X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=src%2Fnepi%2Fexecution%2Fec.py;h=257742eef99b14d69fdb9178b4a8b4cc4711132b;hb=304b2e9983206c904e0b3b3dbfeadc605969f332;hp=aa8351792fa33e10bbf0ecb593736e46ab4369fe;hpb=752d0aaffb889011159fef73c02d838e538d7144;p=nepi.git diff --git a/src/nepi/execution/ec.py b/src/nepi/execution/ec.py index aa835179..257742ee 100644 --- a/src/nepi/execution/ec.py +++ b/src/nepi/execution/ec.py @@ -31,53 +31,57 @@ from nepi.execution.trace import TraceAttr import functools import logging import os -import random import sys import time import threading import weakref class FailureLevel(object): - """ Describes the system failure state - """ + """ Describes the system failure state """ OK = 1 RM_FAILURE = 2 EC_FAILURE = 3 class FailureManager(object): - """ The FailureManager is responsible for handling errors, - and deciding whether an experiment should be aborted + """ The FailureManager is responsible for handling errors + and deciding whether an experiment should be aborted or not + """ def __init__(self, ec): self._ec = weakref.ref(ec) self._failure_level = FailureLevel.OK + self._abort = False @property def ec(self): - """ Returns the Experiment Controller """ + """ Returns the ExperimentController associated to this FailureManager + + """ + return self._ec() @property def abort(self): + return self._abort + + def eval_failure(self, guid): if self._failure_level == FailureLevel.OK: - for guid in self.ec.resources: - state = self.ec.state(guid) - critical = self.ec.get(guid, "critical") - if state == ResourceState.FAILED and critical: - self._failure_level = FailureLevel.RM_FAILURE - self.ec.logger.debug("RM critical failure occurred on guid %d." \ - " Setting EC FAILURE LEVEL to RM_FAILURE" % guid) - break + rm = self.ec.get_resource(guid) + state = rm.state + critical = rm.get("critical") - return self._failure_level != FailureLevel.OK + if state == ResourceState.FAILED and critical: + self._failure_level = FailureLevel.RM_FAILURE + self._abort = True + self.ec.logger.debug("RM critical failure occurred on guid %d." \ + " Setting EC FAILURE LEVEL to RM_FAILURE" % guid) def set_ec_failure(self): self._failure_level = FailureLevel.EC_FAILURE - class ECState(object): - """ State of the Experiment Controller + """ Possible states for an ExperimentController """ RUNNING = 1 @@ -93,62 +97,63 @@ class ExperimentController(object): .. note:: - An experiment, or scenario, is defined by a concrete set of resources, - behavior, configuration and interconnection of those resources. - The Experiment Description (ED) is a detailed representation of a - single experiment. It contains all the necessary information to - allow repeating the experiment. NEPI allows to describe - experiments by registering components (resources), configuring them - and interconnecting them. - - A same experiment (scenario) can be executed many times, generating - different results. We call an experiment execution (instance) a 'run'. - - The ExperimentController (EC), is the entity responsible of - managing an experiment 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). - To support a new type of resource in NEPI, a new RM must be - implemented. NEPI already provides a variety of - 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, 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, the EC will 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 in different ExperimentController, - and the run_id, which is unique to one ExperimentController instance, and - is automatically generated by NEPI. + An experiment, or scenario, is defined by a concrete set of resources, + behavior, configuration and interconnection of those resources. + The Experiment Description (ED) is a detailed representation of a + single experiment. It contains all the necessary information to + allow repeating the experiment. NEPI allows to describe + experiments by registering components (resources), configuring them + and interconnecting them. + + A same experiment (scenario) can be executed many times, generating + different results. We call an experiment execution (instance) a 'run'. + + The ExperimentController (EC), is the entity responsible of + managing an experiment 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). + To support a new type of resource in NEPI, a new RM must be + implemented. NEPI already provides a variety of + 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, 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, the EC will 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 in different ExperimentController, + and the run_id, which is unique to one ExperimentController instance, and + is automatically generated by NEPI. """ def __init__(self, exp_id = None): super(ExperimentController, self).