| 50 |
50 |
"""Logical Unit base class.
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| 51 |
51 |
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| 52 |
52 |
Subclasses must follow these rules:
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| 53 |
|
- implement CheckPrereq which also fills in the opcode instance
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| 54 |
|
with all the fields (even if as None)
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53 |
- implement ExpandNames
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54 |
- implement CheckPrereq
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| 55 |
55 |
- implement Exec
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| 56 |
56 |
- implement BuildHooksEnv
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| 57 |
57 |
- redefine HPATH and HTYPE
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| ... | ... | |
| 82 |
82 |
self.cfg = context.cfg
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| 83 |
83 |
self.sstore = sstore
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| 84 |
84 |
self.context = context
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|
85 |
self.needed_locks = None
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| 85 |
86 |
self.__ssh = None
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| 86 |
87 |
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| 87 |
88 |
for attr_name in self._OP_REQP:
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| ... | ... | |
| 109 |
110 |
|
| 110 |
111 |
ssh = property(fget=__GetSSH)
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| 111 |
112 |
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|
113 |
def ExpandNames(self):
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|
114 |
"""Expand names for this LU.
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|
115 |
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116 |
This method is called before starting to execute the opcode, and it should
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|
117 |
update all the parameters of the opcode to their canonical form (e.g. a
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118 |
short node name must be fully expanded after this method has successfully
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|
119 |
completed). This way locking, hooks, logging, ecc. can work correctly.
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|
120 |
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121 |
LUs which implement this method must also populate the self.needed_locks
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122 |
member, as a dict with lock levels as keys, and a list of needed lock names
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123 |
as values. Rules:
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|
124 |
- Use an empty dict if you don't need any lock
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125 |
- If you don't need any lock at a particular level omit that level
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|
126 |
- Don't put anything for the BGL level
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127 |
- If you want all locks at a level use None as a value
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128 |
(this reflects what LockSet does, and will be replaced before
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|
129 |
CheckPrereq with the full list of nodes that have been locked)
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130 |
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131 |
Examples:
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132 |
# Acquire all nodes and one instance
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133 |
self.needed_locks = {
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134 |
locking.LEVEL_NODE: None,
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135 |
locking.LEVEL_INSTANCES: ['instance1.example.tld'],
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|
136 |
}
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137 |
# Acquire just two nodes
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138 |
self.needed_locks = {
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139 |
locking.LEVEL_NODE: ['node1.example.tld', 'node2.example.tld'],
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|
140 |
}
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|
141 |
# Acquire no locks
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|
142 |
self.needed_locks = {} # No, you can't leave it to the default value None
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|
143 |
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|
144 |
"""
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145 |
# The implementation of this method is mandatory only if the new LU is
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|
146 |
# concurrent, so that old LUs don't need to be changed all at the same
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|
147 |
# time.
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|
148 |
if self.REQ_BGL:
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|
149 |
self.needed_locks = {} # Exclusive LUs don't need locks.
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|
150 |
else:
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|
151 |
raise NotImplementedError
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|
152 |
|
| 112 |
153 |
def CheckPrereq(self):
|
| 113 |
154 |
"""Check prerequisites for this LU.
|
| 114 |
155 |
|
| ... | ... | |
| 121 |
162 |
not fulfilled. Its return value is ignored.
|
| 122 |
163 |
|
| 123 |
164 |
This method should also update all the parameters of the opcode to
|
| 124 |
|
their canonical form; e.g. a short node name must be fully
|
| 125 |
|
expanded after this method has successfully completed (so that
|
| 126 |
|
hooks, logging, etc. work correctly).
|
|
165 |
their canonical form if it hasn't been done by ExpandNames before.
|
| 127 |
166 |
|
| 128 |
167 |
"""
|
| 129 |
168 |
raise NotImplementedError
|