vstf/vstf/agent/env/basic/image_manager.py

   1 ##############################################################################
   2 # Copyright (c) 2015 Huawei Technologies Co.,Ltd and others.
   3 #
   4 # All rights reserved. This program and the accompanying materials
   5 # are made available under the terms of the Apache License, Version 2.0
   6 # which accompanies this distribution, and is available at
   7 # http://www.apache.org/licenses/LICENSE-2.0
   8 ##############################################################################
   9
  10 from vstf.common.utils import check_call
  11 import os
  12 import logging
  13
  14 LOG = logging.getLogger(__name__)
  15
  16
  17 class _ImageManager(object):
  18     """
  19     A qemu-img wrapper to create qcow2 child image from a parent image.
  20
  21     """
  22     def __init__(self, parent_image_path, child_image_dir):
  23         """
  24         :param parent_image_path    str: the parent image path.
  25         :param child_image_dir      str: the destination path to put child images.
  26         """
  27         self._create_child_str = 'qemu-img create -f %(image_type)s %(child_path)s -o backing_file=%(parent_path)s'
  28         self._convert_str = "qemu-img convert -O %(image_type)s %(parent_path)s %(child_path)s"
  29         self.child_image_dir = child_image_dir
  30         self.parent_image_path = parent_image_path
  31         assert os.path.isfile(self.parent_image_path)
  32         assert os.path.isdir(self.child_image_dir)
  33
  34     def create_child_image(self, child_name, full_clone=False, image_type='qcow2'):
  35         """
  36         create a child image and put it in self.child_image_dir.
  37
  38         :param child_name:  the image name to be created..
  39         :return: return the path of child image.
  40         """
  41
  42         image_path = os.path.join(self.child_image_dir, child_name) + '.' + image_type
  43         if full_clone:
  44             cmd = self._convert_str % {'image_type': image_type, 'child_path': image_path, 'parent_path': self.parent_image_path}
  45         else:
  46             cmd = self._create_child_str % {'child_path': image_path, 'parent_path': self.parent_image_path, 'image_type':image_type}
  47         check_call(cmd.split())
  48         return image_path
  49
  50
  51 class ImageManager(object):
  52     def __init__(self, cfg):
  53         """
  54         ImageManager creates images from configuration context.
  55
  56         :param cfg: dict, example:
  57         {
  58             'parent_image': "/mnt/sdb/ubuntu_salt_master.img",
  59             'dst_location': "/mnt/sdb",
  60             'full_clone':False,
  61             'type': "qcow2",
  62             'names': ['vm1','vm2','vm3','vm4']
  63         }
  64         :return:
  65         """
  66         super(ImageManager, self).__init__()
  67         cfg = self._check_cfg(cfg)
  68         self.parent_image = cfg['parent_image']
  69         self.image_dir = cfg['dst_location']
  70         self.full_clone = cfg['full_clone']
  71         self.image_type = cfg['type']
  72         self.names = cfg['names']
  73         self.mgr = _ImageManager(self.parent_image, self.image_dir)
  74
  75     @staticmethod
  76     def _check_cfg(cfg):
  77         for key in ('parent_image', 'dst_location', 'full_clone', 'type', 'names'):
  78             if key not in cfg:
  79                 raise Exception("does't find %s config" % key)
  80         if cfg['type'] not in ('raw', 'qcow2'):
  81             raise Exception("type:%s not supported, only support 'raw' and 'qcow2'" % cfg['type'])
  82         if not cfg['full_clone'] and cfg['type'] == 'raw':
  83             raise Exception("only support 'qcow2' for not full_clone image creation" % cfg['type'])
  84         return cfg
  85
  86     def create_all(self):
  87         """
  88         create images by configuration context.
  89
  90         :return: True for success, False for failure.
  91         """
  92         for name in self.names:
  93             image = self.mgr.create_child_image(name, self.full_clone, self.image_type)
  94             LOG.info("image: %s created", image)
  95         return True
  96
  97     def clean_all(self):
  98         """
  99         remove all the images created in one go.
 100
 101         :return: True for success. Raise exception otherwise.
 102         """
 103         for name in self.names:
 104             image_path = os.path.join(self.image_dir, name + '.' + self.image_type)
 105             try:
 106                 os.unlink(image_path)
 107                 LOG.info("remove:%s successfully", image_path)
 108             except Exception:
 109                 LOG.info("cann't find path:%s", image_path)
 110         return True
 111
 112
 113 if __name__ == '__main__':
 114     import argparse
 115     import json
 116     parser = argparse.ArgumentParser()
 117     parser.add_argument('action', choices = ('create','clean'), help='action:create|clean')
 118     parser.add_argument('--config', help='config file to parse')
 119     args = parser.parse_args()
 120     logging.basicConfig(level=logging.INFO)
 121     image_cfg = json.load(open(args.config))
 122     mgr = ImageManager(image_cfg)
 123     if args.action == 'create':
 124         mgr.create_all()
 125     if args.action == 'clean':
 126         mgr.clean_all()
 127
 128