Ceph » RADOS

When executing below command to get osd crush tree on Mimic version, it will output extra null list[] which makes json.loads(result) failed:
1. ceph osd crush tree --format=json-pretty
[ {
"id": -1,
"name": "default",
"type": "root",
"type_id": 10,
"children": []
}
]
[]

2. ceph osd crush tree --format=json
[{"id":-1,"name":"default","type":"root","type_id":10,"children":[]}][]

Example when doing json load example:

bug_str = '[{"id":-1,"name":"default","type":"root","type_id":10,"children":[]}][]'
json.loads(bug_str)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib64/python2.7/json/__init__.py", line 338, in loads
return _default_decoder.decode(s)
File "/usr/lib64/python2.7/json/decoder.py", line 369, in decode
raise ValueError(errmsg("Extra data", s, end, len(s)))
ValueError: Extra data: line 1 column 70 - line 1 column 72 (char 69 - 71)

good_str = '[{"id":-1,"name":"default","type":"root","type_id":10,"children":[]}]'
json.loads(good_str)

[{u'children': [], u'type_id': 10, u'type': u'root', u'id': -1, u'name': u'default'}]