Python 2.7: Generate JSON file with multiple query results in nested dict - json

Question

What started as my personal initiative, ended up being a quiet interesting ( may I say, challenging to some degree) project. My company decided to phase out one product and replace it with new one, which instead of storing data in mdb files, uses JSON files. So I took the initiative to create a converter that will read already created mdb files and convert them into the new format JSON.
However, now I'm at wits-ends with this one:
I can read mdb files, run query to extract specific data.
By placing the targetobj inside the FOR LOOP, I managed to extract data for each row and fed into a dict(targetobj)
for val in rows:
targetobj={"connection_props": {"port": 7800, "service": "", "host": val.Hostname, "pwd": "", "username": ""},
"group_list": val.Groups, "cpu_core_cnt": 2, "target_name": "somename", "target_type": "somethingsamething",
"os": val.OS, "rule_list": [], "user_list": val.Users}
if I print targetobj to console, I can clearly get all extracted values for each row.
Now, my quest is to have the obtained results ( for each row), inserted into the main_dict under the key targets:[]. ( Please see sample of JSON file for illustration)
main_dict = {"changed_time": 0, "year": 0, "description": 'blahblahblah', 'targets':[RESULTS FROM TARGETOBJ SHOULD BE ADDED HERE],"enabled": False}
so for example my Json file should have structure such as:
{"changed_time":1234556,
"year":0,
"description":"blahblahblah",
"targets":[
{"group_list":["QA"],
"cpu_core_cnt":1,
"target_name":"NewTarget",
"os":"unix",
"target_type":"",
"rule_list":[],
"user_list":[""],"connection_props":"port":someport,"service":"","host":"host1","pwd":"","username":""}
},
{"group_list":[],
"cpu_core_cnt":2,
"target_name":"",
"os":"unix",
"target_type":"",
"rule_list":[],
"user_list":["Web2user"],
"connection_props":{"port":anotherport,"service":"","host":"host2","pwd":"","username":""}}
],
"enabled":false}
So far I've been tweaking here and there, to have the results written as intended, however each time,I'm getting only the last row values written.
ie.: putting the targetobj as a variable inside the targets:[]
{"changed_time": 0, "year": 0, "description": 'ConvertedConfigFile', 'targets':[targetobj],
I know I'm missing something, I just need to find what and where.
Any help would be highly appreciated.
thank you

Answer 1

Just create your main_dict first and append to it in your loop, i.e.:
main_dict = {"changed_time": 0,
"year": 0,
"description": "blahblahblah",
"targets": [], # a new list for the target objects
"enabled": False}
for val in rows:
main_dict["targets"].append({ # append this dict to the targets list of main_dict
"connection_props": {
"port": 7800,
"service": "",
"host": val.Hostname,
"pwd": "",
"username": ""},
"group_list": val.Groups,
"cpu_core_cnt": 2,
"target_name": "somename",
"target_type": "somethingsamething",
"os": val.OS,
"rule_list": [],
"user_list": val.Users
})