filter json via bash - case insensitive - bash

Question

I have json code and need to filter it by the value of the attribute DNSName. The filter must be case insensitive.
How can I do that? Is there a possibility to solve it with jq?
This is how I create the json code:
aws elbv2 describe-load-balancers --region=us-west-2 | jq
My unfiltered source json code looks like this:
{
"LoadBalancers": [
{
"IpAddressType": "ipv4",
"VpcId": "vpc-abcdabcd",
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:000000000000:loadbalancer/app/MY-LB1/a00000000000000a",
"State": {
"Code": "active"
},
"DNSName": "MY-LB1-123454321.us-west-2.elb.amazonaws.com",
"SecurityGroups": [
"sg-00100100",
"sg-01001000",
"sg-10010001"
],
"LoadBalancerName": "MY-LB1",
"CreatedTime": "2018-01-01T00:00:00.000Z",
"Scheme": "internet-facing",
"Type": "application",
"CanonicalHostedZoneId": "ZZZZZZZZZZZZZ",
"AvailabilityZones": [
{
"SubnetId": "subnet-17171717",
"ZoneName": "us-west-2a"
},
{
"SubnetId": "subnet-27272727",
"ZoneName": "us-west-2c"
},
{
"SubnetId": "subnet-37373737",
"ZoneName": "us-west-2b"
}
]
},
{
"IpAddressType": "ipv4",
"VpcId": "vpc-abcdabcd",
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:000000000000:loadbalancer/app/MY-LB2/b00000000000000b",
"State": {
"Code": "active"
},
"DNSName": "MY-LB2-9876556789.us-west-2.elb.amazonaws.com",
"SecurityGroups": [
"sg-88818881"
],
"LoadBalancerName": "MY-LB2",
"CreatedTime": "2018-01-01T00:00:00.000Z",
"Scheme": "internet-facing",
"Type": "application",
"CanonicalHostedZoneId": "ZZZZZZZZZZZZZ",
"AvailabilityZones": [
{
"SubnetId": "subnet-54545454",
"ZoneName": "us-west-2a"
},
{
"SubnetId": "subnet-64646464",
"ZoneName": "us-west-2c"
},
{
"SubnetId": "subnet-74747474",
"ZoneName": "us-west-2b"
}
]
}
]
}
I now want some bash code to filter this result for the record with the DNSName property value MY-LB2-9876556789.us-west-2.elb.amazonaws.com, and need the entire LoadBalancer object back as a result. This is how I wish my result to look like:
{
"IpAddressType": "ipv4",
"VpcId": "vpc-abcdabcd",
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-west-2:000000000000:loadbalancer/app/MY-LB2/b00000000000000b",
"State": {
"Code": "active"
},
"DNSName": "MY-LB2-9876556789.us-west-2.elb.amazonaws.com",
"SecurityGroups": [
"sg-88818881"
],
"LoadBalancerName": "MY-LB2",
"CreatedTime": "2018-01-01T00:00:00.000Z",
"Scheme": "internet-facing",
"Type": "application",
"CanonicalHostedZoneId": "ZZZZZZZZZZZZZ",
"AvailabilityZones": [
{
"SubnetId": "subnet-54545454",
"ZoneName": "us-west-2a"
},
{
"SubnetId": "subnet-64646464",
"ZoneName": "us-west-2c"
},
{
"SubnetId": "subnet-74747474",
"ZoneName": "us-west-2b"
}
]
}
Does anyone know how to do it?
Update:
This solution works, but is not case insensitive:
aws elbv2 describe-load-balancers --region=us-west-2 | jq -c '.LoadBalancers[] | select(.DNSName | contains("MY-LB2"))'
Update:
This solution seems to work even better:
aws elbv2 describe-load-balancers --region=us-west-2 | jq -c '.LoadBalancers[] | select(.DNSName | match("my-lb2";"i"))'
But I did not have the chance to test in detail yet.

Answer 1

You probably should be using test/2 rather than match/2, but in either case, since the problem description calls for
case-insensitive equality, you would use an anchored regex:
.LoadBalancers[]
| select(.DNSName | test("^my-lb2-9876556789.us-west-2.elb.amazonaws.com$";"i"))
With the caveat that ascii_upcase only translates ASCII characters, it might be more efficient to use it:
.LoadBalancers[]
| select(.DNSName | ascii_upcase == "MY-LB2-9876556789.US-WEST-2.ELB.AMAZONAWS.COM")