__init__() + # Logging self._logger = logging.getLogger("ExperimentController") @@ -195,7 +200,7 @@ class ExperimentController(object): # The runner is a pool of threads used to parallelize # execution of tasks - nthreads = int(os.environ.get("NEPI_NTHREADS", "50")) + nthreads = int(os.environ.get("NEPI_NTHREADS", "20")) self._runner = ParallelRun(maxthreads = nthreads) # Event processing thread @@ -203,46 +208,70 @@ class ExperimentController(object): self._thread = threading.Thread(target = self._process) self._thread.setDaemon(True) self._thread.start() - + @property def logger(self): - """ Return the logger of the Experiment Controller + """ Returns the logger instance of the Experiment Controller """ return self._logger + @property + def failure_level(self): + """ Returns the level of FAILURE of th experiment + + """ + + return self._fm._failure_level + @property def ecstate(self): - """ Return the state of the Experiment Controller + """ Returns the state of the Experiment Controller """ return self._state @property def exp_id(self): - """ Return the experiment id assigned by the user + """ Returns the experiment id assigned by the user """ return self._exp_id @property def run_id(self): - """ Return the experiment instance (run) identifier + """ Returns the experiment instance (run) identifier (automatically + generated) """ return self._run_id @property def abort(self): + """ Returns True if the experiment has failed and should be interrupted, + False otherwise. + + """ return self._fm.abort - def wait_finished(self, guids): - """ Blocking method that wait until all RMs in the 'guid' list - reach a state >= STOPPED (i.e. FINISHED, STOPPED, FAILED or - RELEASED ) or until a System Failure occurs (e.g. Task Failure) + def inform_failure(self, guid): + """ Reports a failure in a RM to the EC for evaluation - :param guids: List of guids - :type guids: list + :param guid: Resource id + :type guid: int + + """ + + return self._fm.eval_failure(guid) + + def wait_finished(self, guids): + """ Blocking method that waits until all RMs in the 'guids' list + have reached a state >= STOPPED (i.e. STOPPED, FAILED or + RELEASED ), or until a failure in the experiment occurs + (i.e. abort == True) + + :param guids: List of guids + :type guids: list """ @@ -253,12 +282,13 @@ class ExperimentController(object): quit = quit) def wait_started(self, guids): - """ Blocking method that wait until all RMs in the 'guid' list - reach a state >= STARTED or until a System Failure occurs - (e.g. Task Failure) + """ Blocking method that waits until all RMs in the 'guids' list + have reached a state >= STARTED, or until a failure in the + experiment occurs (i.e. abort == True) + + :param guids: List of guids + :type guids: list - :param guids: List of guids - :type guids: list """ def quit(): @@ -268,11 +298,12 @@ class ExperimentController(object): quit = quit) def wait_released(self, guids): - """ Blocking method that wait until all RMs in the 'guid' list - reach a state = RELEASED or until the EC fails + """ Blocking method that waits until all RMs in the 'guids' list + have reached a state == RELEASED, or until the EC fails + + :param guids: List of guids + :type guids: list - :param guids: List of guids - :type guids: list """ def quit(): @@ -282,12 +313,13 @@ class ExperimentController(object): quit = quit) def wait_deployed(self, guids): - """ Blocking method that wait until all RMs in the 'guid' list - reach a state >= READY or until a System Failure occurs - (e.g. Task Failure) + """ Blocking method that waits until all RMs in the 'guids' list + have reached a state >= READY, or until a failure in the + experiment occurs (i.e. abort == True) + + :param guids: List of guids + :type guids: list - :param guids: List of guids - :type guids: list """ def quit(): @@ -297,11 +329,13 @@ class ExperimentController(object): quit = quit) def wait(self, guids, state, quit): - """ Blocking method that wait until all RMs in the 'guid' list - reach a state >= 'state' or until quit yileds True + """ Blocking method that waits until all RMs in the 'guids' list + have reached a state >= 'state', or until the 'quit' callback + yields True - :param guids: List of guids - :type guids: list + :param guids: List of guids + :type guids: list + """ if isinstance(guids, int): guids = [guids] @@ -316,58 +350,72 @@ class ExperimentController(object): break # If a guid reached one of the target states, remove it from list - guid = guids[0] - rstate = self.state(guid) + guid = guids.pop() + rm = self.get_resource(guid) + rstate = rm.state - hrrstate = ResourceState2str.get(rstate) - hrstate = ResourceState2str.get(state) - if rstate >= state: - guids.remove(guid) - rm = self.get_resource(guid) self.logger.debug(" %s guid %d DONE - state is %s, required is >= %s " % ( - rm.get_rtype(), guid, hrrstate, hrstate)) + rm.get_rtype(), guid, rstate, state)) else: # Debug... self.logger.debug(" WAITING FOR guid %d - state is %s, required is >= %s " % ( - guid, hrrstate, hrstate)) + guid, rstate, state)) + + guids.append(guid) + time.sleep(0.5) def get_task(self, tid): - """ Get a specific task + """ Returns a task by its id - :param tid: Id of the task - :type tid: int - :rtype: 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 + """ Returns a registered ResourceManager by its guid - :param guid: Id of the task - :type guid: int - :rtype: ResourceManager + :param guid: Id of the task + :type guid: int + + :rtype: ResourceManager + """ - return self._resources.get(guid) + rm = self._resources.get(guid) + return rm + + def remove_resource(self, guid): + del self._resources[guid] @property def resources(self): - """ Returns the list of all the Resource Manager Id + """ Returns the set() of guids of all the ResourceManager - :rtype: set + :return: Set of all RM guids + :rtype: set """ - return self._resources.keys() + keys = self._resources.keys() + + return 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. + """ Registers a new ResourceManager of type 'rtype' in the experiment + + This method will assign a new 'guid' for the RM, if no guid + is specified. + + :param rtype: Type of the RM + :type rtype: str - :param rtype: Type of the RM - :type rtype: str - :return: Id of the RM - :rtype: int + :return: Guid of the RM + :rtype: int + """ # Get next available guid guid = self._guid_generator.next(guid) @@ -381,25 +429,47 @@ class ExperimentController(object): return guid def get_attributes(self, guid): - """ Return all the attibutes of a specific RM + """ Returns all the attributes of the RM with guid 'guid' + + :param guid: Guid of the RM + :type guid: int + + :return: List of attributes + :rtype: list - :param guid: Guid of the RM - :type guid: int - :return: List of attributes - :rtype: list """ rm = self.get_resource(guid) return rm.get_attributes() + def get_attribute(self, guid, name): + """ Returns the attribute 'name' of the RM with guid 'guid' + + :param guid: Guid of the RM + :type guid: int + + :param name: Name of the attribute + :type name: str + + :return: The attribute with name 'name' + :rtype: Attribute + + """ + rm = self.get_resource(guid) + return rm.get_attribute(name) + def register_connection(self, guid1, guid2): - """ Registers a guid1 with a guid2. - The declaration order is not important + """ Registers a connection between a RM with guid 'guid1' + and another RM with guid 'guid2'. + + The order of the in which the two guids are provided is not + important, since the connection relationship is symmetric. :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) @@ -409,19 +479,21 @@ class ExperimentController(object): def register_condition(self, guids1, action, guids2, state, time = None): - """ Registers an action START or STOP for all RM on guids1 to occur - time 'time' after all elements in guids2 reached state 'state'. + """ Registers an action START, STOP or DEPLOY for all RM on list + guids1 to occur at time 'time' after all elements in list guids2 + have reached state 'state'. :param guids1: List of guids of RMs subjected to action :type guids1: list - :param action: Action to register (either START or STOP) + :param action: Action to perform (either START, STOP or DEPLOY) :type action: ResourceAction :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) + :param