-"""
- NEPI, a framework to manage network experiments
- Copyright (C) 2013 INRIA
+#
+# NEPI, a framework to manage network experiments
+# Copyright (C) 2013 INRIA
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+#
+# Author: Alina Quereilhac <alina.quereilhac@inria.fr>
- 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 3 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, see <http://www.gnu.org/licenses/>.
+from nepi.util import guid
+from nepi.util.parallel import ParallelRun
+from nepi.util.timefuncs import tnow, tdiffsec, stabsformat, tsformat
+from nepi.execution.resource import ResourceFactory, ResourceAction, \
+ ResourceState, ResourceState2str
+from nepi.execution.scheduler import HeapScheduler, Task, TaskStatus
+from nepi.execution.trace import TraceAttr
-"""
+# TODO: use multiprocessing instead of threading
+# TODO: Allow to reconnect to a running experiment instance! (reconnect mode vs deploy mode)
+import functools
import logging
import os
import random
import time
import threading
-from nepi.util import guid
-from nepi.util.parallel import ParallelRun
-from nepi.util.timefuncs import strfnow, strfdiff, strfvalid
-from nepi.execution.resource import ResourceFactory, ResourceAction, \
- ResourceState
-from nepi.execution.scheduler import HeapScheduler, Task, TaskStatus
-from nepi.execution.trace import TraceAttr
-
-# TODO: use multiprocessing instead of threading
-# TODO: When a failure occurrs during deployment scp and ssh processes are left running behind!!
-
class ECState(object):
+ """ State of the Experiment Controller
+
+ """
RUNNING = 1
FAILED = 2
TERMINATED = 3
class ExperimentController(object):
- def __init__(self, exp_id = None, root_dir = "/tmp"):
+ """
+ .. class:: Class Args :
+
+ :param exp_id: Human readable identifier for the experiment scenario.
+ It will be used in the name of the directory
+ where experiment related information is stored
+ :type exp_id: str
+
+ .. note::
+
+ An experiment, or scenario, is defined by a concrete use, behavior,
+ configuration and interconnection of resources that describe a single
+ experiment case (We call this the experiment description).
+ A same experiment (scenario) can be run many times.
+
+ The ExperimentController (EC), is the entity responsible for
+ managing an experiment instance (run). The same scenario can be
+ recreated (and re-run) by instantiating an EC and recreating
+ the same experiment description.
+
+ In NEPI, an experiment is represented as a graph of interconnected
+ resources. A resource is a generic concept in the sense that any
+ component taking part of an experiment, whether physical of
+ virtual, is considered a resource. A resources could be a host,
+ a virtual machine, an application, a simulator, a IP address.
+
+ A ResourceManager (RM), is the entity responsible for managing a
+ single resource. ResourceManagers are specific to a resource
+ type (i.e. An RM to control a Linux application will not be
+ the same as the RM used to control a ns-3 simulation).
+ In order for a new type of resource to be supported in NEPI
+ a new RM must be implemented. NEPI already provides different
+ RMs to control basic resources, and new can be extended from
+ the existing ones.
+
+ Through the EC interface the user can create ResourceManagers (RMs),
+ configure them and interconnect them, in order to describe an experiment.
+ Describing an experiment through the EC does not run the experiment.
+ Only when the 'deploy()' method is invoked on the EC, will the EC take
+ actions to transform the 'described' experiment into a 'running' experiment.
+
+ While the experiment is running, it is possible to continue to
+ create/configure/connect RMs, and to deploy them to involve new
+ resources in the experiment (this is known as 'interactive' deployment).
+
+ An experiments in NEPI is identified by a string id,
+ which is either given by the user, or automatically generated by NEPI.
+ The purpose of this identifier is to separate files and results that
+ belong to different experiment scenarios.
+ However, since a same 'experiment' can be run many times, the experiment
+ id is not enough to identify an experiment instance (run).
+ For this reason, the ExperimentController has two identifier, the
+ exp_id, which can be re-used by different ExperimentController instances,
+ and the run_id, which unique to a ExperimentController instance, and
+ is automatically generated by NEPI.
