Allow optional definition of ingress

[drewburr]

Removes the requirement of setting ingress.enabled: false for extraPorts. For example, an item in extraPorts[] needing no ingress currently requires:

extraPorts:
  - name: map
    protocol: TCP
    ingress:
      enabled: false
    ...

If ingress is omitted, the following error is thrown:

Error: template: minecraft-toiletbowl/charts/minecraft/templates/extraports-ing.yaml:3:26: executing "minecraft-toiletbowl/charts/minecraft/templates/extraports-ing.yaml" at <.ingress.enabled>: nil pointer evaluating interface {}.enabled

With this update, we can safely omit the ingress object entirely:

extraPorts:
  - name: map
    protocol: TCP
    ...

[itzg]

Thanks! Can you also bump the chart's minor version? (PR/merge process currently requires it 😞)

[itzg]

Very interesting. So this allows for nil-safe access to objects? So you happen to know where in the helm docs they describe that?

[drewburr]

I actually found this while poking through Google, with this StackOverflow post leading me to the right answer.

In Helm we can wrap a value that we might consider optional in brackets.

type: {{ (.Values.fpm.service).type | default "NodePort" }}

Now when we try to run a helm template / install, it will consider .Values.fpm.service to be optional. We would still run into a Nil pointer if .Values.fpm is not set. So you must ensure to encapsulate up until where should be considered optional, as you can see in the example I provided, I did not place brackets around .type otherwise, it would try to find service which may not exist.

Digging into this further, another StackOverflow post notes that this behavior comes from Go's text/template library. It seems that something like {{ if default "" .ingress.enabled }} is called a "pipeline" and adding the parenthesis makes a pipeline within the pipeline, like nested operators if default "" (.ingress).enabled. The nested pipeline returns a nil value under a suite of negative circumstances, which is then used instead of a nil pointer when accessing .enabled (docs).

If the value of the pipeline is empty, no output is generated
...
The empty values are false, 0, any nil pointer or interface value, and any array, slice, map, or string of length zero.

Very interesting!

[drewburr]

Thanks! Can you also bump the chart's minor version? (PR/merge process currently requires it 😞)

Good catch! Thanks for the heads up, I'll keep this in mind in the future