Modify value in the object containing a particular string using jq - json

Question

I am trying to modify a large json file (a Grafana dashboard), replacing a single value, then output the whole file with the change. How can I do this?
You can see the value I want to edit here. The actual file is quite large, so there are many other top-level values, but I only need to edit a specific item under the "templating" block.
"templating": {
"list": [
{
"allValue": ".*",
"current": {},
"datasource": "$Source",
"hide": 0,
"includeAll": false,
"label": null,
"multi": true,
"name": "node",
"options": [],
"query": "label_values(node_boot_time{env=~\"$env\"}, instance)",
"refresh": 1,
"regex": "",
"sort": 0,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
},
{
"allValue": null,
"current": {
"tags": [],
"text": "",
"value": ""
},
"datasource": "$Source",
"definition": "label_values(env)",
"hide": 0,
"includeAll": true,
"label": "env",
"multi": false,
"name": "env",
"options": [],
"query": "label_values(env)",
"refresh": 1,
"regex": "",
"skipUrlSync": false,
"sort": 1,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
},
{
"current": {
"tags": [],
"text": "",
"value": ""
},
"hide": 0,
"includeAll": false,
"label": null,
"multi": false,
"name": "Source",
"options": [],
"query": "prometheus",
"refresh": 1,
"regex": "",
"skipUrlSync": false,
"type": "datasource"
}
]
},
The piece I need to change is the block containing "query": "label_values(env)", and I just need to change the value of "regex": "",
I have tried:
jq '.templating.list[] | select(.name == "env") |= . + {regex:"*"}' "dashboard.json" > test.json
The problem is then it only prints the ".list[]" elements instead of the whole file. I need to be able to make this change for multiple other files that will have the same block, but not necessarily in the same place so I can't just select by index number.
Output of above script:
{
"allValue": ".*",
"current": {},
"datasource": "$Source",
"hide": 0,
"includeAll": false,
"label": null,
"multi": true,
"name": "node",
"options": [],
"query": "label_values(node_boot_time{env=~\"$env\"}, instance)",
"refresh": 1,
"regex": "",
"sort": 0,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
}
{
"allValue": null,
"current": {
"tags": [],
"text": "",
"value": ""
},
"datasource": "$Source",
"definition": "label_values(env)",
"hide": 0,
"includeAll": true,
"label": "env",
"multi": false,
"name": "env",
"options": [],
"query": "label_values(env)",
"refresh": 1,
"regex": "*",
"skipUrlSync": false,
"sort": 1,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
}
{
"current": {
"tags": [],
"text": "",
"value": ""
},
"hide": 0,
"includeAll": false,
"label": null,
"multi": false,
"name": "Source",
"options": [],
"query": "prometheus",
"refresh": 1,
"regex": "",
"skipUrlSync": false,
"type": "datasource"
}

Answer 1

Position |= earlier to retain the original structure.
.templating.list[] |= (select(.name == "env") .regex = "*")
Online demo

Answer 2

Your expected output isn't quite matching with your description of your problem. If your requirement is to find inside templating list find the query containing "label_values(env)" and update the regex to "" you need below. To change it to *, use regex = "*"
.templating.list[] |= ( select(.query == "label_values(env)").regex = "")
The key is to use the right path and use the select operator to get the object to update using the |= operator
jq-play snippet