Searching for object with jQ in command line - json

Question

I have a JSON file of AWS security groups list. I am trying to fetch the Group Id using the Group Name. The object looks like the following:
{
"SecurityGroups": [{
"IpPermissionsEgress": [
{
"IpProtocol": "-1",
}
],
"Description": "launch-wizard-2 created 2017-10-21T09:19:40.007-04:00",
"GroupName": "MY1SG-PUBLIC-80",
"VpcId": "vpc-ceed12b7",
"OwnerId": "712503525534",
"GroupId": "sg-ee0c979c"
}]
}
With jQ my attempt is as follows:
aws ec2 describe-security-groups | jq '.GroupId' ["GroupName": "MY1SG-PUBLIC-80"]
Error:
jq: error: Could not open file [GroupName:: No such file or directory
jq: error: Could not open file MY1SG-PUBLIC-80]: No such file or directory

Answer 1

Issue 1: Format
https://shapeshed.com/jq-json/
The second input to jq is the file you wish to read from. If this value is - the program will read from the instream.
Issue 2: Selection
https://stedolan.github.io/jq/manual/#select(boolean_expression)
To select an element by value you should/could use a select statement
select(.GroupName == "MY1SG-PUBLIC-80")
jq 'SCOPE | select(.GroupName == "MY1SG-PUBLIC-80") | .GroupId[]' -
where SCOPE is the group you wish to look in. if SCOPE is .[], it will scan every json entry. Following this, it pipes this group into a select filter, and trims it down to only ones that have GroupName set to the given value. This result set is then piped into a key filter, where it only returns the array of matching GroupID's.

Answer 2

I am trying to fetch the Group Id using the Group Name.
Assuming the input has been tweaked to make it valid JSON (*), the filter:
.SecurityGroups[] | select(.GroupName=="MY1SG-PUBLIC-80") | .GroupId
produces:
"sg-ee0c979c"
It might be worthwhile considering this alternative filter:
.[][]|select(.GroupName=="MY1SG-PUBLIC-80")|.GroupId
(*) The input as originally shown has an extraneous comma.