#!/usr/bin/env python

__copyright__ = "Copyright 2013-2014, http://radical.rutgers.edu"
__license__   = "MIT"

import sys
import radical.pilot as rp

# READ: The RADICAL-Pilot documentation: 
#   http://radicalpilot.readthedocs.org/en/latest
#
# Try running this example with RADICAL_PILOT_VERBOSE=debug set if 
# you want to see what happens behind the scenes!


#------------------------------------------------------------------------------
#
def pilot_state_cb (pilot, state):
    



#------------------------------------------------------------------------------
#
def unit_state_cb (unit, state):
    """ this callback is invoked on all unit state changes """

    print "[Callback]: ComputeUnit  '%s' state: %s." % (unit.uid, state)

    if state == rp.FAILED:
        sys.exit (1)


# ------------------------------------------------------------------------------
#
if __name__ == "__main__":

    # we can optionally pass session name to RP
    if len(sys.argv) > 1:
        session_name = sys.argv[1]
    else:
        session_name = None

    # Create a new session. No need to try/except this: if session creation
    # fails, there is not much we can do anyways...
    session = rp.Session(name=session_name)
    print "session id: %s" % session.uid

    # all other pilot code is now tried/excepted.  If an exception is caught, we
    # can rely on the session object to exist and be valid, and we can thus tear
    # the whole RP stack down via a 'session.close()' call in the 'finally'
    # clause...
    try:

        # Add a Pilot Manager. Pilot managers manage one or more ComputePilots.
        pmgr = rp.PilotManager(session=session)
    
        # Register our callback with the PilotManager. This callback will get
        # called every time any of the pilots managed by the PilotManager
        # change their state.
        pmgr.register_callback(pilot_state_cb)
    
        # Define a X-core on stamped that runs for N minutes and
        # uses $HOME/radical.pilot.sandbox as sandbox directoy. 
        pdesc = rp.ComputePilotDescription()
        pdesc.resource = "xsede.stampede"
        pdesc.runtime  = 15 # N minutes
        pdesc.cores    = 16 # X cores
        pdesc.project  = "TG-MCB090174"
    
        # Launch the pilot.
        pilot = pmgr.submit_pilots(pdesc)
    
        cud_list = []
    
        for unit_count in range(0, 4):
            cu = rp.ComputeUnitDescription()
            cu.pre_exec      = ["module load python intel mvapich2 mpi4py"]
            cu.executable    = "python"
            cu.arguments     = ["helloworld_mpi.py"]
            cu.input_staging = ["helloworld_mpi.py"]
    
            # These two parameters are relevant to MPI execution:
            #   'cores' sets the number of cores required by the task
            #   'mpi' identifies the task as an MPI taskg
            cu.cores         = 8
            cu.mpi           = True
    
    
            cud_list.append(cu)
    
        # Combine the ComputePilot, the ComputeUnits and a scheduler via
        # a UnitManager object.
        umgr = rp.UnitManager(
            session=session,
            scheduler=rp.SCHED_DIRECT_SUBMISSION)
    
        # Register our callback with the UnitManager. This callback will get
        # called every time any of the units managed by the UnitManager
        # change their state.
        umgr.register_callback(unit_state_cb)
    
        # Add the previously created ComputePilot to the UnitManager.
        umgr.add_pilots(pilot)
    
        # Submit the previously created ComputeUnit descriptions to the
        # PilotManager. This will trigger the selected scheduler to start
        # assigning ComputeUnits to the ComputePilots.
        units = umgr.submit_units(cud_list)
    
        # Wait for all compute units to reach a terminal state (DONE or FAILED).
        umgr.wait_units()
    
        if not isinstance(units, list):
            units = [units]
        for unit in units:
            print "* Task %s - state: %s, exit code: %s, started: %s, finished: %s, stdout: %s" \
                % (unit.uid, unit.state, unit.exit_code, unit.start_time, unit.stop_time, unit.stdout)
    
    except Exception as e:
        # Something unexpected happened in the pilot code above
        print "caught Exception: %s" % e
        raise

    except (KeyboardInterrupt, SystemExit) as e:
        # the callback called sys.exit(), and we can here catch the
        # corresponding KeyboardInterrupt exception for shutdown.  We also catch
        # SystemExit (which gets raised if the main threads exits for some other
        # reason).
        print "need to exit now: %s" % e

    finally:
        # always clean up the session, no matter if we caught an exception or
        # not.
        print "closing session"
        session.close ()

        # the above is equivalent to
        #
        #   session.close (cleanup=True, terminate=True)
        #
        # it will thus both clean out the session's database record, and kill
        # all remaining pilots (none in our example).


#-------------------------------------------------------------------------------


""" this callback is invoked on all pilot state changes """

    print "[Callback]: ComputePilot '%s' state: %s." % (pilot.uid, state)

    if state == rp.FAILED:
        sys.exit (1)