Running python script in background
my script is a server that listens for client requests and sends responses. It handles requests by streaming:
class Server:
def __init__(self):
self.host = ''
self.port = 50000
self.backlog = 5
self.size = 1024
self.server = None
self.threads = []
def open_socket(self):
try:
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.bind((self.host,self.port))
self.server.listen(5)
except socket.error, (value,message):
if self.server:
self.server.close()
print "Could not open socket: " + message
sys.exit(1)
def run(self):
self.open_socket()
input = [self.server,sys.stdin]
running = 1
while running:
inputready,outputready,exceptready = select.select(input,[],[])
for s in inputready:
if s == self.server:
# handle the server socket
c = Client(self.server.accept())
c.start()
self.threads.append(c)
elif s == sys.stdin:
# handle standard input
junk = sys.stdin.readline()
running = 0
# close all threads
self.server.close()
for c in self.threads:
c.join()
class Client(threading.Thread):
def __init__(self,(client,address)):
threading.Thread.__init__(self)
self.client = client
self.address = address
self.size = 1024
def run(self):
running = 1
while running:
data = self.client.recv(self.size)
if data:
data2 = data.split()
if data2[0] == 'Hello':
status = 'Hello'
#fetch from database users by location
reply= '6'
if data2[0] == 'Index':
status = 'Index'
#fetch from database users by location
reply='I'
db = MySQLdb.connect(host="localhost", # your host, usually localhost
user="root", # your username
passwd="Rambo_9134", # your password
db="secure_login") # name of the data base
# you must create a Cursor object. It will let
# you execute all the queries you need
cur = db.cursor()
# Use all the SQL you like
cur.execute("SELECT ml.member,m.username FROM locations l JOIN memberlocation ml ON(l.id = ml.location) JOIN members m ON(m.id = ml.member) where l.id = 1;")
# print all the first cell of all the rows
data = []
for row in cur.fetchall() :
print row[1]
data.append({row[0]:row[1]})
print 'JSON', json.dumps(data)
reply = data
self.client.send(json.dumps(reply))
else:
self.client.close()
running = 0
if __name__ == "__main__":
s = Server()
s.run()
this script works fine, but it stops when i press enter button. I tried many alternatives: deamon, nohup, ... I couldn't get it to run as a service in the background. i think this is a programming problem
how can I make this script run in the background as a service?
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For a quick and easy way, in test / dev environment, you can use screen
.
screen -S mySessionName
This starts a new session named session mySessionName
and joins that session. Within this session, you can run your code.
Use Ctrl+ A, Dto disconnect from this session. Your code will continue to work.
To reconnect to this session use:
screen -r mySessionName
To show all sessions use:
screen -ls
In a work environment, however, you have to look supervisor
. This server-side question might help.
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