Source Code for Module pulp.server.tasking.queue.base

  1  #!/usr/bin/env python 
  2  # -*- coding: utf-8 -*- 
  3  # 
  4  # Copyright © 2010 Red Hat, Inc. 
  5  # 
  6  # This software is licensed to you under the GNU General Public License, 
  7  # version 2 (GPLv2). There is NO WARRANTY for this software, express or 
  8  # implied, including the implied warranties of MERCHANTABILITY or FITNESS 
  9  # FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2 
 10  # along with this software; if not, see 
 11  # http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt. 
 12  # 
 13  # Red Hat trademarks are not licensed under GPLv2. No permission is 
 14  # granted to use or replicate Red Hat trademarks that are incorporated 
 15  # in this software or its documentation. 
 16   
 17  import pulp.server.tasking.task 
 18   
 19   
 20  _task_complete_states = pulp.server.tasking.task.task_complete_states 
 21   
 22  # base task queue ------------------------------------------------------------- 
 23   
 24 -class TaskQueue(object): 
 25      """ 
 26      Abstract base class for task queues for interface definition and typing. 
 27      """ 
 28 -    def enqueue(self, task, unique=False): 
 29          """ 
 30          Add a task to the task queue 
 31          @type task: pulp.tasking.task.Task 
 32          @param task: Task instance 
 33          @type unique: bool 
 34          @param unique: If True, the task will only be added if there are no 
 35                         non-finished tasks with the same method_name, args, 
 36                         and kwargs; otherwise the task will always be added 
 37          @return: True if a new task was created; False if it was rejected (due to 
 38                   the unique flag 
 39          """ 
 40          raise NotImplementedError() 
 41   
 42 -    def run(self, task): 
 43          """ 
 44          Run a task from this task queue 
 45          @type task: pulp.tasking.task.Task 
 46          @param task: Task instance 
 47          """ 
 48          raise NotImplementedError() 
 49   
 50 -    def complete(self, task): 
 51          """ 
 52          Mark a task run as completed 
 53          @type task: pulp.tasking.task.Task 
 54          @param task: Task instance 
 55          """ 
 56          raise NotImplementedError() 
 57   
 58 -    def cancel(self, task): 
 59          """ 
 60          Cancel a running task. 
 61          @type task: pulp.tasking.task.Task 
 62          @param task: Task instance 
 63          """ 
 64          raise NotImplementedError() 
 65   
 66 -    def find(self, **kwargs): 
 67          """ 
 68          Find a task in this task queue. Only the oldest task in the queue will be 
 69          returned. 
 70          @type kwargs: dict 
 71          @param kwargs: task attributes and values as search criteria 
 72          @type include_finished: bool 
 73          @return: Task instance on success, None otherwise 
 74          """ 
 75          raise NotImplementedError() 
 76   
 77 -    def exists(self, task, criteria, include_finished=True): 
 78          """ 
 79          Returns whether or not the given task exists in this queue. The list 
 80          of which attributes that will be checked on the task for equality is 
 81          determined by the entries in the criteria list. 
 82   
 83          @type  task: Task instance 
 84          @param task: Values in this task will be used to test for this task's 
 85                       existence in the queue 
 86   
 87          @type  criteria: List; cannot be None 
 88          @param criteria: List of attribute names in the Task class; a task is 
 89                           considered equal to the given task if the values for 
 90                           all attributes listed in here are equal in an existing 
 91                           task in the queue 
 92   
 93          @type  include_finished: bool 
 94          @param include_finished: If True, finished tasks will be included in the search; 
 95                                   otherwise only running and waiting tasks are searched 
 96                                   (defaults to True) 
 97          """ 
 98   
 99          # Convert the list of attributes to check into a criteria dict used 
100          # by the storage API, using the task to test as the values 
101          find_criteria = {} 
102          for attr_name in criteria: 
103              if not hasattr(task, attr_name): 
104                  raise ValueError('Task has no attribute named [%s]' % attr_name) 
105              find_criteria[attr_name] = getattr(task, attr_name) 
106   
107          # Use the find functionality to determine if a task matches 
108          task = self.find(**find_criteria) 
109          if task is None or (not include_finished and 
110                              task.state in _task_complete_states): 
111              return False 
112          return True 
113