+
+ """
+
+ def __init__(self, exp_id = None):
super(ExperimentController, self).__init__()
- # root directory to store files
- self._root_dir = root_dir
+ # Logging
+ self._logger = logging.getLogger("ExperimentController")
+
+ # Run identifier. It identifies a concrete instance (run) of an experiment.
+ # Since a same experiment (same configuration) can be run many times,
+ # this id permits to identify concrete exoeriment run
+ self._run_id = tsformat()
- # experiment identifier given by the user
- self._exp_id = exp_id or "nepi-exp-%s" % os.urandom(8).encode('hex')
+ # Experiment identifier. Usually assigned by the user
+ self._exp_id = exp_id or "exp-%s" % os.urandom(8).encode('hex')
# generator of globally unique ids
self._guid_generator = guid.GuidGenerator()
# Tasks
self._tasks = dict()
+ # RM groups
+ self._groups = dict()
+
+ # generator of globally unique id for groups
+ self._group_id_generator = guid.GuidGenerator()
+
# Event processing thread
self._cond = threading.Condition()
self._thread = threading.Thread(target = self._process)
# EC state
self._state = ECState.RUNNING
- # Logging
- self._logger = logging.getLogger("ExperimentController")
-
@property
def logger(self):
+ """ Return the logger of the Experiment Controller
+
+ """
return self._logger
@property
def ecstate(self):
+ """ Return the state of the Experiment Controller
+
+ """
return self._state
@property
def exp_id(self):
- exp_id = self._exp_id
- if not exp_id.startswith("nepi-"):
- exp_id = "nepi-" + exp_id
- return exp_id
+ """ Return the experiment id assigned by the user
+
+ """
+ return self._exp_id
+
+ @property
+ def run_id(self):
+ """ Return the experiment instance (run) identifier
+
+ """
+ return self._run_id
@property
def finished(self):
+ """ Put the state of the Experiment Controller into a final state :
+ Either TERMINATED or FAILED
+
+ """
return self.ecstate in [ECState.FAILED, ECState.TERMINATED]
def wait_finished(self, guids):
- while not all([self.state(guid) == ResourceState.FINISHED \
- for guid in guids]) and not self.finished:
- # We keep the sleep as large as possible to
- # decrese the number of RM state requests
- time.sleep(2)
-
+ """ Blocking method that wait until all the RM from the 'guid' list
+ reached the state FINISHED ( or STOPPED, FAILED or RELEASED )
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ return self.wait(guids)
+
+ def wait_started(self, guids):
+ """ Blocking method that wait until all the RM from the 'guid' list
+ reached the state STARTED ( or STOPPED, FINISHED, FAILED, RELEASED)
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ return self.wait(guids, state = ResourceState.STARTED)
+
+ def wait_released(self, guids):
+ """ Blocking method that wait until all the RM from the 'guid' list
+ reached the state RELEASED (or FAILED)
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ # TODO: solve state concurrency BUG and !!!!
+ # correct waited release state to state = ResourceState.FAILED)
+ return self.wait(guids, state = ResourceState.FINISHED)
+
+ def wait_deployed(self, guids):
+ """ Blocking method that wait until all the RM from the 'guid' list
+ reached the state READY (or any higher state)
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ return self.wait(guids, state = ResourceState.READY)
+
+ def wait(self, guids, state = ResourceState.STOPPED):
+ """ Blocking method that waits until all the RM from the 'guid' list
+ reached state 'state' or until a failure occurs
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ if isinstance(guids, int):
+ guids = [guids]
+
+ # we randomly alter the order of the guids to avoid ordering
+ # dependencies (e.g. LinuxApplication RMs runing on the same
+ # linux host will be synchronized by the LinuxNode SSH lock)
+ random.shuffle(guids)
+
+ while True:
+ # If no more guids to wait for or an error occured, then exit
+ if len(guids) == 0 or self.finished:
+ break
+
+ # If a guid reached one of the target states, remove it from list
+ guid = guids[0]
+ rstate = self.state(guid)
+
+ if rstate >= state:
+ guids.remove(guid)
+ else:
+ # Debug...
