Helm Template If/Else

External

• https://helm.sh/docs/chart_template_guide/control_structures/#if-else

Internal

• Helm Templates

Overview

if/else can be used to create conditional blocks.

The if control structures evaluate pipelines, not just values (values are a special case of a pipeline):

{{ if PIPELINE }}
  # Do something
{{ else if OTHER_PIPELINE }}
  # Do something else
{{ else }}
  # Default case
{{ end }}

A pipeline evaluates to false if the result of the pipeline, or the value, is:

• a boolean false
• a numeric zero
• an empty string
• a nil (empty or null)
• an empty collection (map, slice, tuple, dict, array).

In any other case, the condition is evaluated to true.

Example:

{{ if .Values.debug }}
  # Do something
{{ else }}
  # Do something else
{{ end }}

Expression

if expressions are built with functions: eq, ne, lt, gt, and, or, so the function name is provided first, followed by the arguments. Functions can be grouped with ( ).

Testing the Existence of Two Configuration Elements in the Same Expression

{{- if or .Values.myApp.config.local .Values.myApp.config.nfs }}
   ...
{{- end }}

Testing the Non-Existence of a Configuration Element

The following conditional evaluates to true and the embedded content is rendered if the configuration element does NOT exist:

{{- if not .Values.myApp.something }}
... 
{{- end }}

Testing Equality and Inequality of Values

{{- if eq .Values.myApp.color "blue" }}
... 
{{- end }}

{{- if ne .Values.myApp.color "blue" }}
... 
{{- end }}

{{- if eq .Values.myApp.something .Values.myApp.somethingElse }}
... 
{{- end }}

{{- if and (eq .Values.myApp.color "blue") (eq .Values.myApp.shape "square") }}
... 
{{- end }}

Interesting Links

• https://stackoverflow.com/questions/49789867/can-we-use-or-operator-in-helm-yaml-files