Python class method

Question

I have a class instance of type <class 'openstack_dashboard.api.nova.Server'>:

 >>>print instance
 >>><Server: {'id': u'9fa3b2e9-a76b-44ae-be75-968d4010eb27', 
              'links': [{u'href': u'http://10.0.3.129:8774/v2/344f7fa036fc45008130cdf1cffac019/servers/9fa3b2e9-a76b-44ae-be75-968d4010eb27', u'rel': u'self'}, 
                        {u'href': u'http://10.0.3.129:8774/344f7fa036fc45008130cdf1cffac019/servers/9fa3b2e9-a76b-44ae-be75-968d4010eb27', u'rel': u'bookmark'}]}>
 >>> print dir(instance)
 >>> ['__class__', '__delattr__', '__dict__', '__doc__', '__format__', 
      '__getattr__', '__getattribute__', '__hash__', '__init__', 
      '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', 
      '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 
      '__weakref__', '_apiresource', '_attrs', 'image_name', 
      'internal_name', 'request']

I want to get the 'id' ('9fa3b2e9-a76b-44ae-be75-968d4010eb27'). What should I do ? Thank you !

Answer 1

According to what I can see in the source, Server inherits from the common APIResourceWrapper, which in turn implements __gatattr__ so that id, while it's not exactly an object's own attribute, will be taken from the internal container self._apiresource.

So, instance.id will work and will effectively return instance._apiresource.id.

Answer 2

Class openstack_dashboard.api.nova.Server inherits from openstack_dashboard.api.base.APIResourceWrapper and this class has defined __getattr__() method which uses self._attrs, so I think it should be possible to read id in this way:

print(instance.id)

Answer 3

This might work now for you, but it's implementation-dependent:

import re
printed = instance.__str__() #might also be __repr__()
m = re.search("'id'\s*:\s*u'([\w+\-]+)'", printed)
m.groups(0)[0] #returns 9fa3b2e9-a76b-44ae-be75-968d4010eb27