# Kubernetes Configuration Templates

This directory contains Jsonnet templates that define reusable application configurations. Many of these templates wrap Helm charts.

## Creating a Template for a Helm Chart

To create a template that wraps a Helm chart:

1.  **Ensure the Chart is Available:**
    *   Add the chart to `third_party/helm/chartfile.yaml`.
    *   Run `bazel run //tools:helm_sync` to update the lockfile.
    *   Add the generated repository name (e.g., `helm_jetstack_cert_manager`) to `MODULE.bazel` in the `helm_deps` `use_repo` list.

2.  **Create the Libsonnet File:**
    *   Import `base.libsonnet`.
    *   Define a `Params` struct.
    *   Define an `App` function that calls `params.context.helm.template`.
    *   **Path Resolution:** The `chartPath` passed to `helm.template` must be relative to the *caller* (this libsonnet file) and point to the external repository. In the Bazel sandbox, this usually looks like `../../external/+helm_deps+repo_name`.

    ```jsonnet
    local base = import "k8s/configs/base.libsonnet";

    local Params = base.SimpleFieldStruct(["namespace", "name", "context", "values"]);

    local App(params) = {
        local chartPath = "../../external/+helm_deps+my_chart_repo",
        app: params.context.helm.template(params.name, chartPath, {
            namespace: params.namespace,
            values: params.values,
        })
    };

    { Params: Params, App: App }
    ```

3.  **Update `BUILD.bazel`:**
    *   Ensure the `jsonnet_library` target in this directory includes the new file.
    *   In the environment's `BUILD.bazel` (e.g., `k8s/configs/environments/my-app/BUILD.bazel`), add the chart's filegroup to the `data` attribute of `jsonnet_to_json`.

    ```python
    jsonnet_to_json(
        name = "main",
        ...
        data = [
            "@helm_deps_my_chart_repo//:chart",
        ],
    )
    ```

## Import Paths

When importing `tanka-util` or other external libraries, use the path relative to the repository root. `rules_jsonnet` configured with `deps` adds the repository root to the import path.

Example:
```jsonnet
local tanka = import "tanka-util/main.libsonnet";
```
(Assuming `tanka-util` directory is at the root of the dependency).