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
This adds `values` to state files as proposed in #640.
```yaml
values:
- key1: val1
- defaults.yaml
environments:
default:
- values:
- environments/default.yaml
production:
- values:
- environments/production.yaml
```
`{{ .Valuese.key1 }}` evaluates to `val1` if and only if it is not overrode via the production or the default env, or command-line args.
Resolves#640
* feat: helmfile as a go library
This removes almost all the dependencies from the helmfile core logic to urfave/cli. `main.go` is now a thin wrapper around the core logic implemented in `pkg/app`.
sgandon
KUOKA Yusuke