Server - daemon

diff --git a/server/Server.py b/server/Server.py
new file mode 100644 (file)
index 0000000..e7bba46
--- /dev/null
+++ b/server/Server.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+# TODO: listen, receive on port 
+
+import sys, time, os
+from daemon import Daemon
+
+def doServer():
+       #fin = open("/home/adriana/t.txt", "rw");
+       #print >> fin, "hello"
+
+       os.spawnvp(os.P_NOWAIT,"/usr/bin/transmission",[])
+       #fin.close()
+
+class MyDaemon(Daemon):
+       def run(self):
+       #       os.spawnvp(os.P_NOWAIT,"/usr/bin/transmission",[])
+               doServer()      
+       
+if __name__ == "__main__":
+       daemon = MyDaemon('/tmp/daemon-example.pid')
+       if len(sys.argv) == 2:
+               if 'start' == sys.argv[1]:
+                       daemon.start()
+               elif 'stop' == sys.argv[1]:
+                       daemon.stop()
+               elif 'restart' == sys.argv[1]:
+                       daemon.restart()
+               else:
+                       print "Unknown command"
+                       sys.exit(2)
+               sys.exit(0)
+       else:
+               print "usage: %s start|stop|restart" % sys.argv[0]
+               sys.exit(2)
+
+

diff --git a/server/daemon.py b/server/daemon.py
new file mode 100644 (file)
index 0000000..f371720
--- /dev/null
+++ b/server/daemon.py
@@ -0,0 +1,129 @@
+#!/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().
+               """