Add Bash Variable as key for JSON object

Question

I am running a command that is pulling json from kubectl and I need to take that json and input it into another json array.

Currently, my command looks like this

kubectl get ingress -o json | jq --arg context "$i" '{"$context":[{namespace: .items[].metadata.namespace, host: .items[].spec.rules[].host}]}'

but my json response is the following -

{
  "$context": [
    {
      "namespace": "test",
      "host": "test.test.com"
    }
  ]
}

I essentially want my json output to resolve the $context variable to include the value from bash variable $i, not the string "$context". Thank you for any help!

Answer 1

When constructing an object in jq, the key, if it's not "identifier-like", must be enclosed in parentheses:

$ cat file
{"items":[{"metadata":{"namespace":"test"}, "spec":{"rules":[{"host":"test.test.com"}]}}]}

$ jq --arg context "foo" '{($context): [{namespace: .items[].metadata.namespace, host: .items[].spec.rules[].host}]}' file
# .........................^........^

{
  "foo": [
    {
      "namespace": "test",
      "host": "test.test.com"
    }
  ]
}

"identifier-like" == "composed of alphanumeric characters and underscore, and not started with a digit"