feat: allow using external variables in export and env list

[sabeechen]

Using std.extVar in an inline environment's definition will cause tk env list and tk export ... --recursive to fail.

An example use case (what I'm writing this to support), is when you have inline environments whose namespace needs to be set at runtime, such as a review environment whos namespace is dynamic eg:

{
    prod: {
        apiVersion: 'tanka.dev/v1alpha1',
        kind: 'Environment',
        metadata: {
            name: 'prod',
        },
        spec: {
            namespace: 'prod',
            applyStrategy: 'server',
        },
    },
    review: {
        apiVersion: 'tanka.dev/v1alpha1',
        kind: 'Environment',
        metadata: {
            name: 'review',
        },
        spec: {
            namespace: std.extVar('reviewNamespace'),
            applyStrategy: 'server',
        },
    }
}

Tanka has a bunch of different ways one could work around this, but its very convenient to be able to specify the default namespace so succinctly.

• For tk export ... --recursive the JsonnetOpts were already parsed and just needed to be plumbed through to where environments are discovered.
• For tk env list, the ext-str and tla-str arguments needed to be added to the command.

[CLAassistant]

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[zerok]

Thank you 🙂 Makes sense and look good! Can you please just fix that one linting issues?

[sabeechen]

Thanks for the review!

[zerok]

Thank you for working on this 🙂

[sabeechen]

Awesome! I've made a fork of tanka that my org is currently using as a workaround so its not like we're hurting, but is there a way to know when when this will be included in a standard release?

[zerok]

I wanted to cut a new release some time this week if time permits 🙂

[zerok]

v0.28.0 is out now 😄 https://github.com/grafana/tanka/releases/tag/v0.28.0