Support for postRenderer in HelmRelease

[jkotiuk]

Hey,

Would it be possible to add support for HelmRelease PostRenderer?

The helm output would have to be piped through Kustomize to add those patches from postRenders section. Implementation could be based on a solution like this https://alysivji.github.io/helm-post-rendering-hook.html.

[allenporter]

Seems possible! So if I understand right, this would make a synthetic kustomization to pipe into kustomize? Is the logic for image documented? it seems like it needs to know all the various resource types, if i understand right, which we do have.

The doc is good, though if you wanted to accelerate with some sample tests cases of:
(1) a HelmRelease and
(2) a list of actual yaml files and kustomize commands to run it
(3) expected output
that could help make it easier for me to implement it.

[jkotiuk]

What I was thinking was to extend "helm template" command with --post-render ./kustomize argument

flux-local/flux_local/helm.py

Line 254 in 2f43392

args: list[str] = [

Extract patches from HelmRelease i.e patches=$(yq eval '[.spec.postRenderers[].kustomize.patches[]]' helmrelease.yaml)

Add kustomize that will be passed to --post-render

#!/bin/bash
cat <&0 > all.yaml

echo """apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - all.yaml
""" > kustomization.yaml

if [ -n "$patches" ]; then
  echo "patches:" >> kustomization.yaml
  echo "$patches" >> kustomization.yaml
fi

kustomize build .

then helm template test -n myns oci://registry-1.docker.io/bitnamicharts/nginx --post-renderer ./kustomize will render it

Sample HelmRelease I used for testing

apiVersion: helm.toolkit.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: nginx
spec:
  postRenderers:
  - kustomize:
      patches:
      - patch: |-
          - op: add
            path: /spec/template/spec/containers/0/env/-
            value:
              name: MYENV_NAME
              valye: myenv_value
        target:
          kind: Deployment
      - patch: |-
          - op: replace
            path: /spec/template/spec/containers/0/startupProbe
            value:
              failureThreshold: 10
              initialDelaySeconds: 30
        target:
          kind: Deployment
  - kustomize:
      patches:
      - patch: |-
          - op: replace
            path: /spec/revisionHistoryLimit
            value: 2
        target:
          kind: Deployment