Coverage for nova/virt/event.py: 97%

1# Copyright 2013 Red Hat, Inc. 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); you may 

4# not use this file except in compliance with the License. You may obtain 

5# a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 

11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 

12# License for the specific language governing permissions and limitations 

13# under the License. 

14 

15""" 

16Asynchronous event notifications from virtualization drivers. 

17 

18This module defines a set of classes representing data for 

19various asynchronous events that can occur in a virtualization 

20driver. 

21""" 

22 

23import time 

24 

25from nova.i18n import _ 

26 

27EVENT_LIFECYCLE_STARTED = 0 

28EVENT_LIFECYCLE_STOPPED = 1 

29EVENT_LIFECYCLE_PAUSED = 2 

30EVENT_LIFECYCLE_RESUMED = 3 

31EVENT_LIFECYCLE_SUSPENDED = 4 

32EVENT_LIFECYCLE_POSTCOPY_STARTED = 5 

33EVENT_LIFECYCLE_MIGRATION_COMPLETED = 6 

34 

35 

36NAMES = { 

37 EVENT_LIFECYCLE_STARTED: _('Started'), 

38 EVENT_LIFECYCLE_STOPPED: _('Stopped'), 

39 EVENT_LIFECYCLE_PAUSED: _('Paused'), 

40 EVENT_LIFECYCLE_RESUMED: _('Resumed'), 

41 EVENT_LIFECYCLE_SUSPENDED: _('Suspended'), 

42 EVENT_LIFECYCLE_POSTCOPY_STARTED: _('Postcopy started'), 

43 EVENT_LIFECYCLE_MIGRATION_COMPLETED: _('Migration completed'), 

44} 

45 

46 

47class Event(object): 

48 """Base class for all events emitted by a hypervisor. 

49 

50 All events emitted by a virtualization driver are 

51 subclasses of this base object. The only generic 

52 information recorded in the base class is a timestamp 

53 indicating when the event first occurred. The timestamp 

54 is recorded as fractional seconds since the UNIX epoch. 

55 """ 

56 

57 def __init__(self, timestamp=None): 

58 if timestamp is None: 

59 self.timestamp = time.time() 

60 else: 

61 self.timestamp = timestamp 

62 

63 def get_timestamp(self): 

64 return self.timestamp 

65 

66 def __repr__(self): 

67 return "<%s: %s>" % ( 

68 self.__class__.__name__, 

69 self.timestamp) 

70 

71 

72class InstanceEvent(Event): 

73 """Base class for all instance events. 

74 

75 All events emitted by a virtualization driver which 

76 are associated with a virtual domain instance are 

77 subclasses of this base object. This object records 

78 the UUID associated with the instance. 

79 """ 

80 

81 def __init__(self, uuid, timestamp=None): 

82 super(InstanceEvent, self).__init__(timestamp) 

83 

84 self.uuid = uuid 

85 

86 def get_instance_uuid(self): 

87 return self.uuid 

88 

89 def __repr__(self): 

90 return "<%s: %s, %s>" % ( 

91 self.__class__.__name__, 

92 self.timestamp, 

93 self.uuid) 

94 

95 

96class LifecycleEvent(InstanceEvent): 

97 """Class for instance lifecycle state change events. 

98 

99 When a virtual domain instance lifecycle state changes, 

100 events of this class are emitted. The EVENT_LIFECYCLE_XX 

101 constants defined why lifecycle change occurred. This 

102 event allows detection of an instance starting/stopping 

103 without need for polling. 

104 """ 

105 

106 def __init__(self, uuid, transition, timestamp=None): 

107 super(LifecycleEvent, self).__init__(uuid, timestamp) 

108 

109 self.transition = transition 

110 

111 def get_transition(self): 

112 return self.transition 

113 

114 def get_name(self): 

115 return NAMES.get(self.transition, _('Unknown')) 

116 

117 def __repr__(self): 

118 return "<%s: %s, %s => %s>" % ( 

119 self.__class__.__name__, 

120 self.timestamp, 

121 self.uuid, 

122 self.get_name())