Moep90/agent-toolkit-for-kapitan

Rendering Helm charts with Kapitan

Kapitan renders Helm charts natively with input_type: helm. You declare the chart as a dependency (Kapitan fetches it) and a compile entry (Kapitan templates it with your values). The rendered manifests land in compiled/; you never vendor the chart or run helm yourself.

Two halves live under one parameters.<app> block, referenced by ${<app>:key} self-links so a value is written once.

Shape

parameters:
  cert-manager:
    chart_name: cert-manager
    chart_version: "v1.4.0"
    chart_dir: system/sources/charts/${cert-manager:chart_name}
    application_version: "v1.4.0"
    namespace: ${namespace}
    helm_values:
      installCRDs: true
      prometheus:
        enabled: true
  kapitan:
    dependencies:
      - type: helm
        output_path: ${cert-manager:chart_dir}
        source: https://charts.jetstack.io/
        version: ${cert-manager:chart_version}
        chart_name: ${cert-manager:chart_name}
    compile:
      - input_type: helm
        input_paths:
          - ${cert-manager:chart_dir}
        output_path: .
        helm_params:
          namespace: ${cert-manager:namespace}
          release_name: ${cert-manager:chart_name}
        helm_values: ${cert-manager:helm_values}

The two halves

• Dependency (type: helm) fetches the chart from source at version into output_path. It only runs when fetch is enabled, so the first compile of a target needs a fetch; later compiles reuse the fetched chart.
• Compile (input_type: helm) templates the fetched chart. helm_params.release_name and helm_params.namespace are the helm template flags; helm_values is the values document passed to the chart.

Key contract

chart_name, chart_version, namespace, and helm_values are the values you set; everything else references them with ${<app>:...}. Keep chart_dir pointing at where the dependency fetches, or the compile entry templates an empty directory and emits nothing.

Some inventories (especially omegaconf ones) wrap this whole block in a custom resolver so a single line expands to the dependency and compile entries, which makes charts duplicatable. The underlying contract is still the two halves above; see kapitan-omegaconf-resolvers for that reuse mechanism.

After editing

Compile and diff (kapitan_compile_diff) to review the rendered manifests. A chart bump is a chart_version change plus a re-fetch, never a hand-edit of compiled/.

Validated against

Kapitan 0.34 through 0.36 with Helm 3.