state: State to wait for on RMs of list guids2 (STARTED, + STOPPED, etc) :type state: ResourceState :param time: Time to wait after guids2 has reached status @@ -438,49 +510,74 @@ class ExperimentController(object): rm.register_condition(action, guids2, state, time) def enable_trace(self, guid, name): - """ Enable trace + """ Enables a trace to be collected during the experiment run + + :param name: Name of the trace + :type name: str - :param name: Name of the trace - :type name: str """ rm = self.get_resource(guid) rm.enable_trace(name) def trace_enabled(self, guid, name): - """ Returns True if trace is enabled + """ Returns True if the trace of name 'name' is enabled + + :param name: Name of the trace + :type name: str - :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 + """ Returns information on a collected trace, the trace stream or + blocks (chunks) of the trace stream - :param name: Name of the trace - :type name: str + :param name: Name of the trace + :type name: str - :param attr: Can be one of: + :param attr: Can be one of: - TraceAttr.ALL (complete trace content), - - TraceAttr.STREAM (block in bytes to read starting at offset), + - TraceAttr.STREAM (block in bytes to read starting + at offset), - TraceAttr.PATH (full path to the trace file), - TraceAttr.SIZE (size of trace file). - :type attr: str + :type attr: str - :param block: Number of bytes to retrieve from trace, when attr is TraceAttr.STREAM - :type name: int + :param block: Number of bytes to retrieve from trace, when attr is + TraceAttr.STREAM + :type name: int - :param offset: Number of 'blocks' to skip, when attr is TraceAttr.STREAM - :type name: int + :param offset: Number of 'blocks' to skip, when attr is TraceAttr.STREAM + :type name: int + + :rtype: str - :rtype: str """ rm = self.get_resource(guid) return rm.trace(name, attr, block, offset) + def get_traces(self, guid): + """ Returns the list of the trace names of the RM with guid 'guid' + + :param guid: Guid of the RM + :type guid: int + + :return: List of trace names + :rtype: list + + """ + rm = self.get_resource(guid) + return rm.get_traces() + + def discover(self, guid): - """ Discover a specific RM defined by its 'guid' + """ Discovers an available resource matching the criteria defined + by the RM with guid 'guid', and associates that resource to the RM + + Not all RM types require (or are capable of) performing resource + discovery. For the RM types which are not capable of doing so, + invoking this method does not have any consequences. :param guid: Guid of the RM :type guid: int @@ -490,7 +587,12 @@ class ExperimentController(object): return rm.discover() def provision(self, guid): - """ Provision a specific RM defined by its 'guid' + """ Provisions the resource associated to the RM with guid 'guid'. + + Provisioning means making a resource 'accessible' to the user. + Not all RM types require (or are capable of) performing resource + provisioning. For the RM types which are not capable of doing so, + invoking this method does not have any consequences. :param guid: Guid of the RM :type guid: int @@ -500,33 +602,68 @@ class ExperimentController(object): return rm.provision() def get(self, guid, name): - """ Get a specific attribute 'name' from the RM 'guid' + """ Returns the value of the attribute with name 'name' on the + RM with guid 'guid' :param guid: Guid of the RM :type guid: int - :param name: attribute's name + :param name: Name of the attribute :type name: str + :return: The value of the attribute with name 'name' + """ 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' + """ Modifies the value of the attribute with name 'name' on the + RM with guid 'guid'. :param guid: Guid of the RM :type guid: int - :param name: attribute's name + :param name: Name of the attribute :type name: str - :param value: attribute's value + :param value: Value of the attribute """ rm = self.get_resource(guid) - return rm.set(name, value) + rm.set(name, value) + + def get_global(self, rtype, name): + """ Returns the value of the global attribute with name 'name' on the + RMs of rtype 'rtype'. + + :param guid: Guid of the RM + :type guid: int + + :param name: Name of the attribute + :type name: str + + :return: The value of the attribute with name 'name' + + """ + rclass = ResourceFactory.get_resource_type(rtype) + return rclass.get_global(name) + + def