Introduce State Values(Environment Values + Defaulting)

[mumoshu]

This is a copy-paste of #361 (comment) for visibility.

---

We're going to introduce State Values, that should be the foundation for various useful features.

(Note that this isn't a breaking change)

---

We have a feature request that breaks .Environment.Values if done straightforward #398 (comment)

Alternatively, we can change the term to State Values, and:

• Make it accessible in the template with .Values(not .Environment.Values)

• Explicitly note in the documentation that Environment Values is for overriding (State) Values

• Deprecate .Environment.Values and recommend using .Values.

• .Values can be overrode with command-line args and environment values files(Question: How to handle global variables across helmfiles #398 (comment))

  # Internally this is an alias of `environments.default.values`
  values:
  - myAPIEndpoint: https://dev.example.com/
     mykey: myvalue
  
  environments:
    production:
      values:
      - myAPIEndpoint: https://prod.example.com/
  

  When --environment production

  • {{ .Environment.Values.mykey }} fails(This preserves the existing behavior)
  • {{ .Values.mykey }} results in myvalue cuz .Values is environments.default.values + environments.production.values

• It's .Values so the command-line args to set it from k-v pairs would naturally look like helmfile --set KEY=VALUE

• The command-line args to set it from a file it looks like helmfile --values FILE

• We recently implemented feat: specify env values from the parent to the nested state #622 but it should be changed. Use helmfiles[].values rather than helmfiles[].environment.values make it similar to its command-line flag variant --values.

  helmfiles:
  - name: sub.helmfile.yaml
    values:
      mykey: myvalue
  

• helmfile --environment NAME remains as-is. It set's the state's environment name.

• helmfile --set-envvar NAME=VALUE, helmfile --envvar-set, or helmfile --envvar sets envvars from NAME=VALUE pairs.

• helmfile --envvars-file FILE, or helmfile --envvars FILE sets environment variables from the FILE

For envvars, I personally prefer the combo of helmfile --envvars-file FILE and helmfile --envvar-set NAME=VALUE, as it seems user-friendly because (1)they naturally collocate in the flags list thati s alphabetically sorted (2) it's harder to confuse with --environment NAME.

[mumoshu]

helmfile --values FILE has been implemented as helmfile --state-values-file FILE and helmfile --set key=val as helmfile --state-values-file-set to avoid collision with the existing --values FILE flag of helmfile sync. See #644

[mumoshu]

values: is being added to the state file syntax and .Values is being added to the template syntax via #647

[mumoshu]

Please file another feature requests for adding helmfile ability to set envvars via command-line flags.