutorials.srv import *

## add two numbers using the add_two_ints service
## @param x int: first number to add
## @param y int: second number to add
def add_two_ints_client(x, y):

    # NOTE: you don't have to call rospy.init_node() to make calls against
    # a service. This is because service clients do not have to be
    # nodes.

    # block until the add_two_ints service is available
    # you can optionally specify a timeout
    rospy.wait_for_service('add_two_ints')

    try:
        # create a handle to the add_two_ints service
        add_two_ints = rospy.ServiceProxy('add_two_ints', AddTwoInts)

        print("Requesting %s+%s"%(x, y))

        # simplified style
        resp1 = add_two_ints(x, y)

        # formal style
        resp2 = add_two_ints.call(AddTwoIntsRequest(x, y))

        if not resp1.sum == (x + y):
            raise Exception("test failure, returned sum was %s"%resp1.sum)
        if not resp2.sum == (x + y):
            raise Exception("test failure, returned sum was %s"%resp2.sum)
        return resp1.sum
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def usage():
    return "%s [x y]"%sys.argv[0]

if __name__ == "__main__":

    argv = rospy.myargv()
    if len(argv) == 1:
        import random
        x = random.randint(-50000, 50000)
        y = random.randint(-50000, 50000)
    elif len(argv) == 3:
        try:
            x = int(argv[1])
            y = int(argv[2])
        except:
            print(usage())
            sys.exit(1)
    else:
        print(usage())
        sys.exit(1)
    print("%s + %s = %s"%(x, y, add_two_ints_client(x, y)))

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서비스랑 클라이언트도 딱 3개임 ( srv명의 request와 response 데이터타입에 맞춰서 날려줘야함 )

connect , request , response

1. server가 특정 네임스페이스+ 특정 srv로 서비스 등록

2. client 가 server에 request

3. server가 response

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keyword :

init_node

Service

wait_for_service

ServiceProxy

네임스페이스.call(srv명Request(x, y))

srv명Response(req.a + req.b) 

 

---

connect : rospy.Service('add_two_ints', AddTwoInts, add_two_ints),

rospy.wait_for_service(네임스페이스) , rospy.ServiceProxy(네임스페이스,srv명)

 

request : 네임스페이스.call(srv명Request(x, y))

 

response : srv명Response(req.a + req.b)