#!/usr/bin/python -u
#

# Copyright (C) 2006, 2007 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.


"""Master daemon program.

Some classes deviates from the standard style guide since the
inheritance from parent classes requires it.

"""


import sys
import SocketServer
import threading
import time
import collections
import Queue
import random
import signal
import simplejson


from cStringIO import StringIO
from optparse import OptionParser

from ganeti import constants
from ganeti import mcpu
from ganeti import opcodes
from ganeti import jqueue
from ganeti import luxi
from ganeti import utils
from ganeti import errors
from ganeti import ssconf


EXIT_NOTMASTER = constants.EXIT_NOTMASTER
EXIT_NODESETUP_ERROR = constants.EXIT_NODESETUP_ERROR


class IOServer(SocketServer.UnixStreamServer):
  """IO thread class.

  This class takes care of initializing the other threads, setting
  signal handlers (which are processed only in this thread), and doing
  cleanup at shutdown.

  """
  QUEUE_PROCESSOR_SIZE = 1

  def __init__(self, address, rqhandler):
    SocketServer.UnixStreamServer.__init__(self, address, rqhandler)
    self.do_quit = False
    self.queue = jqueue.QueueManager()
    self.processors = []
    signal.signal(signal.SIGINT, self.handle_quit_signals)
    signal.signal(signal.SIGTERM, self.handle_quit_signals)

  def setup_processors(self):
    """Spawn the processors threads.

    This initializes the queue and the thread processors. It is done
    separately from the constructor because we want the clone()
    syscalls to happen after the daemonize part.

    """
    for i in range(self.QUEUE_PROCESSOR_SIZE):
      self.processors.append(threading.Thread(target=PoolWorker,
                                              args=(i, self.queue.new_queue)))
    for t in self.processors:
      t.start()

  def process_request_thread(self, request, client_address):
    """Process the request.

    This is copied from the code in ThreadingMixIn.

    """
    try:
      self.finish_request(request, client_address)
      self.close_request(request)
    except:
      self.handle_error(request, client_address)
      self.close_request(request)

  def process_request(self, request, client_address):
    """Start a new thread to process the request.

    This is copied from the coode in ThreadingMixIn.

    """
    t = threading.Thread(target=self.process_request_thread,
                         args=(request, client_address))
    t.start()

  def handle_quit_signals(self, signum, frame):
    print "received %s in %s" % (signum, frame)
    self.do_quit = True

  def serve_forever(self):
    """Handle one request at a time until told to quit."""
    while not self.do_quit:
      self.handle_request()
      print "served request, quit=%s" % (self.do_quit)

  def server_cleanup(self):
    """Cleanup the server.

    This involves shutting down the processor threads and the master
    socket.

    """
    self.server_close()
    utils.RemoveFile(constants.MASTER_SOCKET)
    for i in range(self.QUEUE_PROCESSOR_SIZE):
      self.queue.new_queue.put(None)
    for idx, t in enumerate(self.processors):
      print "waiting for processor thread %s..." % idx
      t.join()
    print "done threads"


class ClientRqHandler(SocketServer.BaseRequestHandler):
  """Client handler"""
  EOM = '\3'
  READ_SIZE = 4096

  def setup(self):
    self._buffer = ""
    self._msgs = collections.deque()
    self._ops = ClientOps(self.server)

  def handle(self):
    while True:
      msg = self.read_message()
      if msg is None:
        print "client closed connection"
        break
      request = simplejson.loads(msg)
      if not isinstance(request, dict):
        print "wrong request received: %s" % msg
        break
      method = request.get('request', None)
      data = request.get('data', None)
      if method is None or data is None:
        print "no method or data in request"
        break
      print "request:", method, data
      result = self._ops.handle_request(method, data)
      print "result:", result
      self.send_message(simplejson.dumps({'success': True, 'result': result}))

  def read_message(self):
    while not self._msgs:
      data = self.request.recv(self.READ_SIZE)
      if not data:
        return None
      new_msgs = (self._buffer + data).split(self.EOM)
      self._buffer = new_msgs.pop()
      self._msgs.extend(new_msgs)
    return self._msgs.popleft()

  def send_message(self, msg):
    #print "sending", msg
    self.request.sendall(msg + self.EOM)


class ClientOps:
  """Class holding high-level client operations."""
  def __init__(self, server):
    self.server = server
    self._cpu = None

  def _getcpu(self):
    if self._cpu is None:
      self._cpu = mcpu.Processor(lambda x: None)
    return self._cpu

