feat: add support for multiple helmfile "environments" to be targeted on the CLI

[bitsofinfo]

Currently I can only do this

helmfile -f myhelmfile.yaml -e myenv1 apply

Would be great to be able to do this, where when multiple are present, they are merged into a single .Environment

helmfile -f myhelmfile.yaml -e app1,cluster1 apply

OR

helmfile -f myhelmfile.yaml -e app1 -e cluster1 apply

Why?

Consider this:

myhelmfile.yaml

bases:
  - environments.yaml
---
releases:
  - name: myapp
    namespace: default
    chart: stable/nginx-ingress
    values:
      -  someArgument: {{.Environment.cluster.name}}
          anotherArgument {{.Environment.app.setting1}}

environments.yaml

environments:
  app1:
    values:
      - app1.yaml
  app2:
    values:
      - app2.yaml
  ...
  app1000:
    values:
      - app1000.yaml
  cluster1:
     values:
       - cluster1.yaml
  cluster2:
     values:
       - cluster2.yaml

I have a handful of clusters, but hundreds of apps. Each release of an app definitely has "helmfile-environment" vars specific to an "app" but some of them while consumed by an app's chart, are more logically grouped and specific to a cluster. Being able to do it this way would let me be a bit more DRY.

CURRENT WORKAROUND

NOTE: currently I can achieve this as similar to the below, it works but not ideal as I have to set an ENV var then use that as a dynamic key to fetch it from a "clusters" dict (i.e. via sprig values)

export CLUSTER_NAME=cluster1; helmfile -f myhelmfile.yaml -e app1 apply

myhelmfile.yaml

bases:
  - environments.yaml
---

{{- $clusterEntry := pick .Environment.Values.clusters (env CLUSTER_NAME) }}
{{- $cluster := values $clusterEntry | first }}

releases:
  - name: myapp
    namespace: default
    chart: stable/nginx-ingress
    values:
      -  someArgument: {{$cluster.name}}
          anotherArgument {{.Environment.app.setting1}}

environments.yaml

environments:
  app1:
    values:
      - app1.yaml
      - allclusters.yaml
  app2:
    values:
      - app2.yaml
      - allclusters.yaml
  ...
  app1000:
    values:
      - app1000.yaml
      - allclusters.yaml
 

allclusters.yaml

clusters:
  cluster1:
     name: xxxxxx
     ...
   cluster2:
     ....

potentially related to #361

[mumoshu]

@bitsofinfo Thanks!

My understanding is that this use-case can be addressed with the latest proposal made in #361, with:

values:
- allclusters.yaml

environments:
  app1:
    values:
      - app1.yaml
  app2:
    values:
      - app2.yaml
  ...
  app1000:
    values:
      - app1000.yaml

For app1, .Values is allclusters.yaml + app1.yaml, wheres the latter merges into the former.

Am I correct?

[bitsofinfo]

perfect, then that will provide basically the same thing! cool