+ self.logger.debug(" WAITING FOR guid %d - state is %s, required is >= %s " % (guid,
+ self.state(guid, hr = True), state))
+
+ # Take the opportunity to 'refresh' the states of the RMs.
+ # Query only the first up to N guids (not to overwhelm
+ # the local machine)
+ n = 100
+ lim = n if len(guids) > n else ( len(guids) -1 )
+ nguids = guids[0: lim]
+
+ # schedule state request for all guids (take advantage of
+ # scheduler multi threading).
+ for guid in nguids:
+ callback = functools.partial(self.state, guid)
+ self.schedule("0s", callback)
+
+ # If the guid is not in one of the target states, wait and
+ # continue quering. We keep the sleep big to decrease the
+ # number of RM state queries
+ time.sleep(4)
+
def get_task(self, tid):
+ """ Get a specific task
+
+ :param tid: Id of the task
+ :type tid: int
+ :rtype: Task
+ """
return self._tasks.get(tid)
def get_resource(self, guid):
+ """ Get a specific Resource Manager
+
+ :param guid: Id of the task
+ :type guid: int
+ :rtype: ResourceManager
+ """
return self._resources.get(guid)
@property
def resources(self):
+ """ Returns the list of all the Resource Manager Id
+
+ :rtype: set
+
+ """
return self._resources.keys()
def register_resource(self, rtype, guid = None):
+ """ Register a Resource Manager. It creates a new 'guid', if it is not specified,
+ for the RM of type 'rtype' and add it to the list of Resources.
+
+ :param rtype: Type of the RM
+ :type rtype: str
+ :return: Id of the RM
+ :rtype: int
+ """
# Get next available guid
guid = self._guid_generator.next(guid)
return guid
def get_attributes(self, guid):
- rm = self.get_resource(guid)
- return rm.get_attributes()
+ """ Return all the attibutes of a specific RM
- def get_filters(self, guid):
+ :param guid: Guid of the RM
+ :type guid: int
+ :return: List of attributes
+ :rtype: list
+ """
rm = self.get_resource(guid)
- return rm.get_filters()
+ return rm.get_attributes()
def register_connection(self, guid1, guid2):
+ """ Registers a guid1 with a guid2.
+ The declaration order is not important
+
+ :param guid1: First guid to connect
+ :type guid1: ResourceManager
+
+ :param guid2: Second guid to connect
+ :type guid: ResourceManager
+ """
rm1 = self.get_resource(guid1)
rm2 = self.get_resource(guid2)
- rm1.connect(guid2)
- rm2.connect(guid1)
+ rm1.register_connection(guid2)
+ rm2.register_connection(guid1)
- def register_condition(self, group1, action, group2, state,
+ def register_condition(self, guids1, action, guids2, state,
time = None):
- """ Registers an action START or STOP for all RM on group1 to occur
- time 'time' after all elements in group2 reached state 'state'.
+ """ Registers an action START or STOP for all RM on guids1 to occur
+ time 'time' after all elements in guids2 reached state 'state'.
