error when running kpt fns against a package containing kustomization.yaml

[ryane]

Expected behavior

Running functions like set-labels, set-annotations, and set-namespace should work correctly in a package that contains a kustomization.yaml.

Actual behavior

The functions fail with an error like:

$ kpt fn render . 
Package "kpt-test":
[RUNNING] "gcr.io/kpt-fn/set-labels:v0.1"
[FAIL] "gcr.io/kpt-fn/set-labels:v0.1"
  Results:
    [ERROR] failed to run function: missing metadata.name in object {map[apiVersion:kustomize.config.k8s.io/v1beta1 kind:Kustomization metadata:map[annotations:map[config.k8s.io/id:2 config.kubernetes.io/index:0 config.kubernetes.io/path:kustomization.yaml]] resources:[deploy.yaml]]}
  Stderr:
    "[error] /// : failed to run function: missing metadata.name in object {map[apiVersion:kustomize.config.k8s.io/v1beta1 kind:Kustomization metadata:map[annotations:map[config.k8s.io/id:2 config.kubernetes.io/index:0 config.kubernetes.io/path:kustomization.yaml]] resources:[deploy.yaml]]}"
  Exit code: 1

Information

$ kpt version
1.0.0-alpha.5
$ kustomize version
{Version:kustomize/v4.1.3 GitCommit:0f614e92f72f1b938a9171b964d90b197ca8fb68 BuildDate:2021-05-20T20:52:40Z GoOs:linux GoArch:amd64}

Steps to reproduce the behavior

In an empty directory:

$ kubectl create deploy nginx --image nginx --dry-run=client -oyaml > deploy.yaml
$ kustomize create
$ kustomize edit add resource deploy.yaml
$ kustomize build | kpt pkg tree
kpt-test-2
├── [deploy.yaml]  Deployment nginx
└── [kustomization.yaml]  Kustomization
$ kpt pkg init .
writing Kptfile
writing README.md
$ kpt fn render .
Package "kpt-test-2":
Successfully executed 0 function(s) in 1 package(s).
$ kpt fn eval . --image gcr.io/kpt-fn/set-namespace:v0.1 -- namespace=nginx                                                                                      [9:51:35]
[RUNNING] "gcr.io/kpt-fn/set-namespace:v0.1"
[FAIL] "gcr.io/kpt-fn/set-namespace:v0.1"
  Results:
    [ERROR] failed to run function: missing metadata.name in object {map[apiVersion:kustomize.config.k8s.io/v1beta1 kind:Kustomization metadata:map[annotations:map[config.k8s.io/id:2 config.kubernetes.io/index:0 config.kubernetes.io/path:kustomization.yaml]] resources:[deploy.yaml]]}
  Stderr:
    "[error] /// : failed to run function: missing metadata.name in object {map[apiVersion:kustomize.config.k8s.io/v1beta1 kind:Kustomization metadata:map[annotations:map[config.k8s.io/id:2 config.kubernetes.io/index:0 config.kubernetes.io/path:kustomization.yaml]] resources:[deploy.yaml]]}"
  Exit code: 1
$ mv kustomization.yaml kustomization.yaml.bak

$ kpt fn eval . --image gcr.io/kpt-fn/set-namespace:v0.1 -- namespace=nginx                                                                                      [9:54:28]
[RUNNING] "gcr.io/kpt-fn/set-namespace:v0.1"
[PASS] "gcr.io/kpt-fn/set-namespace:v0.1"

Same errors if I invoke functions declaratively or use the unstable tag. So far, I get the errors with set-labels, set-annotations, and set-namespace. apply-setters does not seem to be affected. I haven't tried others.

[droot]

@ryane these functions require resources to be a valid KRM resource (must have a valid apiVersion, kind and metadata.name fields). So adding metadata.name will resolve that.

Can you share more what is the scenario here ? how are you planning to use kustomize here ?

[natasha41575]

@ryane If you are able, we are still interested in knowing more about your use case. We have a few ideas for solutions, but in order to properly resolve this issue we'd like to know more about how you are planning to use kustomize here.

[ryane]

So adding metadata.name will resolve that

This was actually the first thing I tried but it broke the (admittedly old) version of kustomize we are on (unknown field "metadata"). However, this prompted me to double check and I see that more recent versions of kustomize now allow you to set metadata. Thanks!

Although we are not currently using live, our use of kpt + kustomize has a lot of similarities to what is described in #1545. We have built (pre-1.0-alpha) kpt packages that have setters to configure patches, transformers, components, etc. for pre-existing kustomize bases (that we may or may not control).

[natasha41575]

@ryane Thanks for getting back to us! I'm glad setting metadata worked for you. I'm going to close this issue as resolved, but feel free to reopen if you have more to discuss.