用jq从json中的一行中提取值 Linux bash

Question

I am extending here my recent question about jq since my requirements changed and I am still confused with map function.

Given such a service-def-test.json (very simplified from my real use case):

{
    "definition": {
        "services": [{
                "image": {
                    "name": "img1",
                    "tag": "2.0.1"
                }
            }, {
                "image": {
                    "name": "img2",
                    "tag": "1.4.0"
                }
            }, {
                "image": {
                    "name": "img3",
                    "tag": "1.2.5"
                }
            }
        ]
    }
}

I now would like to get a one-line list of values:

[img1:2.0.1, img2:1.4.0, img3:1.2.
to store eventually in a COMPONENT_IMAGES variable.

From the previous answer,

jq -r '.definition.services | " "COMPONENT_IMAGES=\"\(map(.image.name, .image.tag) | join(", "))\"" ' service-def-test.json

generates

COMPONENT_IMAGES="img1, 2.0.1, img2, 1.4.0, img3, 1.2.5"

but this I want only 3 items in my output array.

I am looking to get

COMPONENT_IMAGES="img1:2.0.1, img2:1.4.0, img3:1.2.5"

What am I missing here? Thanks!

Answer 1

map lets you filter each array item individually. Here, we descend to .image , and concatenate the value of .name , a literal colon ":" , and the value of .tag . The mapped array can then be join ed with a glue string ", " .

jq -r '
  .definition.services
  | "COMPONENT_IMAGES=\"" + (map(.image | .name + ":" + .tag) | join(", ")) + "\""
'

COMPONENT_IMAGES="img1:2.0.1, img2:1.4.0, img3:1.2.5"

Demo

---

If you prefer using string interpolation , here's its equivalent:

jq -r '
  .definition.services
  | "COMPONENT_IMAGES=\"\(map(.image | "\(.name):\(.tag)") | join(", "))\""
' 

COMPONENT_IMAGES="img1:2.0.1, img2:1.4.0, img3:1.2.5"

Demo