feat: additional template functions

[matkam]

Description

Adds a few useful text/template functions:

• replaceAll: strings.replaceAll
• isIPv6: exposes an existing function that returns a bool to let you know if a string is an IPv6 address
• isIPv4: a new function that returns a bool to let you know if a string is an IPv4 address

N/A

Checklist

• [x] Unit tests updated
• [x] End user documentation updated

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: matkam / name: Mathew Kamkar (6b0d792a19bc0934a83cd9367a344e7c9aabdc64, a5f3a17603fa4caba6da44c5ed9144181f533556, 68be9bda50747f39ea4052bd5ec264b5de5164b7, b0f3beb89992bf0d7bc127ad87dad912453eb92d, b610c94a5c0925ef49c37370e0faa819a7f4850e, 42f79f82501bd40a424db1550fd1aa7a491cbbdd, 88bfa6083f86225d6991adeacff1f5bf6ad9bc8f, 267cb1f1b612be2a641d915ab675c0f1e588ce78)

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @matkam. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[johngmyers]

Please submit a CLA per the instructions above.

[matkam]

Please submit a CLA per the instructions above.

Yes 👍 I'm just waiting on my employer to click the button.

[matkam]

@johngmyers we are good to go here 👍

[johngmyers]

Sprig has replace, which is similar. Perhaps we should follow their syntax?

[johngmyers]

/ok-to-test

[matkam]

Sprig has replace, which is similar. Perhaps we should follow their syntax?

does replace work differently? I could also add strings.replace to the FuncMap.

[johngmyers]

I believe replace has the arguments in a different order. See the documentation in https://masterminds.github.io/sprig/strings.html

[matkam]

I believe replace has the arguments in a different order. See the documentation in https://masterminds.github.io/sprig/strings.html

sprig looks like a nice package. how about just importing it and using hermeticTxtFuncMap like this:

func parseTemplate(fqdnTemplate string) (tmpl *template.Template, err error) {
	if fqdnTemplate == "" {
		return nil, nil
	}
	
	funcs := sprig.HermeticTxtFuncMap()
	funcs["isIPv6"] = isIPv6String
	funcs["isIPv4"] = isIPv4String

	return template.New("endpoint").Funcs(funcs).Parse(fqdnTemplate)
}

[matkam]

@johngmyers let me know what you think. I've updated the template functions to include Sprig's hermetic text functions, and fixed the isIPv4String function so that it only returns true for valid IPv4 strings.

[mloiseleur]

@matkam Wdyt about adding isIPv4 and isIPv6 directly into slim-sprig ?

[matkam]

@mloiseleur https://github.com/go-task/slim-sprig/pull/16

[mloiseleur]

/hold for https://github.com/go-task/slim-sprig/pull/16

[k8s-ci-robot]

@matkam: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-external-dns-lint	c16c17556b32a6fe4d85960df82eeca6257af939	link	true	/test pull-external-dns-lint

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[mloiseleur]

@matkam Since slim-sprig maintainer does not review your PR, I think we can merge this one. Do you think you can rebase this PR ? And precise in documentation those additional functions of isIPv4 and isIPv6 ?

[matkam]

@mloiseleur done!

[mloiseleur]

/lgtm

[matkam]

@mloiseleur whats the next step required to get this merged?

[mloiseleur]

A review from @szuecs or @Raffo They will review this PR when they have time.

[mloiseleur]

/unhold

[mloiseleur]

/retitle feat: additional template functions

[simonostendorf]

Hello, I would like to see this merged and released. What needs to be done?

[k8s-ci-robot]

New changes are detected. LGTM label has been removed.

[k8s-ci-robot]

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