simple python snippet to print first level of json key names

json_keys.py

import json

fn='/opt/suricata/var/log/suricata/eve.json'
f=open(fn)
lines=f.readlines()
f.close()

u=dict()
for line in lines:
    try:
	j=json.loads(line)
	for key in j:
		if not key in u:
			u[key]=j[key]	
    except :
	pass

for k in u:
	print k, '|',u[k]