jq: search by value from another array element - jq

Question

I have an array of objects of various types which reference one another with UUIDs (a terraform.tfstate file). I'd like to select one value from one such object based on the appearance of a different value in another object, where the two objects are related by one of those UUIDs.
By way of example, I can do this:
$ jq '.modules[].resources[]
| select(.type == "openstack_compute_instance_v2" and
.primary.attributes.name == "jumpbox").primary.id' terraform.tfstate
"5edfe2bf-94df-49d5-8118-3e91fb52946b"
$ jq '.modules[].resources[]
| select(.type =="openstack_compute_floatingip_associate_v2" and
.primary.attributes.instance_id == "5edfe2bf-94df-49d5-8118-3e91fb52946b").primary.attributes.floating_ip' terraform.tfstate
"10.120.241.21"
Giving me the external floating IP of the 'jumpbox' VM based on its name.
I'd like to make that all one jq call. Is that possible?

Answer 1

This would be easier to answer if you provided more sample data but
working backwards from your commands (with some reformatting)
$ jq '
.modules[].resources[]
| select(.type == "openstack_compute_instance_v2" and .primary.attributes.name == "jumpbox")
| .primary.id
' terraform.tfstate
"5edfe2bf-94df-49d5-8118-3e91fb52946b"
$ jq '
.modules[].resources[]
| select(.type =="openstack_compute_floatingip_associate_v2" and .primary.attributes.instance_id == "5edfe2bf-94df-49d5-8118-3e91fb52946b")
| .primary.attributes.floating_ip
' terraform.tfstate
"10.120.241.21"
we can infer you have data which looks like
{
"modules": [
{
"resources": [
{
"type": "openstack_compute_instance_v2",
"primary": {
"id": "5edfe2bf-94df-49d5-8118-3e91fb52946b",
"attributes": {
"name": "jumpbox"
}
}
},
{
"type": "openstack_compute_floatingip_associate_v2",
"primary": {
"attributes": {
"instance_id": "5edfe2bf-94df-49d5-8118-3e91fb52946b",
"floating_ip": "10.120.241.21"
}
}
}
]
}
]
}
The following filter demonstrates a solution using functions, variables and parenthesis ():
def get_primary_id($name):
select(.type == "openstack_compute_instance_v2"
and .primary.attributes.name == $name)
| .primary.id
;
def get_floating_ip($id):
select(.type =="openstack_compute_floatingip_associate_v2"
and .primary.attributes.instance_id == $id)
| .primary.attributes.floating_ip
;
.modules[]
| ( .resources[] | get_primary_id("jumpbox") ) as $id
| ( .resources[] | get_floating_ip($id) ) as $fip
| ($id, $fip)
if this filter is in filter.jq and data.json contains the sample data above
then
$ jq -M -f filter.jq data.json
produces the output:
"5edfe2bf-94df-49d5-8118-3e91fb52946b"
"10.120.241.21"