app-of-apps.yaml

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: apps
  namespace: kube-system
spec:
  project: default
  source:
    repoURL: https://github.com/mumoshu/configrepo.git
    targetRevision: HEAD
    path: argocd
  destination:
    server: https://kubernetes.default.svc
    namespace: kube-system

apps.yaml.tpl

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: guestbook
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/mumoshu/configrepo.git
    targetRevision: {{.commit}}
    path: apps/guestbook
  destination:
    server: https://kubernetes.default.svc
    namespace: guestbook
---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: api
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/mumoshu/configrepo.git
    targetRevision: {{.commit}}
    path: apps/api
  destination:
    server: https://kubernetes.default.svc
    namespace: api

variant-mod-argocd-proposal.md

module "myapp" {
  dependency "exec" "helmfile" {
    command = "go"
    args = ["run", "main.go"]
    version = "> 0.94.0"
  }
  
  dependency "timestamp_git" "configrepo" {
    # dep.configrepo.version looks like "20200225.1230.40-<commit id>"
    # and it is updated only when the directory `./apps` is updated after "2020.2.25 12:30:40 UTC"
    source = "github.com/mumoshu/configrepo/master/apps"
  }
  
  dependency "dockerimage" "guestbook" {
    source = "mumoshu/guestbook"
  }
  
  dependency "dockerimage" "api" {
    source = "mumoshu/api"
  }

  file "argocd/apps.yaml" {
    source = "apps.yaml.tpl"
    args = {
      commit = split(dep.configrepo.version, "-")[1]
    }
  }
  
  directory "helmfiles/guestbook" {
    source = "./helmfile-base"
    
    # some additional files and helmfile snippets...
  }

  directory "apps/guestbook" {
    source = "./helmfiles/guestbook"
    
    exec {
      command = "bash"
      args = list("-c", "helmfile -f ${source} template --state-values-set image.tag=${dep.guestbook.version} > ${dir}/all.yaml")
    }
  }
  
  directory "helmfiles/api" {
    source = "./helmfile-base"
    
    # some additional files and helmfile snippets...
  }

  directory "apps/api" {
    source = "./helmfiles/api"
    
    exec {
      command = "bash"
      args = list("-c", "helmfile -f ${source} template --state-values-set image.tag=${dep.api.version} > ${dir}/all.yaml")
    }
  }
}