Open the door to including the images list on the Chart.lock file

Signed-off-by: Pablo Caraballo Llorente <[email protected]>

hips/hip-0019.md

@@ -107,6 +107,44 @@ This file should be distributed either alongside or within the Helm Chart being
 
 In addition to this, if the chart lock is available, then we could create a Helm builtin object called `Images`, just like we have `Chart` or `Release`. This would be useful for generating the template YAML and therefore avoid having the image information replicated in the lock and the values.yaml file.
 
+Alternatively to the `images-lock.yml` file, this bill of materials could live inside the existing `Chart.lock`. While this reuses an existing file, which in part is intended to accomodate these kind of metadata, it also implies that a packaged chart may bundle different code than the original (i.e. if we took Bitnami's [Wordpress](https://github.com/bitnami/charts/blob/main/bitnami/wordpress/Chart.lock) and packaged it, the resulting `Chart.lock` would be different to the original). Yet, this could be addressed by tracking the `Chart.lock` file with images in `git`, or by not tracking it at all (like other users may do). This is a debate it already exists for other package managers and that has been out there for a while. A minimalistic draft of the `Chart.lock` file could be as follows:
+
+```yaml
+dependencies:
+- name: memcached
+  repository: https://charts.bitnami.com/bitnami
+  version: 6.3.2
+- name: mariadb
+  repository: https://charts.bitnami.com/bitnami
+  version: 11.4.1
+- name: common
+  repository: https://charts.bitnami.com/bitnami
+  version: 2.2.2
+digest: sha256:5a55c2b684433bf6fa9efcf0d3c4ab23ceef313808203b766c485b6e03bda60f
+generated: "2022-12-13T02:28:18.307577267Z"
+images:
+  - name: wordpress
+    image: docker.io/bitnami/wordpress:6.0.2-debian-11-r9
+    digests: 
+      - digest: sha256:b4cb055a643d1d51d1678f3e011cf008b227852bc0a4118126deeed844ccfb6a
+        arch: linux/amd64
+      - digest: sha256:4d2760961bdd2e9956d752d637e7795e2eea973c25825bd18cb881c3edeee8ff
+        arch: linux/arm64
+    chart: wordpress
+  - name: bitnami-shell
+    image: docker.io/bitnami/bitnami-shell:11-debian-11-r37
+    digests: 
+      - digest: sha256:0946f1d16c010bed0a47e3c09ff193d898c868044bb4c1b037c83b7c53c26deb
+        arch: linux/amd64
+    chart: wordpress
+  - name: apache-exporter
+    image: docker.io/bitnami/apache-exporter:0.11.0-debian-11-r42
+    digests: 
+      - digest: sha256:ea4aa97834500297e4252f5f98492c52a7bfd1993bd5ef4e485ae84996b1c63a
+        arch: linux/amd64
+    chart: wordpress
+```
+
 ## Backwards compatibility
 
 There isn't any backward incompatibility, since there's no modification of any existing schema. Charts making use of the `annotations` and `images-lock` file would benefit of the feature, others just wouldn't.