"no such file error" on specifying helm values file with protocol

[rgeraskin]

Describe the bug

I`m trying to use the helm downloader plugin with helm secrets as described here. Doing so I try to avoid implementing a wrapper to helm binary to use helm secrets.

To Reproduce

1. Build argocd image with helm secrets plugin

2. Add app with source.helm.valueFiles in "downloader format":

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: apps
  namespace: argocd
spec:
  destination:
    name: in-cluster
    namespace: argocd
  project: default
  source:
    helm:
      valueFiles:
      - secrets://secrets.yaml
    path: apps
    repoURL: https://xxx

Expected behavior

It should work like helm template -f secrets://secrets.yaml .

Version

argocd: v2.0.4+0842d44
  BuildDate: 2021-06-23T01:27:53Z
  GitCommit: 0842d448107eb1397b251e63ec4d4bc1b4efdd6e
  GitTreeState: clean
  GoVersion: go1.16
  Compiler: gc
  Platform: linux/amd64
FATA[0000] Argo CD server address unspecified

Logs

Error: open secrets://secrets.yaml: no such file or directory

Unable to save changes: application spec is invalid: InvalidSpecError: Unable to generate manifests in apps: rpc error: code = Unknown desc = `helm template . --name-template apps --namespace argocd --values secrets://secrets.yaml --api-versions v1 --api-versions apiregistration.k8s.io/v1 --api-versions apiregistration.k8s.io/v1beta1 --api-versions extensions/v1beta1 --api-versions apps/v1 --api-versions events.k8s.io/v1beta1 --api-versions authentication.k8s.io/v1 --api-versions authentication.k8s.io/v1beta1 --api-versions authorization.k8s.io/v1 --api-versions authorization.k8s.io/v1beta1 --api-versions autoscaling/v1 --api-versions autoscaling/v2beta1 --api-versions autoscaling/v2beta2 --api-versions batch/v1 --api-versions batch/v1beta1 --api-versions certificates.k8s.io/v1beta1 --api-versions networking.k8s.io/v1 --api-versions networking.k8s.io/v1beta1 --api-versions policy/v1beta1 --api-versions rbac.authorization.k8s.io/v1 --api-versions rbac.authorization.k8s.io/v1beta1 --api-versions storage.k8s.io/v1 --api-versions storage.k8s.io/v1beta1 --api-versions admissionregistration.k8s.io/v1 --api-versions admissionregistration.k8s.io/v1beta1 --api-versions apiextensions.k8s.io/v1 --api-versions apiextensions.k8s.io/v1beta1 --api-versions scheduling.k8s.io/v1 --api-versions scheduling.k8s.io/v1beta1 --api-versions coordination.k8s.io/v1 --api-versions coordination.k8s.io/v1beta1 --api-versions node.k8s.io/v1beta1 --api-versions discovery.k8s.io/v1beta1 --api-versions argoproj.io/v1alpha1 --api-versions crd.k8s.amazonaws.com/v1alpha1 --api-versions vpcresources.k8s.aws/v1beta1 --include-crds` failed exit status 1: Error: open secrets://secrets.yaml: no such file or directory

[rgeraskin]

My mistake. I should not only add the helm secrets plugin but also set the HELM_PLUGINS variable as mentioned in the docs and #1153.

So now I can use a plugin without a wrapper.