#!/usr/bin/env python # -*- coding: utf-8 -*- # $Id: backendctl 1634 2013-04-12 15:36:36Z amelung $ # # Copyright (c) 2007-2009 Otto-von-Guericke-Universität, Magdeburg # # This file is part of ECSpooler. # """ This module contains functions to start/stop a backend or get status information from a backend. __main__ reads the command lines arguments and processes them. A configuration file must be avaiable for each backend with entries about spooler server's host and port as well as base port for the backend. If a port is already in use, we will try another one. """ import os, sys, time, socket, xmlrpclib import getopt from getpass import getpass # add parent directory to the system path sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__)), os.pardir)) # local imports from lib.util import settings from lib.util.servicecontrol import ServiceControl from backends import * # TODO: should be in config.py MAX_TRIALS = 15 class BackendControl(ServiceControl): """ """ @staticmethod def usage(): """ """ print """ Usage: backendctl [OPTION ...] BACKEND {start|stop|restart|status} OPTIONs are: -P port Port to bind/connect backend to, i.e. where to listen for new request. Default: First free port in the range of 5060 .. 5074. -S host Hostname or IP of the machine on which ECSpooler runs. Needed for registering a backend. Default: localhost -B port Port on which ECSpooler runs. Needed for registering a backend. Default: 5050 -u user Name of the user required for authentication when starting and registering to ECSpooler -p password Password of the user required for authentication when starting and registering to ECSpooler BACKEND Name of the backend to start|stop|restart|status. """ def __init__(self, name, spooler_host, spooler_port, backend_port, username=None, password=None): """ """ ServiceControl.__init__(self, name, backend_port, username=username, password=password) self.spooler_host = spooler_host self.spooler_port = spooler_port def start(self): """ @see: ServiceControl.start() """ # Run backend as nobody try: os.setuid(settings.NOBODY_UID) except os.error, e: print >> sys.stderr, "Cannot change uid:", e try: exec 'from backends.%s import %s' % (self.name.lower(), self.name) exec 'id = %s.%s.id' % (self.name, self.name,) except NameError, ne: print >> sys.stderr, "No such backend: '%s'" % self.name raise ne except AttributeError, ae: print >> sys.stderr, "No such backend: '%s'. Did you mean '%s'?" \ % (self.name, self.name.capitalize(),) raise ae exec 'version = %s.%s.version' % (self.name, self.name,) (backend, p)= self.__get_backend_instance() if backend: print >> sys.stdout, "Starting %s backend at %s" % (self.name, time.asctime()) print >> sys.stdout, " Hostname: %s" % self.host print >> sys.stdout, " Port: %i" % p print >> sys.stdout, "Registering to ECSpooler at '%s:%s'..." % (self.spooler_host, self.spooler_port) try: if sys.platform in ['unixware7']: cpid = os.fork1() else: cpid = os.fork() except AttributeError: print >> sys.stdout, 'os.fork not defined - skipping.' cpid = 0 if cpid == 0: # child process # blocks here 'til shutdown err_msg = backend.start() if err_msg: print >> sys.stderr, err_msg else: # parent process time.sleep(1) print >> sys.stdout, 'pid=%d' % cpid else: #print 'Backend start failed. See log for more information.' print >> sys.stderr, 'Backend start failed. See log for more information.' def __get_backend_instance(self): """ Returns an instance of the backend class if one could be created. """ # put together the backend module and class name using backend_id moduleName = '%s.%s' % (self.name, self.name,) for port in range(self.port, self.port + MAX_TRIALS, 1): # get a instance, e.g., Python-Backend # FIXME: use spooler instead of spooler instance_create_stmt = \ "backend = %s({ \ 'host': '%s', \ 'port': %d, \ 'spooler': 'http://%s:%d', \ 'auth': %s}, %s.__file__)" \ % (moduleName, self.host, port, \ self.spooler_host, self.spooler_port, \ repr(self._get_auth()), self.name) retval = self.__try_get_backend_instance(instance_create_stmt) if retval: return (retval, port) else: time.sleep(0.1) return (None, 0) def __try_get_backend_instance(self, instance_create_stmt): """ Executes the import statement for the backend class, creates an instance and returns this instance. An exception is thrown if the port is already in use. In this case we will return None. @param: instance_create_stmt Statement which will be executed to create a new instance of the backend class. @return: The backend instance or None if the instance couldn't be created. """ try: backend = None #log.debug("Trying to create instance of backend '%s'" % self.name) #log.debug(instance_create_stmt) exec 'from backends.%s import %s' % (self.name.lower(), self.name) exec(instance_create_stmt) return backend # FIXME: This doesn't work on Windows -> no socket.error is thrown if # port is already in use! except socket.error: return None def _process_stop(self): """ @see ServiceControl.stop @see ServiceControl._process_stop """ backend = xmlrpclib.ServerProxy("http://%s:%d" % (self.host, self.port)) result = backend.shutdown(self._get_auth(), self.name) print >> sys.stdout, result def _process_status(self): """ @see ServiceControl.status @see ServiceControl._process_status """ server = xmlrpclib.ServerProxy("http://%s:%d" % (self.host, self.port)) return server.getStatus(self._get_auth(), self.name) # ----------------------------------------------------------------------------- def main(): """ """ try: opts, args = getopt.getopt(sys.argv[1:], "S:B:P:u:p:h", ["spoolerhost=", "spoolerport=", "backendport=", "user=", "password=", "help"]) except getopt.GetoptError: # print help information and exit: BackendControl.usage() sys.exit(2) if len(args) != 2: BackendControl.usage() sys.exit(2) else: spooler_host = 'localhost' spooler_port = 5050 backend_port = 5060 user = None password = None for o, a in opts: if o in ("-h", "--help"): BackendControl.usage() sys.exit() if o in ("-S", "--spoolerhost"): spooler_host = a if o in ("-B", "--spoolerport"): try: spooler_port = int(a) except ValueError: BackendControl.usage() sys.exit(2) if o in ("-u", "--user"): user = a if o in ("-p", "--password"): password = a if o in ("-P", "--backendport"): try: backend_port = int(a) except ValueError: BackendControl.usage() sys.exit(2) backend_id, cmd = args settings.init_logging(backend_id.lower()) if not user: user = raw_input("Username for ECSpooler: ") if not password: password = getpass("Password for ECSpooler: ") if not user or not password: print "%s requires username and password." % cmd BackendControl.usage() sys.exit(2) backendctl = BackendControl(backend_id, spooler_host, spooler_port, backend_port, user, password) backendctl.process(cmd) # -- Main ---------------------------------------------------------------------- if __name__ == "__main__": main()