Can we create a setter contains list of object using kpt? - kubernetes

Question

I've noticed that we can crate a setter contains list of string based on kpt [documentation][1]. Then I found out that complex setter contains list of object is not supported based on [this github issue][1]. Since the issue itself mentioned that this should be supported in kpt function can we use it with the current kpt function version?
[1]: Kpt Apply Setters. https://catalog.kpt.dev/apply-setters/v0.1/
[1]: Setters for list of objects. https://github.com/GoogleContainerTools/kpt/issues/1533

Answer 1

I've discussed a bit with my coworkers, and turned out this is possible by doing the following setup:
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 4 # kpt-set: ${nginx-replicas}
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: "nginx:1.16.1" # kpt-set: nginx:${tag}
ports:
- protocol: TCP
containerPort: 80
---
apiVersion: v1
kind: MyKind
metadata:
name: foo
environments: # kpt-set: ${env}
- dev
- stage
---
apiVersion: v1
kind: MyKind
metadata:
name: bar
environments: # kpt-set: ${nested-env}
- key: some-key
value: some-value
After that we can define the following setters:
apiVersion: v1
kind: ConfigMap
metadata:
name: setters
data:
env: |-
- prod
- dev
nested-env: |-
- key: some-other-key
value: some-other-value
nginx-replicas: "3"
tag: 1.16.2
And then we can call the following command:
$ kpt fn render apply-setters-simple
I've send a Pull Request to the repository to add documentation about this.