def run(self):
"""
Start the master and connect it to the server indicated in the
configuration file.
"""
url = urlparse.urlparse(self.url)
self.connect((url.hostname, url.port or 80))
HTTPClient.run(self)
def __init__(self, nick, fconf):
"""
Create a Master client/server
@param nick a friendly name string for identification
@param fconf path to the configuration file
"""
Logger.__init__(self, "Master")
HTTPClient.__init__(self)
self.fconf = fconf
self.conf = json.load(open(fconf))
# This keep track of the statistics of the master. See status.py
self.status = MasterStatus()
# Set to true if the registration was succesful
self.registered = False
self.unique_id = -1
# Marks the end of the stream. The server has no more maps to execute.
# Set to true whenever a end-of-stream message is received
self.end_of_stream = False
self.comm = MPI.COMM_WORLD
self.n_machines = count_machines(self.conf["machine-file"])
# The mux object.
self.communicators = None
# The lock is used to synchronize the access to units_to_kill variable
# which will be accessed by two different threads, namely the one
# interacting with server and the one interacting with the workers
self.kill_lock = Lock()
self.units_to_kill = 0
self.info("We have %d available slots" % (self.n_machines))
self.nick = nick
self.url = self.conf['master-url']
self.sleep_inter = self.conf['sleep-interval']
# Generic lock to synchronize the access to the instance variables of
# the object itself. Its use should be minimized.
self.lock = Lock()
# Integer marking the number of maps which are currently being
# executed. Incremented on assignment, decremented on finish.
self.num_map = 0
# Simple queue of WorkerStatus(TYPE_MAP, ..) objects. Filled whenever
# the server returns us a compute-map message.
self.map_queue = []
# An event that whenever is set marks the end of the computation, set
# upon reception of the plz-die message
self.ev_finished = Event()
# Maximum number of simultaneous files that the reduce may manage in
# one row. Usually should be set to the MAX_FD of the system.
self.threshold_nfile = int(self.conf["threshold-nfile"])
# Simple lock that synchronize access to reduc* instance variables.
self.reduce_lock = Lock()
# This holds the triples in the sense that for each reduce we have
# a nested list which integers representing output of the mappers.
# If we have two reducers we will have for example:
# [
# [(0, 45), (1, 32), (3, 331)],
# [(5, 22), (6, 99)]
# ]
# Meaning:
# Reduce #1: -> output-reduce-000000-000000, 45 bytes
# -> output-reduce-000000-000001, 32 bytes
# -> output-reduce-000000-000003, 331 bytes
# Reduce #2: -> output-reduce-000001-000005, 22 bytes
# -> output-reduce-000001-000006, 99 bytes
self.reducing_files = []
# It will contain boolean values indicating the status of the reducers
self.reduce_started = []
for _ in xrange(int(self.conf['num-reducer'])):
self.reduce_started.append(False)
self.reducing_files.append([])
# The timer will be used to unlock the semaphore that is used as
# bounding mechanism for requesting new jobs to the server.
self.timer = None
self.num_pending_request = Semaphore(self.n_machines)
# Here we start two simple thread one in charge of executing requests
# and the other which is in charge of executing the main loop. There is
# also another thread executing asyncore.loop that manages the http
# communication with the server.
self.requester_thread = Thread(target=self.__requester_thread)
self.main_thread = Thread(target=self.__main_loop)
