ded

Helm dependency deduplication post-renderer

Installation

pip install ded

Usage

This program collects all pre-rendered manifests from Helm and post-renders only those unique amongst them.

The uniqueness is determined based on the default or supplied YAML keys. The keys must exist in all of the supplied documents.

Invoke as --post-renderer during helm install/upgrade.

ded determines uniquiness based on values of the kind and metadata.name fields of each manifests. You can specify non-default keys by which the pre-rendered manifests from helm must be deduplicated:

  ded --key metadata.namespace

IMPORTANT: The keys used to determine uniquiness must be present in every manifest or ded will exit with code 1 and helm install or helm upgrade will consequently fail.

Examples

The example below will filter all manifests based on values of kind and metadata.name fields.

helm install release-name your-chart/ --post-renderer ded

So, if there are 2 manifests in your Helm chart release with the same values on these fields, then only one of them will be left.

Manifest A:

apiVersion: v1
kind: ConfigMap
metadata:
  name: foo-cm
data:
  onedata: test

Manifest B:

apiVersion: v1
kind: ConfigMap
metadata:
  name: foo-cm
data:
  twodata: test-test

In the example above only the first occuring manifest will make it to the output of the post-renderer.

Or invoke with a different set of keys:

helm install release-name your-chart/ --post-renderer ded --key metadata.name

More keys:

helm install release-name your-chart/ --post-renderer ded -k metadata.name --k data.onedata

Why ded?

1. Because it's a shorthand for deduplication
2. Because "ded" means grandpa in Russian. And I was grumpy as hell when I was trying to deduplicate manifests generated by Helm.
3. Because dealing with subcharts and dependencies in Helm makes you a little dead inside.

Helm is ❤️