我写了一个Python脚本,检查一个特定的电子邮件地址,并将新的电子邮件传递给一个外部程序。如何让这个脚本全天候执行,比如在Linux中将其转换为守护进程或服务。我是否还需要一个在程序中永不结束的循环,或者可以通过多次重新执行代码来完成?
当前回答
Ubuntu有一个非常简单的方法来管理服务。 对于python来说,不同之处在于所有依赖项(包)都必须在运行主文件的同一目录中。
我只是设法创建了这样一个服务,为我的客户提供天气信息。 步骤:
Create your python application project as you normally do. Install all dependencies locally like: sudo pip3 install package_name -t . Create your command line variables and handle them in code (if you need any) Create the service file. Something (minimalist) like: [Unit] Description=1Droid Weather meddleware provider [Service] Restart=always User=root WorkingDirectory=/home/ubuntu/weather ExecStart=/usr/bin/python3 /home/ubuntu/weather/main.py httpport=9570 provider=OWMap [Install] WantedBy=multi-user.target Save the file as myweather.service (for example) Make sure that your app runs if started in the current directory python3 main.py httpport=9570 provider=OWMap The service file produced above and named myweather.service (important to have the extension .service) will be treated by the system as the name of your service. That is the name that you will use to interact with your service. Copy the service file: sudo cp myweather.service /lib/systemd/system/myweather.service Refresh demon registry: sudo systemctl daemon-reload Stop the service (if it was running) sudo service myweather stop Start the service: sudo service myweather start Check the status (log file with where your print statements go): tail -f /var/log/syslog Or check the status with: sudo service myweather status Back to the start with another iteration if needed
此服务现在正在运行,即使您退出也不会受到影响。 如果主机关闭并重新启动,则此服务将重新启动…
其他回答
要创建一些像service一样运行的东西,你可以使用这个东西:
你必须做的第一件事是安装水泥框架: 水泥框架是一个CLI框架,您可以在其上部署应用程序。
app命令行界面:
interface.py
from cement.core.foundation import CementApp
from cement.core.controller import CementBaseController, expose
from YourApp import yourApp
class Meta:
label = 'base'
description = "your application description"
arguments = [
(['-r' , '--run'],
dict(action='store_true', help='Run your application')),
(['-v', '--version'],
dict(action='version', version="Your app version")),
]
(['-s', '--stop'],
dict(action='store_true', help="Stop your application")),
]
@expose(hide=True)
def default(self):
if self.app.pargs.run:
#Start to running the your app from there !
YourApp.yourApp()
if self.app.pargs.stop:
#Stop your application
YourApp.yourApp.stop()
class App(CementApp):
class Meta:
label = 'Uptime'
base_controller = 'base'
handlers = [MyBaseController]
with App() as app:
app.run()
YourApp.py类:
import threading
class yourApp:
def __init__:
self.loger = log_exception.exception_loger()
thread = threading.Thread(target=self.start, args=())
thread.daemon = True
thread.start()
def start(self):
#Do every thing you want
pass
def stop(self):
#Do some things to stop your application
请记住,你的应用程序必须运行在一个线程作为守护进程
要运行应用程序,只需在命令行中这样做
Python interface.py——help
cron is clearly a great choice for many purposes. However it doesn't create a service or daemon as you requested in the OP. cron just runs jobs periodically (meaning the job starts and stops), and no more often than once / minute. There are issues with cron -- for example, if a prior instance of your script is still running the next time the cron schedule comes around and launches a new instance, is that OK? cron doesn't handle dependencies; it just tries to start a job when the schedule says to.
