Examples¶
IOT lightbulb¶
Note
Full source located at iot_bulb.
1
2from datetime import datetime
3
4from oslo_versionedobjects import base
5from oslo_versionedobjects import fields as obj_fields
6
7# INTRO: This example shows how a object (a plain-old-python-object) with
8# some associated fields can be used, and some of its built-in methods can
9# be used to convert that object into a primitive and back again (as well
10# as determine simple changes on it.
11
12
13# Ensure that we always register our object with an object registry,
14# so that it can be deserialized from its primitive form.
15@base.VersionedObjectRegistry.register
16class IOTLightbulb(base.VersionedObject):
17 """Simple light bulb class with some data about it."""
18
19 VERSION = '1.0' # Initial version
20
21 #: Namespace these examples will use.
22 OBJ_PROJECT_NAMESPACE = 'versionedobjects.examples'
23
24 #: Required fields this object **must** declare.
25 fields = {
26 'serial': obj_fields.StringField(),
27 'manufactured_on': obj_fields.DateTimeField(),
28 }
29
30
31# Now do some basic operations on a light bulb.
32bulb = IOTLightbulb(serial='abc-123', manufactured_on=datetime.now())
33print("The __str__() output of this new object: %s" % bulb)
34print("The 'serial' field of the object: %s" % bulb.serial)
35bulb_prim = bulb.obj_to_primitive()
36print("Primitive representation of this object: %s" % bulb_prim)
37
38# Now convert the primitive back to an object (isn't it easy!)
39bulb = IOTLightbulb.obj_from_primitive(bulb_prim)
40
41bulb.obj_reset_changes()
42print("The __str__() output of this new (reconstructed)"
43 " object: %s" % bulb)
44
45# Mutating a field and showing what changed.
46bulb.serial = 'abc-124'
47print("After serial number change, the set of fields that"
48 " have been mutated is: %s" % bulb.obj_what_changed())
Expected (or similar) output:
The __str__() output of this new object: IOTLightbulb(manufactured_on=2017-03-15T23:25:01Z,serial='abc-123')
The 'serial' field of the object: abc-123
Primitive representation of this object: {'versioned_object.version': '1.0', 'versioned_object.changes': ['serial', 'manufactured_on'], 'versioned_object.name': 'IOTLightbulb', 'versioned_object.data': {'serial': u'abc-123', 'manufactured_on': '2017-03-15T23:25:01Z'}, 'versioned_object.namespace': 'versionedobjects.examples'}
The __str__() output of this new (reconstructed) object: IOTLightbulb(manufactured_on=2017-03-15T23:25:01Z,serial='abc-123')
After serial number change, the set of fields that have been mutated is: set(['serial'])
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