Helm template: Array to a comma separated string

helm template array comma separated

2 min read | by Jordi Prats

While writing Helm charts we might need to transform some values that are going to be defined as an array as a value into a comma separated string

Let's assume we have the following values defined:

application:  defaultRegions:  - name: eu-west-1  - name: us-west-1

If we need to tranform this array into a string we can use the join function:

  • It's first argument is the separator, in this example we are going to use a comma, but it can be any string
  • The second argument is the array we want to join

This is an example on how to use it:

(...) apiVersion: v1 kind: Pod metadata: (...)  initContainers:  - command:  - applicacion  - config   - '--regions'  - '{{ join "," .Values.application.defaultRegions }}'  env: (...)

It's output would looks like this (we can use helm template or the --dry-run option to render the objects)

(...) apiVersion: v1 kind: Pod metadata: (...)  initContainers:  - command:  - applicacion  - config   - '--regions'  - 'eu-west-1,us-west-1'  env: (...)

Posted on 12/11/2021

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