- :param group1: List of guids of RMs subjected to action
- :type group1: list
+ :param guids1: List of guids of RMs subjected to action
+ :type guids1: list
:param action: Action to register (either START or STOP)
:type action: ResourceAction
- :param group2: List of guids of RMs to we waited for
- :type group2: list
+ :param guids2: List of guids of RMs to we waited for
+ :type guids2: list
:param state: State to wait for on RMs (STARTED, STOPPED, etc)
:type state: ResourceState
- :param time: Time to wait after group2 has reached status
+ :param time: Time to wait after guids2 has reached status
:type time: string
"""
- if isinstance(group1, int):
- group1 = [group1]
- if isinstance(group2, int):
- group2 = [group2]
+ if isinstance(guids1, int):
+ guids1 = [guids1]
+ if isinstance(guids2, int):
+ guids2 = [guids2]
- for guid1 in group1:
+ for guid1 in guids1:
rm = self.get_resource(guid1)
- rm.register_condition(action, group2, state, time)
+ rm.register_condition(action, guids2, state, time)
- def register_trace(self, guid, name):
+ def enable_trace(self, guid, name):
""" Enable trace
:param name: Name of the trace
:type name: str
"""
rm = self.get_resource(guid)
- rm.register_trace(name)
+ rm.enable_trace(name)
+
+ def trace_enabled(self, guid, name):
+ """ Returns True if trace is enabled
+
+ :param name: Name of the trace
+ :type name: str
+ """
+ rm = self.get_resource(guid)
+ return rm.trace_enabled(name)
def trace(self, guid, name, attr = TraceAttr.ALL, block = 512, offset = 0):
""" Get information on collected trace
rm = self.get_resource(guid)
return rm.trace(name, attr, block, offset)
- def discover(self, guid, filters):
+ def discover(self, guid):
+ """ Discover a specific RM defined by its 'guid'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
- return rm.discover(filters)
+ return rm.discover()
+
+ def provision(self, guid):
+ """ Provision a specific RM defined by its 'guid'
- def provision(self, guid, filters):
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
- return rm.provision(filters)
+ return rm.provision()
def get(self, guid, name):
+ """ Get a specific attribute 'name' from the RM 'guid'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ :param name: attribute's name
+ :type name: str
+
+ """
rm = self.get_resource(guid)
return rm.get(name)
def set(self, guid, name, value):
+ """ Set a specific attribute 'name' from the RM 'guid'
+ with the value 'value'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ :param name: attribute's name
+ :type name: str
+
+ :param value: attribute's value
+
+ """
rm = self.get_resource(guid)
return rm.set(name, value)
- def state(self, guid):
+ def state(self, guid, hr = False):
+ """ Returns the state of a resource
+
+ :param guid: Resource guid
+ :type guid: integer
+
+ :param hr: Human readable. Forces return of a
+ status string instead of a number
+ :type hr: boolean
+
+ """
rm = self.get_resource(guid)
- return rm.state
+ state = rm.state
+
+ if hr:
+ return ResourceState2str.get(state)
+
+ return state
def stop(self, guid):
+ """ Stop a specific RM defined by its 'guid'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
return rm.stop()
def start(self, guid):
+ """ Start a specific RM defined by its 'guid'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
return rm.start()
- def set_with_conditions(self, name, value, group1, group2, state,
+ def set_with_conditions(self, name, value, guids1, guids2, state,
time = None):
""" Set value 'value' on attribute with name 'name' on all RMs of
- group1 when 'time' has elapsed since all elements in group2
+ guids1 when 'time' has elapsed since all elements in guids2
have reached state 'state'.
