JQ Select Outer Objects and Child Based on Child - json

Question

I am trying to select the credentials object and specific parent level objects only if the key credhub-ref exist within the credential object following JSON:
{
"total_results": 23,
"total_pages": 1,
"prev_url": null,
"next_url": null,
"resources": [
{
"metadata": {
"guid": "cd",
"url": "/v2/service_bindings/cd",
"created_at": "2019-03-04T21:18:53Z",
"updated_at": "2019-03-04T21:18:53Z"
},
"entity": {
"app_guid": "9c",
"service_instance_guid": "66",
"credentials": {
"credhub-ref": "/c/54"
},
"binding_options": {},
"gateway_data": null,
"gateway_name": "",
"syslog_drain_url": null,
"volume_mounts": [],
"name": null,
"last_operation": {
"type": "create",
"state": "succeeded",
"description": "",
"updated_at": "2019-03-04T21:18:53Z",
"created_at": "2019-03-04T21:18:53Z"
},
"app_url": "/v2/apps/9c",
"service_instance_url": "/v2/service_instances/66",
"service_binding_parameters_url": "/v2/service_bindings/cd"
}
},
{
"metadata": {
"guid": "cd",
"url": "/v2/service_bindings/cd",
"created_at": "2019-03-11T08:49:22Z",
"updated_at": "2019-03-11T08:49:22Z"
},
"entity": {
"app_guid": "ea",
"service_instance_guid": "86",
"credentials": {},
"binding_options": {},
"gateway_data": null,
"gateway_name": "",
"syslog_drain_url": null,
"volume_mounts": [],
"name": null,
"last_operation": {
"type": "create",
"state": "succeeded",
"description": "",
"updated_at": "2019-03-11T08:49:22Z",
"created_at": "2019-03-11T08:49:22Z"
},
"app_url": "/v2/apps/ea",
"service_instance_url": "/v2/service_instances/86",
"service_binding_parameters_url": "/v2/service_bindings/cd"
}
},
{
"metadata": {
"guid": "e0",
"url": "/v2/service_bindings/e0",
"created_at": "2019-03-19T20:07:25Z",
"updated_at": "2019-03-19T20:07:25Z"
},
"entity": {
"app_guid": "73",
"service_instance_guid": "52",
"credentials": {
"hostname": "10.13.7.64",
"port": 3306,
"name": "cf_52",
"username": "w",
"password": "w",
"uri": "mysql://",
"jdbcUrl": "jdbc:mysql://10.193.78.64:"
},
"binding_options": {},
"gateway_data": null,
"gateway_name": "",
"syslog_drain_url": null,
"volume_mounts": [],
"name": null,
"last_operation": {
"type": "create",
"state": "succeeded",
"description": "",
"updated_at": "2019-03-19T20:07:25Z",
"created_at": "2019-03-19T20:07:25Z"
},
"app_url": "/v2/apps/73",
"service_instance_url": "/v2/service_instances/52",
"service_binding_parameters_url": "/v2/service_bindings/e0"
}
},
{
"metadata": {
"guid": "18",
"url": "/v2/service_bindings/18",
"created_at": "2019-03-19T20:07:27Z",
"updated_at": "2019-03-19T20:07:27Z"
},
"entity": {
"app_guid": "73",
"service_instance_guid": "ae",
"credentials": {
"credhub-ref": "/c/54"
},
"binding_options": {},
"gateway_data": null,
"gateway_name": "",
"syslog_drain_url": null,
"volume_mounts": [],
"name": null,
"last_operation": {
"type": "create",
"state": "succeeded",
"description": "",
"updated_at": "2019-03-19T20:07:27Z",
"created_at": "2019-03-19T20:07:27Z"
},
"app_url": "/v2/apps/73",
"service_instance_url": "/v2/service_instances/aec",
"service_binding_parameters_url": "/v2/service_bindings/18"
}
}
]
}
The current query only returns the credentials object:
jq '.resources[].entity.credentials | select(.["credhub-ref"])' test.json
Results in:
{
"credhub-ref": "/c/42"
}
{
"credhub-ref": "/c/54"
}
I need a query that outputs the parent objects app_guid and service_instance_guid too like the following:
}
"app_guid": "9c",
"service_instance_guid": "66",
"credentials": {
"credhub-ref": "/c/54"
},
{
"app_guid": "73",
"service_instance_guid": "ae",
"credentials": {
"credhub-ref": "/c/54"
}
A few good examples of how this can be done would go a long way for helping me better understand how JQ works.

Answer 1

This is one of many ways way to get the expected output:
jq '.resources[].entity | select(.credentials."credhub-ref") | {app_guid, service_instance_guid, credentials}' test.json
It will search for .credentials.credhub-ref in every entity object and will return app_guid, service_instance_guid, credentials as object if found.
Output:
{
"app_guid": "9c",
"service_instance_guid": "66",
"credentials": {
"credhub-ref": "/c/54"
}
}
{
"app_guid": "73",
"service_instance_guid": "ae",
"credentials": {
"credhub-ref": "/c/54"
}
}