Source Code for Module ganeti.qlang

 1  # 
 2  # 
 3   
 4  # Copyright (C) 2010 Google Inc. 
 5  # 
 6  # This program is free software; you can redistribute it and/or modify 
 7  # it under the terms of the GNU General Public License as published by 
 8  # the Free Software Foundation; either version 2 of the License, or 
 9  # (at your option) any later version. 
10  # 
11  # This program is distributed in the hope that it will be useful, but 
12  # WITHOUT ANY WARRANTY; without even the implied warranty of 
13  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
14  # General Public License for more details. 
15  # 
16  # You should have received a copy of the GNU General Public License 
17  # along with this program; if not, write to the Free Software 
18  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
19  # 02110-1301, USA. 
20   
21   
22  """Module for a simple query language""" 
23   
24  from ganeti import errors 
25   
26   
27  OP_OR = "|" 
28  OP_EQUAL = "=" 
29   
30   
31 -def ReadSimpleFilter(namefield, filter_): 
32    """Function extracting wanted names from restricted filter. 
33   
34    This should only be used until proper filtering is implemented. The filter 
35    must either be empty or of the format C{["|", ["=", field, "name1"], ["=", 
36    field, "name2"], ...]}. 
37   
38    """ 
39    if filter_ is None: 
40      return [] 
41   
42    if not isinstance(filter_, list): 
43      raise errors.ParameterError("Filter should be list") 
44   
45    if not filter_ or filter_[0] != OP_OR: 
46      raise errors.ParameterError("Filter should start with OR operator") 
47   
48    if len(filter_) < 2: 
49      raise errors.ParameterError("Invalid filter, OR operator should have" 
50                                  " operands") 
51   
52    result = [] 
53   
54    for idx, item in enumerate(filter_[1:]): 
55      if not isinstance(item, list): 
56        raise errors.ParameterError("Invalid OR operator, operand %s not a" 
57                                    " list" % idx) 
58   
59      if len(item) != 3 or item[0] != OP_EQUAL: 
60        raise errors.ParameterError("Invalid OR operator, operand %s is not an" 
61                                    " equality filter" % idx) 
62   
63      (_, name, value) = item 
64   
65      if not isinstance(value, basestring): 
66        raise errors.ParameterError("Operand %s for OR should compare against a" 
67                                    " string" % idx) 
68   
69      if name != namefield: 
70        raise errors.ParameterError("Operand %s for OR should filter field '%s'," 
71                                    " not '%s'" % (idx, namefield, name)) 
72   
73      result.append(value) 
74   
75    return result 
76   
77   
78 -def MakeSimpleFilter(namefield, values): 
79    """Builds a filter for use with L{ReadSimpleFilter}. 
80   
81    @param namefield: Name of field containing item name 
82    @param values: List of names 
83   
84    """ 
85    if values: 
86      return [OP_OR] + [[OP_EQUAL, namefield, i] for i in values] 
87   
88    return None 
89