While writing docs in the previous commit, I noticed that we'd been
inconsistent in the naming scheme. Wikipedia's back-compat article
redirects from "backwards" to "backward", so I figure that's a
reasonable source of authority for which form to use.
The goal with these changes was to give users a clearer, more readable
interface, so we should present that interface up front and only
document the aliases as a backward-compatibility option.
I've renamed the envconfig tags to reflect the switch, but I left the
actual field names the same. I think they're sufficiently meaningful
inside the code, and leaving them unchanged avoids making a bunch of
churn in the rest of the code.
We'd like to support it eventually, but the current state of affairs
doesn't justify the effort.
Also removed some vestigial code that was copy-pasta from the kubeconfig
in drone-helm.
I was unhappy with the comments-in-yaml approach; it required
duplicating a lot of information and it was hard to find a balance
between "usefully thorough" and "readably concise.""
This change revealed more about how the system needs to work, so there
are some supporting changes:
* helm.upgrade and helm.help are now vars rather than raw functions.
This allows unit tests to target the "which step should we run"
logic directly by comparing function pointers, rather than having to
configure/prepare a fully-valid Plan and then infer the logic’s
correctness based on the Plan’s state.
* configuration that's specific to kubeconfig initialization is now part
of the InitKube struct rather than run.Config, since other steps
shouldn’t need access to those settings (particularly the secrets).
* Step.Execute now receives a run.Config so it can log debug output.
I'm vacillating about the choice to have separate Config structs in the
`helm` and `run` packages. I can't tell whether it's "good separation of
concerns" or "cumbersome and over-engineered." It seems appropriate at
the moment, though.
