Source code for pypdevs.middleware
# Copyright 2014 Modelling, Simulation and Design Lab (MSDL) at
# McGill University and the University of Antwerp (http://msdl.cs.mcgill.ca/)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Middleware detection and setup code
"""
import sys
[docs]def startupMiddleware():
"""
Do the actual detection and startup, also defines all necessary globals
:returns: tuple -- current server rank and total world size
"""
if "MPI" in globals():
# Force local simulation
return 0, 1
# Try loading MPI
global COMM_WORLD
global MPI
try:
from mpi4py import MPI
COMM_WORLD = MPI.COMM_WORLD
except ImportError:
# No MPI4Py found, so force local MPI simulation
from pypdevs.MPIRedirect import MPIFaker
COMM_WORLD = MPIFaker()
# Now we should take care of the starting of the server
rank = COMM_WORLD.Get_rank()
if rank != 0:
# We should stop immediately, to prevent multiple constructions of the model
# This is a 'good' stop, so return with a zero
from pypdevs.server import Server
server = Server(int(rank), COMM_WORLD.Get_size())
sys.exit(0)
else:
# We should still shutdown every simulation kernel at exit by having the controller send these messages
# Use the atexit code at the end
if COMM_WORLD.Get_size() > 1:
import atexit
atexit.register(cleanupMPI)
return 0, COMM_WORLD.Get_size()
[docs]def cleanupMPI():
"""
Shut down the MPI backend by sending a termination message to all listening nodes
"""
for i in range(COMM_WORLD.Get_size()):
if i == COMM_WORLD.Get_rank():
req = COMM_WORLD.isend(0, dest=i, tag=0)
else:
COMM_WORLD.send(0, dest=i, tag=0)
if COMM_WORLD.Get_size() > 1:
MPI.Request.wait(req)