I was looking for a solution but I couldn't find any.

I have a bash script which executes something like this:

kubectl get services -o=json | \
jq '.items[].metadata.annotations | '\
   'select (."my-ingress/enabled" == "true") | '\
   '{"my-ingress/path", "my-ingress/service-name", "my-ingress/service-port"}'

Which means it can take list of the services, filter and take only with annotations my-ingress/enabled == true

Based on that result it creates dynamically YAML for Ingress and loads it.

Everywhere I was looking, Helm is using templates and other fancy approaches but nowhere I could find any information how to ask K8S about some resources and based on that info build YAML.

Is this possible at all?

Note: calling Bash to prepare some kind values.yaml is not an option in my case.

CodePudding user response：

You may use HELM's lookup function to query the cluster

The lookup function can be used to look up resources in a running cluster. The synopsis of the lookup function is lookup apiVersion, kind, namespace, name -> resource or resource list.

parameter type apiVersion string kind string namespace string name string Both name and namespace are optional and can be passed as an empty string ("").

{{ range $index, $service := (lookup "v1" "Service" "mynamespace" "").items }}
    {{/* do something with each service */}}
{{ end }}

Important note:

Keep in mind that Helm is not supposed to contact the Kubernetes API Server during a helm template or a helm install|update|delete|rollback --dry-run, so the lookup function will return an empty list (i.e. dict) in such a case.