Flatten JSON data with jq - jq

Question

I have output brakeman scan results to a json file and want to flatten the structure.
Brakeman json output sample looks like this
{
"scan_info": {
"security_warnings": 9,
"start_time": "2021-11-01 14:44:58 +1100",
"end_time": "2021-11-01 14:45:13 +1100",
"brakeman_version": "5.1.2"
},
"warnings": [
{
"warning_type": "Redirect",
"warning_code": 18,
"fingerprint": "cae2f2cfd8",
"check_name": "Redirect",
"message": "Possible unprotected redirect",
"file": "app/controllers/my/controller.rb",
"line": 24,
"link": "https://brakemanscanner.org/docs/warning_types/redirect/",
"code": "redirect_to....",
"render_path": null,
"location": {
"type": "method",
"class": "My::Controller",
"method": "request_token"
},
"user_input": "my.base_url",
"confidence": "High"
},
{.....}
],
"ignored_warnings": [],
"errors": [],
"obsolete": ["xxx","yyyy"]
}
I want to flatten the output into an array of objects similar to this. I want most data from the warnings array except .location and .render_path.
[
{
"brakeman_version": "5.1.2",
"warning_type": "Redirect",
"warning_code": 18,
"fingerprint": "cae2f0d2cfd8",
"check_name": "Redirect",
"message": "Possible unprotected redirect",
"line": 24,
"link": "https://brakemanscanner.org/docs/warning_types/redirect/",
"code": "redirect_to...",
"confidence": "High"
},
{
"brakeman_version": "5.1.2",
"warning_type": "SQL Injection",
"check_name": "SQL",
"message": "Possible SQL injection",
"warning_code": 35,
....
"confidence": "High"
}
]
Something like this gives a nested object for each item in the warnings array but I'd like to move them up a level
jq '{brakeman_version: .scan_info.brakeman_version, start_time: .scan_info.start_time, warnings: .warnings[]}' ./brakeman.json
Result
{
"brakeman_version": "5.1.2",
"start_time": "2021-11-01 14:44:58 +1100",
"warnings": {
"warning_type": "Redirect",
"warning_code": 18,
"fingerprint": "xxxx",
"check_name": "Redirect",
"message": "Possible unprotected redirect",
"line": 24,
"link": "https://brakemanscanner.org/docs/warning_types/redirect/",
"confidence": "High"
},
{...}
}
Something like this flattens the .scan_info part similarly but still leaves me with an array for warnings which is what was there in the first place.
jq '{
rails_version: .scan_info.rails_version,
security_warnings: .scan_info.security_warnings,
start_time: .scan_info.start_time,
brakeman_version: .scan_info.brakeman_version,
warnings: [.warnings[] | {warning_type: .warning_type,
warning_code: .warning_code,
fingerprint: .fingerprint,
check_name: .check_name,
confidence: .confidence} ],
obsolete: (.obsolete | join(",")),
}' ./brakeman.json
Results
{
"rails_version": "6.1.4.1",
"security_warnings": 9,
"start_time": "2021-11-01 14:44:58 +1100",
"warnings": [
{
"warning_type": "SQL Injection",
"warning_code": 0,
"fingerprint": "xx",
"check_name": "SQL",
"message": "Possible SQL injection",
"line": 178,
"link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
"confidence": "Medium"
},
{
"warning_type": "Format Validation",
"warning_code": 30,
"fingerprint": "xxx",
"check_name": "ValidationRegex",
"line": 92,
"link": "https://brakemanscanner.org/docs/warning_types/format_validation/",
"code": null,
"user_input": null,
"confidence": "High"
},
]
}
Using jq how do I correctly flatten the structure to output as desired?
I've tried some suggestions found on SO like
jq '{
rails_version: .scan_info.rails_version,
brakeman_version: .scan_info.brakeman_version,
.warnings[] as $in | $in | del(.location, .render_path) as $in2 | $in2,
obsolete: (.obsolete | join(",")),
}' ./brakeman.json
but have been going around in circles at this stage.

Answer 1

With assumptions based on your description provided, I guess you are looking to do this
.scan_info + ( .warnings[] | del(.location, .render_path) )
If you want the entire results packed into an array, enclose the above filter within square brackets([ ])
jqplay demo