Managing Kubernetes Resources Using Helm Second Edition by Andrew Block | Austin Dewey

Author:Andrew Block | Austin Dewey
Language: eng
Format: epub
Publisher: Packt Publishing Pvt Ltd
Published: 2022-09-09T00:00:00+00:00

There are occasions where portions of a template would need to be included or excluded based on some sort of condition. In this situation, an if/else action can be used. Here is a basic example for conditionally determining whether to include a readiness probe as part of a deployment resource:

{{- if .Values.readinessProbe.enabled }} readinessProbe: httpGet: path: /healthz port: 8080 scheme: HTTP initialDelaySeconds: 30 periodSeconds: 10 {{- end }}

The readinessProbe section will only be included when the condition evaluates to true. However, it is important to note that the condition is actually a pipeline where multiple statements can be chained together to aid in the creation of complex conditionals. The logic behind the if/else action can also be interpreted as follows:

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

The conditional statements and their associated if/else action should look familiar to anyone with prior programming experience. But what is the logic behind determining whether a pipeline is true or false?

A pipeline fails to evaluate to true when the following is returned:

A false Boolean

A numeric 0

An empty string

nil (whether it be empty or null)

An empty collection

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