:param name: Name of attribute to set in RM
:param value: Value of attribute to set in RM
:type name: string
- :param group1: List of guids of RMs subjected to action
- :type group1: list
+ :param guids1: List of guids of RMs subjected to action
+ :type guids1: list
:param action: Action to register (either START or STOP)
:type action: ResourceAction
- :param group2: List of guids of RMs to we waited for
- :type group2: list
+ :param guids2: List of guids of RMs to we waited for
+ :type guids2: list
:param state: State to wait for on RMs (STARTED, STOPPED, etc)
:type state: ResourceState
- :param time: Time to wait after group2 has reached status
+ :param time: Time to wait after guids2 has reached status
:type time: string
"""
- if isinstance(group1, int):
- group1 = [group1]
- if isinstance(group2, int):
- group2 = [group2]
+ if isinstance(guids1, int):
+ guids1 = [guids1]
+ if isinstance(guids2, int):
+ guids2 = [guids2]
- for guid1 in group1:
+ for guid1 in guids1:
rm = self.get_resource(guid)
- rm.set_with_conditions(name, value, group2, state, time)
+ rm.set_with_conditions(name, value, guids2, state, time)
def stop_with_conditions(self, guid):
+ """ Stop a specific RM defined by its 'guid' only if all the conditions are true
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
return rm.stop_with_conditions()
def start_with_conditions(self, guid):
+ """ Start a specific RM defined by its 'guid' only if all the conditions are true
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
- return rm.start_with_condition()
+ return rm.start_with_conditions()
- def deploy(self, group = None, wait_all_ready = True):
- """ Deploy all resource manager in group
+ def deploy(self, guids = None, wait_all_ready = True, group = None):
+ """ Deploy all resource manager in guids list
- :param group: List of guids of RMs to deploy
- :type group: list
+ :param guids: List of guids of RMs to deploy
+ :type guids: list
:param wait_all_ready: Wait until all RMs are ready in
order to start the RMs
:type guid: int
+ :param group: Id of deployment group in which to deploy RMs
+ :type group: int
+
"""
self.logger.debug(" ------- DEPLOY START ------ ")
- stop = []
-
- def steps(rm):
- try:
- rm.deploy()
- rm.start_with_conditions()
-
- # Only if the RM has STOP conditions we
- # schedule a stop. Otherwise the RM will stop immediately
- if rm.conditions.get(ResourceAction.STOP):
- rm.stop_with_conditions()
- except:
- import traceback
- err = traceback.format_exc()
+ if not guids:
+ # If no guids list was indicated, all 'NEW' RMs will be deployed
+ guids = []
+ for guid in self.resources:
+ if self.state(guid) == ResourceState.NEW:
+ guids.append(guid)
- self._logger.error("Error occurred while deploying resources: %s" % err)
-
- # stop deployment
- stop.append(None)
+ if isinstance(guids, int):
+ guids = [guids]
+ # Create deployment group
+ new_group = False
if not group:
- group = self.resources
+ new_group = True
+ group = self._group_id_generator.next(guid)
+
+ if group not in self._groups:
+ self._groups[group] = []
- # Before starting deployment we disorder the group list with the
+ self._groups[group].extend(guids)
+
+ # Before starting deployment we disorder the guids list with the
# purpose of speeding up the whole deployment process.
- # It is likely that the user inserted in the 'group' list closely
- # resources resources one after another (e.g. all applications
+ # It is likely that the user inserted in the 'guids' list closely
+ # resources one after another (e.g. all applications
# connected to the same node can likely appear one after another).
# This can originate a slow down in the deployment since the N
# threads the parallel runner uses to processes tasks may all
# be taken up by the same family of resources waiting for the
- # same conditions.
- # If we disorder the group list, this problem can be mitigated
- random.shuffle(group)
+ # same conditions (e.g. LinuxApplications running on a same
+ # node share a single lock, so they will tend to be serialized).
+ # If we disorder the guids list, this problem can be mitigated.
+ random.shuffle(guids)
- threads = []
- for guid in group:
+ def wait_all_and_start(group):
+ reschedule = False
+
+ # Get all guids in group
+ guids = self._groups[group]
+
+ for guid in guids:
+ if self.state(guid) < ResourceState.READY:
+ reschedule = True
+ break
+
+ if reschedule:
+ callback = functools.partial(wait_all_and_start, group)
+ self.schedule("1s", callback)
+ else:
+ # If all resources are read, we schedule the start
+ for guid in guids:
+ rm = self.get_resource(guid)
+ self.schedule("0s", rm.start_with_conditions)
+
+ if wait_all_ready and new_group:
+ # Schedule a function to check that all resources are
+ # READY, and only then schedule the start.
+ # This aimes at reducing the number of tasks looping in the
+ # scheduler.
+ # Intead of having N start tasks, we will have only one for
+ # the whole group.
