Directory called Kustomization incorrectly implies kustomization

[mflendrich]

Hi there! 👋

It seems that I have hit a corner case in Kustomization detection.

Summary

Current behavior: kustomization-controller fails if it encounters a directory called Kustomization in the repo.
Expected behavior:

1. reconciliation not failing
2. flux not refusing to descend into Kustomization/'s parent directory

I believe that this happens because the condition of this if should only fire for non-directories.

Reproduction

Suppose that I have source-controller and kustomization-controller running in my cluster and the following manifests applied:

apiVersion: source.toolkit.fluxcd.io/v1beta1
kind: GitRepository
metadata:
  name: cluster-contents
  namespace: something
spec:
  url: https://github.com/some-org/some-repo.git
  interval: 30s
  secretRef:
    name: some-https-basic-auth-secret

apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: cluster-contents
  namespace: something
spec:
  interval: 30s
  path: "./"
  prune: true
  sourceRef:
    kind: GitRepository
    name: cluster-contents

The repo contains only plain Kubernetes manifests (i.e. no Kustomizations, just plain k8s resources). That repo follows a naming convention for resource filenames: /<metadata.namespace>/<kind>/<metadata.name>.yaml

This works flawlessly until I add a resource of Kustomization kind (the use case is that I want to manage my flux2 Kustomizations from this repo). Per my naming convention, it lands in a file called along the lines of /michals-namespace/Kustomization/michals-kustomization.yaml. Once a directory called Kustomization gets pushed to the repository, reconciliation of the Kustomization resource cluster-contents begins to fail:

Status:
  Conditions:
    Last Transition Time:  2020-12-23T21:04:46Z
    Message:               kustomize build failed: accumulating resources: 2 errors occurred:
                           * accumulateFile error: "accumulating resources from './gitops': read /tmp/cluster-contents240645327/gitops: is a directory"
                           * accumulateDirector error: "couldn't make target for path '/tmp/cluster-contents240645327/gitops': unable to find one of 'kustomization.yaml', 'kustomization.yml' or 'Kustomization' in directory '/tmp/cluster-contents240645327/gitops'"


    Reason:                 BuildFailed
    Status:                 False
    Type:                   Ready
  Last Applied Revision:    (redacted)
  Last Attempted Revision:  (redacted)
  Observed Generation:      1
  Snapshot:
    Checksum:  (redacted)
    Entries:
      Kinds:
        /v1, Kind=Namespace:                                          Namespace
        apiextensions.k8s.io/v1, Kind=CustomResourceDefinition:       CustomResourceDefinition
        apiextensions.k8s.io/v1beta1, Kind=CustomResourceDefinition:  CustomResourceDefinition
        rbac.authorization.k8s.io/v1, Kind=ClusterRoleBinding:        ClusterRoleBinding
        rbac.authorization.k8s.io/v1beta1, Kind=ClusterRole:          ClusterRole
        rbac.authorization.k8s.io/v1beta1, Kind=ClusterRoleBinding:   ClusterRoleBinding
      Namespace:                                                      
      Kinds:
        /v1, Kind=Service:         Service
        /v1, Kind=ServiceAccount:  ServiceAccount
        apps/v1, Kind=Deployment:  Deployment
      Namespace:                   (redacted)
      Kinds:
        /v1, Kind=Service:                               Service
        apps/v1, Kind=Deployment:                        Deployment
        networking.k8s.io/v1, Kind=NetworkPolicy:        NetworkPolicy
        rbac.authorization.k8s.io/v1, Kind=Role:         Role
        rbac.authorization.k8s.io/v1, Kind=RoleBinding:  RoleBinding
      Namespace:                                         flux-system
      Kinds:
        apps/v1, Kind=Deployment:  Deployment
      Namespace:                   (redacted)
Events:
  Type    Reason  Age   From                  Message
  ----    ------  ----  ----                  -------
  Normal  error   49m   kustomize-controller  kustomize build failed: accumulating resources: 2 errors occurred:
          * accumulateFile error: "accumulating resources from './michals-namespace': read /tmp/cluster-contents051013649/michals-namespace: is a directory"
          * accumulateDirector error: "couldn't make target for path '/tmp/cluster-contents051013649/michals-namespace': unable to find one of 'kustomization.yaml', 'kustomization.yml' or 'Kustomization' in directory '/tmp/cluster-contents051013649/michals-namespace'"

Proposed fix

This line in kustomization_generator.go

					if fs.Exists(filepath.Join(path, kfilename)) {

should become something equivalent to

					if kpath := filepath.Join(path, kfilename); fs.Exists(kpath) && !fs.IsDir(kpath) {

If I get a green light from maintainers I'm happy to send a PR.

[stefanprodan]

Your fix looks ok to me, please open a PR. Thanks