# 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):
+ """
+ .. class:: Class Args :
+
+ :param exp_id: Human readable identifier for the experiment.
+ It will be used in the name of the directory
+ where experiment related information is stored
+ :type exp_id: int
+
+ :param root_dir: Root directory where experiment specific folder
+ will be created to store experiment information
+ :type root_dir: str
+
+ .. note::
+ The ExperimentController (EC), is the entity responsible for
+ managing a single experiment.
+ Through the EC interface the user can create ResourceManagers (RMs),
+ configure them and interconnect them, in order to describe the experiment.
+
+ Only when the 'deploy()' method is invoked, 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.
+
+ """
+
def __init__(self, exp_id = None, root_dir = "/tmp"):
super(ExperimentController, self).__init__()
# root directory to store files
@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):
+ """ Return the experiment ID
+
+ """
exp_id = self._exp_id
if not exp_id.startswith("nepi-"):
exp_id = "nepi-" + exp_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) in [ResourceState.FINISHED,
- ResourceState.STOPPED,
- ResourceState.FAILED] \
- for guid in guids]) and not self.finished:
- # We keep the sleep as large as possible to
- # decrese the number of RM state requests
+ """ Blocking method that wait until all the RM from the 'guid' list
+ reached the state FINISHED
+
+ :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
+
+ :param guids: List of guids
+ :type guids: list
+ """
+ return self.wait(guids, states = [ResourceState.STARTED, ResourceState.FINISHED])
+
+ def wait(self, guids, states = [ResourceState.FINISHED]):
+ """ 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]
+
+ while not all([self.state(guid) in states for guid in guids]) and \
+ not any([self.state(guid) in [
+ ResourceState.STOPPED,
+ ResourceState.FAILED] for guid in guids]) and \
+ not self.finished:
+ # We keep the sleep big to decrease the number of RM state queries
time.sleep(2)
-
+
def get_task(self, tid):
+ """ Get a specific task
+
+ :param tid: Id of the task
+ :type tid: int
+ :rtype: unknow
+ """
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):
+ """ Return all the attibutes of a specific RM
+
+ :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 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)
return rm.trace(name, attr, block, offset)
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()
def provision(self, guid):
+ """ Provision a specific RM defined by its 'guid'
+
+ :param guid: Guid of the RM
+ :type guid: int
+
+ """
rm = self.get_resource(guid)
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)
return rm.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()
rm.set_with_conditions(name, value, group2, 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()
self.logger.debug(" ------- DEPLOY START ------ ")
if not group:
- group = self.resources
+ # By default, if not deployment group is indicated,
+ # all RMs that are undeployed will be deployed
+ group = []
+ for guid in self.resources:
+ if self.state(guid) == ResourceState.NEW:
+ group.append(guid)
+
+ if isinstance(group, int):
+ group = [group]
# Before starting deployment we disorder the group list with the
# purpose of speeding up the whole deployment process.
# 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 group list, this problem can be mitigated.
- random.shuffle(group)
+ #random.shuffle(group)
def wait_all_and_start(group):
reschedule = False
# If all resources are read, we schedule the start
for guid in group:
rm = self.get_resource(guid)
- self.schedule("0.01s", rm.start_with_conditions)
+ self.schedule("0s", rm.start_with_conditions)
if wait_all_ready:
# Schedule the function that will check all resources are
for guid in group:
rm = self.get_resource(guid)
- self.schedule("0.001s", rm.deploy)
+ self.schedule("0s", rm.deploy)
if not wait_all_ready:
self.schedule("1s", rm.start_with_conditions)
def release(self, group = None):
+ """ Release the elements of the list 'group' or
+ all the resources if any group is specified
+
+ :param group: List of RM
+ :type group: list
+
+ """
if not group:
group = self.resources
threads.remove(thread)
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)
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.
+
+ 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:
self._logger.error("Error while processing tasks in the EC: %s" % err)
self._state = ECState.FAILED
-
- # Mark EC state as terminated
- if self.ecstate == ECState.RUNNING:
- # Synchronize to get errors if occurred
+ finally:
+ self._logger.info("Exiting the task processing loop ... ")
runner.sync()
- self._state = ECState.TERMINATED
def _execute(self, task):
+ """ Executes a single task.
+
+ 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.
+
+ :param task: Object containing the callback to execute
+ :type task: Task
+
+ """
# Invoke callback
task.status = TaskStatus.DONE
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