Add content loader docs (#305)

Co-authored-by: Johannes Schnatterer <johannes.schnatterer@cloudogu.com>
Co-authored-by: Thomas Michael <thomas.michael@cloudogu.com>

Author: 3 people

README.md

@@ -10,6 +10,8 @@ Kubernetes clusters:
 * Pipelines: Example applications using [Jenkins](#jenkins) with the [gitops-build-lib](https://github.com/cloudogu/gitops-build-lib) and [SCM-Manager](#scm-manager)
 * Ingress Controller: [ingress-nginx](https://github.com/kubernetes/ingress-nginx/)
 * Certificate Management: [cert-manager](#certificate-management)
+* [Content Loader](docs/content-loader/content-loader.md): Completely customize what is pushed to Git during installation.
+  This allows for adding your own end-user or IDP apps, creating repos, adding Argo CD tenants, etc.
 * Runs on: 
   * local cluster (try it [with only one command](#tldr)), 
   * in the public cloud, 

docs/content-loader/argocd/argocd/applications/example-tenant.ftl.yaml

@@ -0,0 +1,23 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: example-tenant
+  namespace: ${config.application.namePrefix}argocd
+# finalizer disabled, because otherwise everything under this Application would be deleted as well, if this Application is deleted by accident
+#  finalizers:
+#    - resources-finalizer.argocd.argoproj.io
+spec:
+  destination:
+    namespace: ${config.application.namePrefix}argocd
+    server: https://kubernetes.default.svc
+  project: argocd
+  source:
+    path: argocd/
+    repoURL:  "http://scmm.${config.application.namePrefix}scm-manager.svc.cluster.local/scm/repo/${config.application.namePrefix}example-tenant/gitops"
+    targetRevision: main
+    directory:
+      recurse: true
+  syncPolicy:
+    automated:
+      prune: false # is set to false to prevent projects to be deleted by accident
+      selfHeal: true

docs/content-loader/argocd/argocd/projects/example-tenant.ftl.yaml

@@ -0,0 +1,33 @@
+apiVersion: argoproj.io/v1alpha1
+kind: AppProject
+metadata:
+  name: example-tenant
+  namespace: ${config.application.namePrefix}argocd
+  annotations:
+<#if config.features.mail.active>
+     notifications.argoproj.io/subscribe.email: ${config.features.argocd.emailToUser}
+</#if>
+spec:
+  description: Contains examples of end-user applications
+  destinations:
+  - namespace: ${config.application.namePrefix}example-tenant-production
+    server: https://kubernetes.default.svc
+  - namespace: ${config.application.namePrefix}example-tenant-staging
+    server: https://kubernetes.default.svc
+  sourceRepos:
+  - http://scmm.${config.application.namePrefix}scm-manager.svc.cluster.local/scm/repo/${config.application.namePrefix}example-tenant/gitops
+  - http://scmm.${config.application.namePrefix}scm-manager.svc.cluster.local/scm/repo/${config.application.namePrefix}example-tenant/nginx-helm-umbrella
+  - https://raw.githubusercontent.com/bitnami/charts/archive-full-index/bitnami
+
+  # allow to only see application resources from the specified namespace
+  sourceNamespaces:
+    - '${config.application.namePrefix}example-tenant-staging'
+    - '${config.application.namePrefix}example-tenant-production'
+
+  # Allow all namespaced-scoped resources to be created
+  namespaceResourceWhitelist:
+    - group: '*'
+      kind: '*'
+
+  # Deny all cluster-scoped resources from being created. Least privilege.
+  clusterResourceWhitelist:

docs/content-loader/content-hooks-folder-based.png

@@ -0,0 +1,55 @@
+# $schema: https://raw.githubusercontent.com/cloudogu/gitops-playground/main/docs/configuration.schema.json
+content:
+  repos:
+    - url: https://github.com/cloudogu/gitops-build-lib
+      target: 3rd-party-dependencies/gitops-build-lib
+      overwriteMode: RESET
+    - url: https://github.com/cloudogu/ces-build-lib
+      target: 3rd-party-dependencies/ces-build-lib
+      overwriteMode: RESET
+    - url: https://github.com/cloudogu/spring-boot-helm-chart
+      target: 3rd-party-dependencies/spring-boot-helm-chart
+      overwriteMode: RESET
+    - url: https://github.com/cloudogu/spring-petclinic
+      target: example-tenant/petclinic-plain
+      ref: feature/gitops_ready
+      targetRef: main
+      #      ref: b0738b2
+      overwriteMode: UPGRADE
+      createJenkinsJob: true
+    - url: https://github.com/cloudogu/spring-petclinic
+      target: example-tenant/petclinic-helm
+      ref: feature/gitops_ready
+      targetRef: main
+      overwriteMode: UPGRADE
+      createJenkinsJob: true
+    - url: 'https://github.com/cloudogu/gitops-playground.git'
+      path: 'docs/content-loader'
+      ref: main
+      templating: true
+      type: FOLDER_BASED
+      overwriteMode: UPGRADE
+
+  namespaces:
+#    - ${config.application.namePrefix}example-tenant-production
+#    - ${config.application.namePrefix}example-tenant-staging
+    - example-tenant-production
+    - example-tenant-staging
+  variables:
+    umbrella:
+      nginxAnnotation: 'my value'
+    some: other
+
+application:
+  yes: true
+  baseUrl: http://localhost
+#  namePrefix: customer-1
+jenkins:
+  active: true
+registry:
+  active: true
+features:
+  argocd:
+    active: true
+  ingressNginx:
+    active: true