在 Raspberry pi 上的 python3 中启动和停止 systemd 服务

Question

我正在尝试使用一个按钮来查找服务，如果服务正在运行，然后调用 systemctl stop“service”，如果它没有运行，则调用 systemctl start“service”

这是我正在使用的代码：

import  RPi.GPIO as GPIO
import time
import os
import subprocess


GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)


service_name = "record"

def minitor(channel):
    try:

        output = subprocess.run(["systemctl", "status", service_name], capture_output=True)
        status = output.stdout.decode().strip()
        if "inactive" in status:
            subprocess.run(["systemctl", "start", service_name])
            print(f"{service_name} service has been started")
            time.sleep(1)
        elif "Active" in status:
            print(f"{service_name} service is Active so stopping it now")
            subprocess.run(["systemctl", "stop", service_name])

    except OSError as ose:
        print("Error while trying to do something with the service", ose)

    pass


while True:
    try:
        GPIO.setwarnings(False)
        GPIO.setmode(GPIO.BOARD)
        GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
        GPIO.add_event_detect(22,GPIO.RISING,callback=minitor)
        time.sleep(10)
    finally:
        GPIO.cleanup()

message = input("Press enter to quit\n\n")
GPIO.cleanup() # Clean up

不幸的是，只有第一次推送似乎有效，然后循环就开始工作，因此服务启动然后停止并启动...停止...

Answer 1

添加了上面的建议： 这是下面的脚本，不幸的是 if 和 elif 的条件似乎仍在循环中。

这是我按下按钮一次时发生的情况：

Ready
inactive
record service has been started
active
record service is Active so stopping it now
Ready

_____下面的脚本

import  RPi.GPIO as GPIO
import time
import os
import subprocess


GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)


service_name = "record"
service_inactive = "inactive"
service_active = "active"
def minitor(channel):
    try:

        output = subprocess.run(["systemctl", "is-active", service_name], capture_output=True)
        status = output.stdout.decode().strip()
        if service_inactive in status:
            print(status)
            subprocess.run(["systemctl", "start", service_name])
            print(f"{service_name} service has been started")
            status = "active"
            
        elif service_active in status:
            print(status)
            print(f"{service_name} service is Active so stopping it now")
            subprocess.run(["systemctl", "stop", service_name])
            status = "inactive"
    except OSError as ose:
        print("Error while trying to do something with the service", ose)

    pass


while True:
    try:
        print("Ready")
        GPIO.setwarnings(False)
        GPIO.setmode(GPIO.BOARD)
        GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

        GPIO.add_event_detect(22,GPIO.RISING,callback=minitor)
        time.sleep(10)
    finally:
        GPIO.cleanup()

message = input("Press enter to quit\n\n")
GPIO.cleanup() # Clean up