+ callback = functools.partial(wait_all_and_start, group)
+ self.schedule("1s", callback)
+
+ for guid in guids:
rm = self.get_resource(guid)
+ rm.deployment_group = group
+ self.schedule("0s", rm.deploy)
- if wait_all_ready:
- towait = list(group)
- towait.remove(guid)
- self.register_condition(guid, ResourceAction.START,
- towait, ResourceState.READY)
-
- thread = threading.Thread(target = steps, args = (rm,))
- threads.append(thread)
- thread.setDaemon(True)
- thread.start()
+ if not wait_all_ready:
+ self.schedule("1s", rm.start_with_conditions)
- while list(threads) and not self.finished and not stop:
- thread = threads[0]
- # Time out after 5 seconds to check EC not terminated
- thread.join(1)
- if not thread.is_alive():
- threads.remove(thread)
-
- if stop:
- # stop the scheduler
- self._stop_scheduler()
+ if rm.conditions.get(ResourceAction.STOP):
+ # Only if the RM has STOP conditions we
+ # schedule a stop. Otherwise the RM will stop immediately
+ self.schedule("2s", rm.stop_with_conditions)
- if self._thread.is_alive():
- self._thread.join()
+ def release(self, guids = None):
+ """ Release al RMs on the guids list or
+ all the resources if no list is specified
- raise RuntimeError, "Error occurred, interrupting deployment "
+ :param guids: List of RM guids
+ :type guids: list
- def release(self, group = None):
- if not group:
- group = self.resources
+ """
+ if not guids:
+ guids = self.resources
- threads = []
- for guid in group:
+ for guid in guids:
rm = self.get_resource(guid)
- thread = threading.Thread(target=rm.release)
- threads.append(thread)
- thread.setDaemon(True)
- thread.start()
-
- while list(threads) and not self.finished:
- thread = threads[0]
- # Time out after 5 seconds to check EC not terminated
- thread.join(5)
- if not thread.is_alive():
- threads.remove(thread)
+ self.schedule("0s", rm.release)
+ self.wait_released(guids)
+
def shutdown(self):
+ """ Shutdown the Experiment Controller.
+ Releases all the resources and stops task processing thread
+
+ """
self.release()
- self._stop_scheduler()
+ # Mark the EC state as TERMINATED
+ self._state = ECState.TERMINATED
+
+ # Notify condition to wake up the processing thread
+ self._notify()
if self._thread.is_alive():
self._thread.join()
def schedule(self, date, callback, track = False):
""" Schedule a callback to be executed at time date.
- date string containing execution time for the task.
+ :param date: string containing execution time for the task.
It can be expressed as an absolute time, using
timestamp format, or as a relative time matching
^\d+.\d+(h|m|s|ms|us)$
- callback code to be executed for the task. Must be a
+ :param callback: code to be executed for the task. Must be a
Python function, and receives args and kwargs
as arguments.
- track if set to True, the task will be retrivable with
+ :param track: if set to True, the task will be retrivable with
the get_task() method
+
+ :return : The Id of the task
"""
- timestamp = strfvalid(date)
-
+ timestamp = stabsformat(date)
task = Task(timestamp, callback)
task = self._scheduler.schedule(task)
if track:
self._tasks[task.id] = task
-
+
# Notify condition to wake up the processing thread
- self._cond.acquire()
- self._cond.notify()
- self._cond.release()
+ self._notify()
return task.id
def _process(self):
- runner = ParallelRun(maxthreads = 50)
+ """ Process scheduled tasks.
+
+ .. note::
+
+ The _process method is executed in an independent thread held by the
+ ExperimentController for as long as the experiment is running.
+
+ Tasks are scheduled by invoking the schedule method with a target callback.
+ The schedule method is given a execution time which controls the
+ order in which tasks are processed.
+
+ Tasks are processed in parallel using multithreading.
+ The environmental variable NEPI_NTHREADS can be used to control
+ the number of threads used to process tasks. The default value is 50.
+
+ Exception handling:
+
+ To execute tasks in parallel, an ParallelRunner (PR) object, holding
+ a pool of threads (workers), is used.
+ For each available thread in the PR, the next task popped from
+ the scheduler queue is 'put' in the PR.