  def handle_request(self, operation, args):
    print operation, args
    if operation == "submit":
      return self.put(args)
    elif operation == "query":
      return self.query(args)
    else:
      raise ValueError("Invalid operation")

  def put(self, args):
    job = luxi.UnserializeJob(args)
    rid = self.server.queue.put(job)
    return rid

  def query(self, args):
    path = args["object"]
    fields = args["fields"]
    names = args["names"]
    if path == "instances":
      opclass = opcodes.OpQueryInstances
    elif path == "jobs":
      # early exit because job query-ing is special (not via opcodes)
      return self.query_jobs(fields, names)
    else:
      raise ValueError("Invalid object %s" % path)

    op = opclass(output_fields = fields, names=names)
    cpu = self._getcpu()
    result = cpu.ExecOpCode(op)
    return result

  def query_jobs(self, fields, names):
    return self.server.queue.query_jobs(fields, names)


def JobRunner(proc, job):
  """Job executor.

  This functions processes a single job in the context of given
  processor instance.

  """
  job.SetStatus(opcodes.Job.STATUS_RUNNING)
  fail = False
  for idx, op in enumerate(job.data.op_list):
    job.data.op_status[idx] = opcodes.Job.STATUS_RUNNING
    try:
      job.data.op_result[idx] = proc.ExecOpCode(op)
      job.data.op_status[idx] = opcodes.Job.STATUS_SUCCESS
    except (errors.OpPrereqError, errors.OpExecError), err:
      fail = True
      job.data.op_result[idx] = str(err)
      job.data.op_status[idx] = opcodes.Job.STATUS_FAIL
  if fail:
    job.SetStatus(opcodes.Job.STATUS_FAIL)
  else:
    job.SetStatus(opcodes.Job.STATUS_SUCCESS)


def PoolWorker(worker_id, incoming_queue):
  """A worker thread function.

  This is the actual processor of a single thread of Job execution.

  """
  while True:
    print "worker %s sleeping" % worker_id
    item = incoming_queue.get(True)
    if item is None:
      break
    print "worker %s processing job %s" % (worker_id, item.data.job_id)
    #utils.Lock('cmd')
    try:
      proc = mcpu.Processor(feedback=lambda x: None)
      try:
        JobRunner(proc, item)
      except errors.GenericError, err:
        print "ganeti exception %s" % err
    finally:
      #utils.Unlock('cmd')
      #utils.LockCleanup()
      pass
    print "worker %s finish job %s" % (worker_id, item.data.job_id)
  print "worker %s exiting" % worker_id


def CheckMaster(debug):
  """Checks the node setup.

  If this is the master, the function will return. Otherwise it will
  exit with an exit code based on the node status.

  """
  try:
    ss = ssconf.SimpleStore()
    master_name = ss.GetMasterNode()
  except errors.ConfigurationError, err:
    print "Cluster configuration incomplete: '%s'" % str(err)
    sys.exit(EXIT_NODESETUP_ERROR)

  try:
    myself = utils.HostInfo()
  except errors.ResolverError, err:
    sys.stderr.write("Cannot resolve my own name (%s)\n" % err.args[0])
    sys.exit(EXIT_NODESETUP_ERROR)

  if myself.name != master_name:
    if debug:
      sys.stderr.write("Not master, exiting.\n")
    sys.exit(EXIT_NOTMASTER)


def ParseOptions():
  """Parse the command line options.

  Returns:
    (options, args) as from OptionParser.parse_args()

  """
  parser = OptionParser(description="Ganeti master daemon",
                        usage="%prog [-f] [-d]",
                        version="%%prog (ganeti) %s" %
                        constants.RELEASE_VERSION)

  parser.add_option("-f", "--foreground", dest="fork",
                    help="Don't detach from the current terminal",
                    default=True, action="store_false")
  parser.add_option("-d", "--debug", dest="debug",
                    help="Enable some debug messages",
                    default=False, action="store_true")
  options, args = parser.parse_args()
  return options, args


def main():
  """Main function"""

  options, args = ParseOptions()
  utils.debug = options.debug

  CheckMaster(options.debug)

  master = IOServer(constants.MASTER_SOCKET, ClientRqHandler)

  # become a daemon
  if options.fork:
    utils.Daemonize(logfile=constants.LOG_MASTERDAEMON,
                    noclose_fds=[master.fileno()])

  master.setup_processors()
  try:
    master.serve_forever()
  finally:
    master.server_cleanup()

if __name__ == "__main__":
  main()