[stable/kapacitor] Supply kapacitor.conf via ConfigMap/values.yaml

[jagregory]

Added support to generate a kapacitor.conf from values.yaml.

By default the config generated will mirror the default config Kapacitor uses. See generated with this chart vs the default kapacitor config.

The only difference between the YAML and the TOML is using a kapacitor key to contain the top-level config options, which need to be pulled out separately due to TOML being order-sensitive.

Without this, Kapacitor isn't very useful because you can't use the alerts without enabling a notification in the config.

[k8s-ci-robot]

Hi @jagregory. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with @k8s-bot 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.

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/test-infra repository. I understand the commands that are listed here.

[jackzampolin]

@jagregory You can enable the notifications through the API or through our dashboarding tool Chronograf. Relying on a config file breaks the latter functionality so I've implemented it in the ENV you see.

Another note on this approach, I've just submitted a PR to kubernetes/helm that adds a toToml template function that might make this code cleaner.

[viglesiasce]

@jackzampolin can we close this out?

[jackzampolin]

@viglesiasce Yup!