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kubernetesjsonpath

Kubectl query for regex in JsonPath

I am trying to output the value for .metadata.name followed by the student's name in .spec.template.spec.containers[].students[] array using the regex in JsonPath for a Kubectl query.

I had actually asked a similar question linked here for this in jq.

How do I print a specific value of an array given a condition in jq if there is no key specified

The solution worked but I am wondering if there is an alternative solution for it using JsonPath or go-template perhaps (without the need for using jq).

For example, if I check the students[] array if it contains the word "Jeff", I would like the output to display as below:

student-deployment: Jefferson

What I've tried:

For JsonPath, I've tried the query below:

kubectl get deployment -o=jsonpath="{range .items[?(@.spec.template.spec.containers[*].students[*])]}{'\n'}{.metadata.name}{':\t'}{range .spec.template.spec.containers[*]}{.students[?(@=="Jefferson")]}{end}{end}"

But this only works to evaluate for matching words. Would it be possible to use JsonPath to query for regex as I've read here that JsonPath regex =~ doesn't work? I did try to use | grep and findstr but it still returned all values inside the array back to me. Other than jq, is there another way to retrieve the regex output?

https://github.com/kubernetes/kubernetes/issues/61406

The deployment template below is in json and I shortened it to only the relevant parts.

{
    "apiVersion": "v1",
    "items": [
        {
            "apiVersion": "apps/v1",
            "kind": "Deployment",
            "metadata": {
                "name": "student-deployment",
                "namespace": "default"
            },
            "spec": {
                "template": {
                    "spec": {
                        "containers": [
                            {
                                "students": [
                                        "Alice",
                                        "Bob",
                                        "Peter",
                                        "Sally",
                                        "Jefferson"
                                ]
                            }
                        ]
                    }
                }
            }
        }
    ]
}
Solution

  • The documentation for JSONPath Support clearly describes that it is not possible with JSONPath and you can use jq.

    https://kubernetes.io/docs/reference/kubectl/jsonpath/

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