+ Upon receiving a task to execute, each PR worker (thread) invokes the
+ _execute method of the EC, passing the task as argument.
+ This method, calls task.callback inside a try/except block. If an
+ exception is raised by the tasks.callback, it will be trapped by the
+ try block, logged to standard error (usually the console), and the EC
+ state will be set to ECState.FAILED.
+ The invocation of _notify immediately after, forces the processing
+ loop in the _process method, to wake up if it was blocked waiting for new
+ tasks to arrived, and to check the EC state.
+ As the EC is in FAILED state, the processing loop exits and the
+ 'finally' block is invoked. In the 'finally' block, the 'sync' method
+ of the PR is invoked, which forces the PR to raise any unchecked errors
+ that might have been raised by the workers.
+
+ """
+ nthreads = int(os.environ.get("NEPI_NTHREADS", "50"))
+
+ runner = ParallelRun(maxthreads = nthreads)
runner.start()
try:
while not self.finished:
self._cond.acquire()
- task = self._scheduler.next()
- self._cond.release()
+ task = self._scheduler.next()
+
if not task:
- # It there are not tasks in the tasks queue we need to
- # wait until a call to schedule wakes us up
- self._cond.acquire()
+ # No task to execute. Wait for a new task to be scheduled.
self._cond.wait()
- self._cond.release()
- else:
- # If the task timestamp is in the future the thread needs to wait
- # until time elapse or until another task is scheduled
- now = strfnow()
+ else:
+ # The task timestamp is in the future. Wait for timeout
+ # or until another task is scheduled.
+ now = tnow()
if now < task.timestamp:
- # Calculate time difference in seconds
- timeout = strfdiff(task.timestamp, now)
+ # Calculate timeout in seconds
+ timeout = tdiffsec(task.timestamp, now)
+
# Re-schedule task with the same timestamp
self._scheduler.schedule(task)
- # Sleep until timeout or until a new task awakes the condition
- self._cond.acquire()
+
+ task = None
+
+ # Wait timeout or until a new task awakes the condition
self._cond.wait(timeout)
- self._cond.release()
- else:
- # Process tasks in parallel
- runner.put(self._execute, task)
-
+
+ self._cond.release()
+
+ if task:
+ # Process tasks in parallel
+ runner.put(self._execute, task)
except:
import traceback
err = traceback.format_exc()
- self._logger.error("Error while processing tasks in the EC: %s" % err)
+ self.logger.error("Error while processing tasks in the EC: %s" % err)
self._state = ECState.FAILED
- finally:
+ finally:
+ self.logger.debug("Exiting the task processing loop ... ")
runner.sync()
-
- # Mark EC state as terminated
- if self.ecstate == ECState.RUNNING:
- self._state = ECState.TERMINATED
+ runner.destroy()
def _execute(self, task):
+ """ Executes a single task.
+
+ :param task: Object containing the callback to execute
+ :type task: Task
+
+ .. note::
+
+ If the invokation of the task callback raises an
+ exception, the processing thread of the ExperimentController
+ will be stopped and the experiment will be aborted.
+
+ """
# Invoke callback
task.status = TaskStatus.DONE
task.result = err
task.status = TaskStatus.ERROR
- self._logger.error("Error occurred while executing task: %s" % err)
+ self.logger.error("Error occurred while executing task: %s" % err)
- self._stop_scheduler()
+ # Set the EC to FAILED state (this will force to exit the task
+ # processing thread)
+ self._state = ECState.FAILED
+
+ # Notify condition to wake up the processing thread
+ self._notify()
# Propage error to the ParallelRunner
raise
- def _stop_scheduler(self):
- # Mark the EC as failed
- self._state = ECState.FAILED
-
- # Wake up the EC in case it was sleeping
+ def _notify(self):
+ """ Awakes the processing thread in case it is blocked waiting
+ for a new task to be scheduled.
+ """
self._cond.acquire()
self._cond.notify()
self._cond.release()
-
git://git.onelab.eu / nepi.git / blobdiff