Filtering out Json with jmespath

Question

I have this simple Python script, it is supposed to be part of something bigger I just cannot figure out how to work with jmespath

#!/usr/bin/env python

import jmespath

if __name__ == '__main__':
# input json
text = \
{
    'topology': [
        {
            'node': [
                {
                    'topology-stats:session-state': {
                        'synchronized': True,
                        'local-pref': {
                            'session-id': 0,
                            'deadtimer': 120,
                            'ip-address': '10.30.170.187',
                            'keepalive': 30
                        },
                        'messages': {
                            'stateful-stats:sent-upd-msg-count': 1,
                            'last-sent-msg-timestamp': 1513334157,
                            'stateful-stats:last-received-rpt-msg-timestamp': 1513334157,
                            'unknown-msg-received': 0,
                            'stateful-stats:received-rpt-msg-count': 3,
                            'reply-time': {
                                'max-time': 77,
                                'average-time': 77,
                                'min-time': 77
                            },
                            'stateful-stats:sent-init-msg-count': 0,
                            'sent-msg-count': 1,
                            'received-msg-count': 3
                        },
                        'session-duration': '0:00:00:12'
                    },
                    'node-id': '10.30.170.117'
                }
            ],
            'topology-id': 'asdf-topology'
        }
    ]
}

exp = jmespath.compile('''topology[*].node[?'topology-stats:session-state' != 'session-duration'][]''')
result = exp.search(text)

print result

What I want is to basically remove lines with keys which have unpredictable values ( in perfect world I would switch the value for something generic ) - like: last-sent-msg-timestamp, session-duration, stateful-stats:last-received-rpt-msg-timestamp. And perfectly I would want to keep everything else, although I can live with loosing topology and node tags.

The thing is I can use only one jmespath.search and I can do only one jmespath expression. Also I cannot use anything else from Python - this script is just example.

Is this possible with jmespath? It is currently my best option due to limitations of project.

The question is do You have to use JMES for this? What You are trying to do would be much easier done using MongoDB or other no-sql document based engine. — Tetlanesh, Jan 04 '18 at 23:59

score 1 · Answer 1 · answered Apr 18 '18 at 11:00

Removing fields with Jmespath is not possible currently. There is a pending feature request:

Ability to set and delete based on a jmespath #121 https://github.com/jmespath/jmespath.py/issues/121

I am using jq to do that:

jq 'del(.foo)'
Input   {"foo": 42, "bar": 9001, "baz": 42}
Output  {"bar": 9001, "baz": 42}

Filtering out Json with jmespath

1 Answers1