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Useful Tools

YQ: Handy CLI to Parse YAML

yq is a lightweight command-line utility to parse YAML. But wait, there’s more!

Not just YAML, yq also works with JSON, XML, LUA, Shell output, and properties files.

Also written in Go

Project: github.com/mikefarah/yq

Handles almost all file types you’ll encounter in CI/CD pipelines. Perfect for those times when you need to tweak files on the fly.

Here is one use case.

Pair yq with kustomize to patch values directly into your YAML files.

For instance, read an image name from an environment variable and add it to the YAML.

Usage Example

Let’s take an example of pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: my-nginx-pod
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.14.2
    ports:
    - containerPort: 80

To get the apiVersion

yq eval '.apiVersion' pod.yaml

To change the image name

yq eval -i '.spec.containers[0].image = "nginx:1.18"' pod.yaml