set_global(self, rtype, name, value): + """ Modifies the value of the global attribute with name 'name' on the + RMs of with rtype 'rtype'. + + :param guid: Guid of the RM + :type guid: int + + :param name: Name of the attribute + :type name: str + + :param value: Value of the attribute + + """ + rclass = ResourceFactory.get_resource_type(rtype) + return rclass.set_global(name, value) def state(self, guid, hr = False): """ Returns the state of a resource @@ -548,7 +685,10 @@ class ExperimentController(object): return state def stop(self, guid): - """ Stop a specific RM defined by its 'guid' + """ Stops the RM with guid 'guid' + + Stopping a RM means that the resource it controls will + no longer take part of the experiment. :param guid: Guid of the RM :type guid: int @@ -558,7 +698,10 @@ class ExperimentController(object): return rm.stop() def start(self, guid): - """ Start a specific RM defined by its 'guid' + """ Starts the RM with guid 'guid' + + Starting a RM means that the resource it controls will + begin taking part of the experiment. :param guid: Guid of the RM :type guid: int @@ -567,11 +710,46 @@ class ExperimentController(object): rm = self.get_resource(guid) return rm.start() + def get_start_time(self, guid): + """ Returns the start time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.start_time + + def get_stop_time(self, guid): + """ Returns the stop time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.stop_time + + def get_discover_time(self, guid): + """ Returns the discover time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.discover_time + + def get_provision_time(self, guid): + """ Returns the provision time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.provision_time + + def get_ready_time(self, guid): + """ Returns the deployment time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.ready_time + + def get_release_time(self, guid): + """ Returns the release time of the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.release_time + + def get_failed_time(self, guid): + """ Returns the time failure occured for the RM as a timestamp """ + rm = self.get_resource(guid) + return rm.failed_time + def set_with_conditions(self, name, value, guids1, guids2, state, time = None): - """ Set value 'value' on attribute with name 'name' on all RMs of - guids1 when 'time' has elapsed since all elements in guids2 - have reached state 'state'. + """ Modifies the value of attribute with name 'name' on all RMs + on the guids1 list when time 'time' has elapsed since all + elements in guids2 list have reached state 'state'. :param name: Name of attribute to set in RM :type name: string @@ -605,17 +783,20 @@ class ExperimentController(object): rm.set_with_conditions(name, value, guids2, state, time) def deploy(self, guids = None, wait_all_ready = True, group = None): - """ Deploy all resource manager in guids list + """ Deploys all ResourceManagers in the guids list. + + If the argument 'guids' is not given, all RMs with state NEW + are deployed. - :param guids: List of guids of RMs to deploy - :type guids: 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 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 + :param group: Id of deployment group in which to deploy RMs + :type group: int """ self.logger.debug(" ------- DEPLOY START ------ ") @@ -623,8 +804,8 @@ class ExperimentController(object): if not guids: # If no guids list was passed, all 'NEW' RMs will be deployed guids = [] - for guid in self.resources: - if self.state(guid) == ResourceState.NEW: + for guid, rm in self._resources.iteritems(): + if rm.state == ResourceState.NEW: guids.append(guid) if isinstance(guids, int): @@ -656,7 +837,6 @@ class ExperimentController(object): break if reschedule: - callback = functools.partial(wait_all_and_start, group) self.schedule("1s", callback) else: @@ -665,6 +845,11 @@ class ExperimentController(object): rm = self.get_resource(guid) self.schedule("0s", rm.start_with_conditions) + 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("0s", rm.stop_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. @@ -683,43 +868,52 @@ class ExperimentController(object): if not wait_all_ready: self.schedule("0s", rm.start_with_conditions) - 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("0s", rm.stop_with_conditions) + 