When helmfile is run with `--environment NAME` and there was a base hemlfile that misses `environments`, helmfile had been trying to load env values for NAME and failing.
A base helmfile is allowed to reference values from within itself, but that's optional. In other words, a base helmfile that misses the env is okay as long as it doesn't self-reference env values.
So, this change allows missing env and env values while loading base helmfile. After loading, a base helmfile can fail due to referencing missing env values, but that's okay.
Fixes#1008
Closes#444 and #782
This is the final PR to fully cache and parallelize helm secret decryption. It threads the shared helmexec.Interface into the StateCreator and HelmState structs to be used during environment secret decryption. This should effectively cache secrets for the duration of a helmfile run, regardless of where they are first decrypted.
This change enhances helmfile to accept terraform-module-like URLs in nested state files a.k.a sub-helmfiles.
```yaml
helmfiles:
- # Terraform-module-like URL for importing a remote directory and use a file in it as a nested-state file
# The nested-state file is locally checked-out along with the remote directory containing it.
# Therefore all the local paths in the file are resolved relative to the file
path: git::https://github.com/cloudposse/helmfiles.git@releases/kiam.yaml?ref=0.40.0
```
The URL isn't equivalent to terraform module sources. The difference is that we use `@` to distinguish between (1) the path to the repository and directory containing the state file and (2) the path to the state file being loaded. This distinction provides us enough fleibiity to instruct helmfile to check-out necessary and sufficient directory to make the state file works.
Under the hood, it uses [hashicorp/go-getter](https://github.com/hashicorp/go-getter), that is used for [terraform module sources](https://www.terraform.io/docs/modules/sources.html) as well.
Only the git provider without authentication like git-credentials helper is tested. But theoretically any go-getter providers should work. Please feel free to test the provider of your choice and contribute documentation or instruction to use it :)
Resolves#347
KUOKA Yusuke
Kevin J. Qiu
chenrui
Eric Bailey
Kyrylo Lebediev
Travis Groth