XSConsoleTask.py

# Copyright (c) 2007-2009 Citrix Systems Inc.
#
# 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; version 2 only.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

from XSConsoleAuth import *
from XSConsoleBases import *
from XSConsoleHotData import *

class TaskEntry:
    def __init__(self, inHotOpaqueRef, inSession):
        self.hotOpaqueRef = inHotOpaqueRef
        self.session = inSession
        self.startTime = time.time()
        self.completed = False
        self.creationTime = None
        self.finishTime = None
        self.result = None

    def Completed(self):
        return self.completed

    def HandleCompletion(self, inStatus):
        if self.completed:
            raise Exception('TaskEntry.HandleCompletion called more than once')
        self.completed = True
        self.completionStatus = inStatus

        self.creationTime = TimeUtils.DateTimeToSecs(self.session.xenapi.task.get_created(self.hotOpaqueRef.OpaqueRef()))
        self.finishTime = TimeUtils.DateTimeToSecs(self.session.xenapi.task.get_finished(self.hotOpaqueRef.OpaqueRef()))
        if inStatus.startswith('success'):
            result = self.session.xenapi.task.get_result(self.hotOpaqueRef.OpaqueRef())
            result = result.replace("<value>", "").replace("</value>", "")
            self.result = HotOpaqueRef(result, 'any')
        if inStatus.startswith('failure'):
            self.errorInfo = self.session.xenapi.task.get_error_info(self.hotOpaqueRef.OpaqueRef())

        Auth.Inst().CloseSession(self.session)
        self.session = None

    def Status(self):
        if self.Completed():
            status = self.completionStatus
        else:
            status = self.session.xenapi.task.get_status(self.hotOpaqueRef.OpaqueRef())
            if not status.startswith('pending'):
                self.HandleCompletion(status)
        return status

    def Result(self):
        return self.result

    def CanCancel(self):
        if self.Completed():
            retVal = False
        else:
            allowedOps = self.session.xenapi.task.get_allowed_operations(self.hotOpaqueRef.OpaqueRef())
            retVal = ('cancel' in allowedOps)

        return retVal

    def Message(self):
        status = self.Status().lower()
        if status.startswith('pending'):
            retVal = Lang('In progress')
        elif status.startswith('success'):
            retVal = Lang('Operation was successful')
        elif status.startswith('failure'):
            retVal = Lang('Failed: ')+Language.XapiError(self.errorInfo)
        elif status.startswith('cancelling'):
            retVal = Lang('Cancellation in progress')
        elif status.startswith('cancelled'):
            retVal = Lang('Cancelled')
        else:
            retVal = Lang('<Unknown>')

        return retVal

    def RaiseIfFailed(self):
        if self.Status().lower().startswith('failure'):
            raise Exception(Language.XapiError(self.errorInfo))

    def IsPending(self):
        if self.Status().lower().startswith('pending'):
            retVal = True
        else:
            retVal = False
        return retVal

    def ProgressValue(self):
        if self.Completed():
            retVal = 1.0
        else:
            retVal = self.session.xenapi.task.get_progress(self.hotOpaqueRef.OpaqueRef())
        return retVal

    def DurationSecs(self):
        if self.creationTime is not None and self.finishTime is not None:
            retVal = self.finishTime - self.creationTime
        else:
            retVal = time.time() - self.startTime
        return retVal

    def Cancel(self):
        if not self.completed:
            self.session.xenapi.task.cancel(self.hotOpaqueRef.OpaqueRef())

class Task:
    instance = None
    def __init__(self):
        self.taskList = {}
        self.syncSession = None

    @classmethod
    def Inst(cls):
        if cls.instance is None:
            cls.instance = Task()
        return cls.instance

    def Create(self, inProc):
        session = None
        try:
            session = Auth.Inst().NewSession()
            taskRef = inProc(session)
        except:
            if session is not None:
                Auth.Inst().CloseSession(session)
            raise

        hotTaskRef = HotOpaqueRef(taskRef, 'task')
        taskEntry = TaskEntry(hotTaskRef, session)
        self.taskList[hotTaskRef] = taskEntry
        return taskEntry

    def GarbageCollect(self):
        # This may be expensive as it must fetch status from xapi for each incomplete task
        deleteKeys = []
        for key, value in self.taskList.items():
            # Forget tasks that have of duration of greater than one day
            value.Status()
            if value.Completed() or value.DurationSecs() > 86400:
                deleteKeys.append(key)

        for key in deleteKeys:
            del self.taskList[key]

    def SyncSession(self):
        if self.syncSession is None:
            self.syncSession = Auth.Inst().NewSession()
        return self.syncSession

    def SyncOperation(self, inProc):
        retVal = inProc(self.SyncSession())
        return retVal

    @classmethod
    def New(cls, inProc):
        return cls.Inst().Create(inProc)

    @classmethod
    def Sync(cls, inProc):
        return cls.Inst().SyncOperation(inProc)