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("0s", rm.stop_with_conditions) def release(self, guids = None): - """ Release al RMs on the guids list or - all the resources if no list is specified + """ Releases all ResourceManagers in the guids list. + + If the argument 'guids' is not given, all RMs registered + in the experiment are released. :param guids: List of RM guids :type guids: list """ + if isinstance(guids, int): + guids = [guids] + if not guids: guids = self.resources - # Remove all pending tasks from the scheduler queue - for tid in list(self._scheduler.pending): - self._scheduler.remove(tid) - - self._runner.empty() - for guid in guids: rm = self.get_resource(guid) self.schedule("0s", rm.release) self.wait_released(guids) + + for guid in guids: + if self.get(guid, "hardRelease"): + self.remove_resource(guid) def shutdown(self): - """ Shutdown the Experiment Controller. - Releases all the resources and stops task processing thread + """ Releases all resources and stops the ExperimentController """ # If there was a major failure we can't exit gracefully if self._state == ECState.FAILED: raise RuntimeError("EC failure. Can not exit gracefully") + # Remove all pending tasks from the scheduler queue + for tid in list(self._scheduler.pending): + self._scheduler.remove(tid) + + # Remove pending tasks from the workers queue + self._runner.empty() + self.release() # Mark the EC state as TERMINATED @@ -735,7 +929,7 @@ class ExperimentController(object): self._thread.join() def schedule(self, date, callback, track = False): - """ Schedule a callback to be executed at time date. + """ Schedules a callback to be executed at time 'date'. :param date: string containing execution time for the task. It can be expressed as an absolute time, using @@ -746,10 +940,12 @@ class ExperimentController(object): Python function, and receives args and kwargs as arguments. - :param track: if set to True, the task will be retrivable with + :param track: if set to True, the task will be retrievable with the get_task() method :return : The Id of the task + :rtype: int + """ timestamp = stabsformat(date) task = Task(timestamp, callback) @@ -767,37 +963,40 @@ class ExperimentController(object): """ 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. + Tasks are scheduled by invoking the schedule method with a target + callback and an execution time. + The schedule method creates a new Task object with that callback + and execution time, and pushes it into the '_scheduler' queue. + The execution time and the order of arrival of tasks are used + to order the tasks in the queue. + + The _process method is executed in an independent thread held by + the ExperimentController for as long as the experiment is running. + This method takes tasks from the '_scheduler' queue in a loop + and processes them 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. + the number of threads used to process tasks. The default value is + 50. + + To execute tasks in parallel, a ParallelRunner (PR) object is used. + This object keeps a pool of threads (workers), and a queue of tasks + scheduled for 'immediate' execution. + + On each iteration, the '_process' loop will take the next task that + is scheduled for 'future' execution from the '_scheduler' queue, + and if the execution time of that task is >= to the current time, + it will push that task into the PR for 'immediate execution'. + As soon as a worker is free, the PR will assign the next task to + that worker. + + Upon receiving a task to execute, each PR worker (thread) will + invoke the _execute method of the EC, passing the task as + argument. + The _execute method will then invoke 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 task will be marked as failed. """ @@ -855,18 +1054,11 @@ class ExperimentController(object): :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 - try: + # Invoke callback task.result = task.callback() + task.status = TaskStatus.DONE except: import traceback err = traceback.format_exc() @@ -876,8 +1068,9 @@ class ExperimentController(object): self.logger.error("Error occurred while executing task: %s" % err) def _notify(self): - """ Awakes the processing thread in case it is blocked waiting - for a new task to be scheduled. + """ Awakes the processing thread if it is blocked waiting + for new tasks to arrive + """ self._cond.acquire() self._cond.notify()