如果您发现确实需要一个守护进程(一个永不停止运行的进程),请查看一下监控器。它提供了一种简单的方法来包装普通的、非守护进程化的脚本或程序,并使其像守护进程一样运行。这比创建本地Python守护进程好得多。
假设您真的希望您的循环作为后台服务全天候运行
对于一个不需要向代码中注入库的解决方案,你可以简单地创建一个服务模板,因为你使用的是linux:
[Unit]
Description = <Your service description here>
After = network.target # Assuming you want to start after network interfaces are made available
[Service]
Type = simple
ExecStart = python <Path of the script you want to run>
User = # User to run the script as
Group = # Group to run the script as
Restart = on-failure # Restart when there are errors
SyslogIdentifier = <Name of logs for the service>
RestartSec = 5
TimeoutStartSec = infinity
[Install]
WantedBy = multi-user.target # Make it accessible to other users
将该文件放在您的守护进程服务文件夹(通常是/etc/systemd/system/)中,*. .使用以下systemctl命令安装它(可能需要sudo权限):
systemctl enable <service file name without .service extension>
systemctl daemon-reload
systemctl start <service file name without .service extension>
然后你可以使用命令检查你的服务是否在运行:
systemctl | grep running
这是一个很好的类,从这里采取:
#!/usr/bin/env python
import sys, os, time, atexit
from signal import SIGTERM
class Daemon:
"""
A generic daemon class.
Usage: subclass the Daemon class and override the run() method
"""
def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
self.stdin = stdin
self.stdout = stdout
self.stderr = stderr
self.pidfile = pidfile
def daemonize(self):
"""
do the UNIX double-fork magic, see Stevens' "Advanced
Programming in the UNIX Environment" for details (ISBN 0201563177)
http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
"""
try:
pid = os.fork()
if pid > 0:
# exit first parent
sys.exit(0)
except OSError, e:
sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
sys.exit(1)
# decouple from parent environment
os.chdir("/")
os.setsid()
os.umask(0)
# do second fork
try:
pid = os.fork()
if pid > 0:
# exit from second parent
sys.exit(0)
except OSError, e:
sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
sys.exit(1)
# redirect standard file descriptors
sys.stdout.flush()
sys.stderr.flush()
si = file(self.stdin, 'r')
so = file(self.stdout, 'a+')
se = file(self.stderr, 'a+', 0)
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
# write pidfile
atexit.register(self.delpid)
pid = str(os.getpid())
file(self.pidfile,'w+').write("%s\n" % pid)
def delpid(self):
os.remove(self.pidfile)
def start(self):
"""
Start the daemon
"""
# Check for a pidfile to see if the daemon already runs
try:
pf = file(self.pidfile,'r')
pid = int(pf.read().strip())
pf.close()
except IOError:
pid = None
if pid:
message = "pidfile %s already exist. Daemon already running?\n"
sys.stderr.write(message % self.pidfile)
sys.exit(1)
# Start the daemon
self.daemonize()
self.run()
def stop(self):
"""
Stop the daemon
"""
# Get the pid from the pidfile
try:
pf = file(self.pidfile,'r')
pid = int(pf.read().strip())
pf.close()
except IOError:
pid = None
if not pid:
message = "pidfile %s does not exist. Daemon not running?\n"
sys.stderr.write(message % self.pidfile)
return # not an error in a restart
# Try killing the daemon process
try:
while 1:
os.kill(pid, SIGTERM)
time.sleep(0.1)
except OSError, err:
err = str(err)
if err.find("No such process") > 0:
if os.path.exists(self.pidfile):
os.remove(self.pidfile)
else:
print str(err)
sys.exit(1)
def restart(self):
"""
Restart the daemon
"""
self.stop()
self.start()
def run(self):
"""
You should override this method when you subclass Daemon. It will be called after the process has been
daemonized by start() or restart().
"""
你可以使用fork()将你的脚本从tty中分离出来,并让它继续运行,如下所示:
import os, sys
fpid = os.fork()
if fpid!=0:
# Running as daemon now. PID is fpid
sys.exit(0)
当然你还需要实现一个无限循环,比如
while 1:
do_your_check()
sleep(5)
希望这能让你开始。
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