Allow passing linodeApitoken and region as secretRef

[tchinmai7]

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Pull Request Guidelines:

Adding support for passing the LinodeAPIToken and region via secret references instead of raw helm values. This prevents the disclosure of the token in values files when using gitops practices.

1. Does your submission pass tests?
2. Have you added tests?
3. Are you addressing a single feature in this PR?
4. Are your commits atomic, addressing one change per commit?
5. Are you following the conventions of the language?
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7. Have you explained your rationale for why this feature is needed?
8. Have you linked your PR to an open issue

[komer3]

nit: New line here

[tchinmai7]

fixed

[komer3]

Question: Are we passing in the values when we install the helm chart? If yes, why is this part commented?

[tchinmai7]

Yes, these values can be passed in when installing. This is commented to keep backwards compatibility. Existing users of the chart can continue to pass in the token and region, new users can choose to use the secretRef. Didn't want to break usersa

[komer3]

LGTM!

[srust]

@schinmai-akamai can you add a unit test for this?

[tchinmai7]

Helm linting passes with the token and region set manually

$ helm lint deploy/chart --set apiToken="apiToken",region="us-east"      
==> Linting deploy/chart
[INFO] Chart.yaml: icon is recommended

1 chart(s) linted, 0 chart(s) failed

Helm linting passes with the token and region set via secret

$ helm lint deploy/chart --set secretRef.apiTokenRef="apiToken",secretRef.name="api",secretRef.regionRef="us-east"                 
==> Linting deploy/chart
[INFO] Chart.yaml: icon is recommended

1 chart(s) linted, 0 chart(s) failed

Helm template works with the secret being created when the apiToken and region is manually set

$  helm template foo deploy/chart --set apiToken="apiToken",region="us-east" --debug
---
# Source: ccm-linode/templates/ccm-linode.yaml
apiVersion: v1
kind: Secret
metadata:
  name: ccm-linode
  namespace: kube-system
stringData:
  apiToken: apiToken
  region: us-east
type: Opaque
---
# Source: ccm-linode/templates/daemonset.yaml
          env:
            - name: LINODE_API_TOKEN
              valueFrom:
                secretKeyRef:
                  name: "ccm-linode"
                  key: "apiToken"
            - name: LINODE_REGION
              valueFrom:
                secretKeyRef:
                  name: "ccm-linode"
                  key: "region"

Helm template works with secretReference - no secret, and correct values being passed.

$ helm template foo deploy/chart --set secretRef.apiTokenRef="apiToken",secretRef.name="api",secretRef.regionRef="us-east"
# Source: ccm-linode/templates/daemonset.yaml
          env:
            - name: LINODE_API_TOKEN
              valueFrom:
                secretKeyRef:
                  name: api
                  key: apiToken
            - name: LINODE_REGION
              valueFrom:
                secretKeyRef:
                  name: api
                  key: us-east