WIP Secret Source Implementation

[mstoykov]

What?

Adds an extensible secret sources. Basically #4139 but without http secret source as that turned out to have too many configuration problems. But it has a mock secret source which basically gets them form the cli arguments - probably should be renamed.

Usage:

import { secrets } from "k6";

export default () => {
	const my_secret = secrets.get("cool"); // get secret from a source with the provided identifier
	console.log(my_secret);
	secrets.get("else"); // get secret from a source with the provided identifier
	console.log(my_secret);
}

go run . run --secret-source=mock=cool=some:else=source script.js

or with a secret file:

cool=some
else=source

go run . run --secret-source=file=file.secret script.js

The extension points are under ./secretsource and mostly around the Get method which gets a secret and returns it.

The rest of k6 makes certain to not request it again and redact it from logs.

TODO:

• Should we throw an exception or return undefined on errors, or at least on not found secrets.
• Multiple secret sources is almost done bu not quite
• Unit Tests and likely some integration ones will be nice
• Have HTTP secret source? Maybe for later version
• Configuration currently only happens from CLI flags whihc might not be ideal and is definitely problematic as , is special so you need ot use some other character for separation like : in the mock configuraiton.
• Having Name be parsed by the internal parts before we actually make the secret source
• Having a way to define a Default secret source when named ones are also possible.
• Some Benchmarks will be nice
• Docs of any kind

Why?

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have run linter locally (make lint) and all checks pass.
• I have run tests locally (make tests) and all tests pass.
• I have commented on my code, particularly in hard-to-understand areas.

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