https://github.com/noris-network/kustomize-generalreplacementstransformer

A kustomize transformer plugin
https://github.com/noris-network/kustomize-generalreplacementstransformer

go golang kubernetes kustomize plugin yaml

Last synced: about 2 months ago
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A kustomize transformer plugin

• Host: GitHub
• URL: https://github.com/noris-network/kustomize-generalreplacementstransformer
• Owner: noris-network
• License: apache-2.0
• Created: 2022-03-22T13:28:57.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2022-09-16T07:44:32.000Z (almost 4 years ago)
• Last Synced: 2024-12-29T17:53:38.802Z (over 1 year ago)
• Topics: go, golang, kubernetes, kustomize, plugin, yaml
• Language: Go
• Homepage:
• Size: 87.9 KB
• Stars: 1
• Watchers: 5
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# kustomize-generalreplacementstransformer

[![Go Report Card](https://goreportcard.com/badge/github.com/noris-network/kustomize-generalreplacementstransformer)](https://goreportcard.com/report/github.com/noris-network/kustomize-generalreplacementstransformer)

[![Latest Release](https://img.shields.io/github/v/release/noris-network/kustomize-generalreplacementstransformer?sort=semver)](https://github.com/noris-network/kustomize-generalreplacementstransformer/releases/latest)

[![License](https://img.shields.io/github/license/noris-network/kustomize-generalreplacementstransformer)](https://github.com/noris-network/kustomize-generalreplacementstransformer/blob/main/LICENSE)

## What is this for?

[Kustomize](https://github.com/kubernetes-sigs/kustomize) is a great tool

for deploying Applications following GitOps. But Sometimes you need to

change "things" that are not addressable with the build in

[replacements](https://kubectl.docs.kubernetes.io/references/kustomize/kustomization/replacements/).

That's where GeneralReplacementsTransformer comes into play. It's a kustomize

plugin that allows you to select values in a similar way than the build in

replacements, but uses golang template expressions wherever you need to insert

values. This is very powerful, but should definitely be used with care.

## Installation

The `GeneralReplacementsTransformer` binary can be downloaded from the

[GitHub releases page](https://github.com/noris-network/kustomize-generalreplacementstransformer/releases).

In order to be called by [kustomize](https://github.com/kubernetes-sigs/kustomize),

it has to be installed to `$XDG_CONFIG_HOME/kustomize/plugin/noris.net/v1alpha1/generalreplacementstransformer`.

(`$XDG_CONFIG_HOME` points by default to `$HOME/.config` on Linux and OS X, and `%LOCALAPPDATA%` on Windows.)

Install version 0.16.0 on Linux:

    VERSION=0.16.0 OS=linux ARCH=amd64

    INSTALL_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/kustomize/plugin/noris.net/v1alpha1/generalreplacementstransformer"

    curl -Lo GeneralReplacementsTransformer https://github.com/noris-network/kustomize-generalreplacementstransformer/releases/download/v${VERSION}/GeneralReplacementsTransformer_${VERSION}_${OS}_${ARCH}

    chmod +x GeneralReplacementsTransformer

    mkdir -p $INSTALL_DIR

    mv GeneralReplacementsTransformer $INSTALL_DIR

## Usage

Let's say you need a password in more than one place, but some locations are not

addressable by build in replacements, and you only want to define it once...

Create a kustomization.yaml file:

    cat <<. >kustomization.yaml

    apiVersion: kustomize.config.k8s.io/v1beta1

    kind: Kustomization

    namespace: demo

    secretGenerator:

      - name: mongodb-auth

        literals:

          - mongodb-root-password=secret123

      - name: mongodb-env

        literals:

          - MONGO_URL=mongodb://demo:{{.password}}@mongodb/demo

    transformers:

      - transformer.yaml

    .

    cat <<. >transformer.yaml

    apiVersion: noris.net/v1alpha1

    kind: GeneralReplacementsTransformer

    metadata:

      name: example

    selectValues:

      - name: password

        resource:

          kind: Secret

          name: mongodb-auth

          fieldPath: data.mongodb-root-password

    replacements:

      - resource:

          kind: Secret

          name: mongodb-env

        type: template

    .

    kustomize build --enable-alpha-plugins

It is of cause not recommended to put your secret data unencrypted into any files,

you could e.g. use [SopsSecretGenerator](https://github.com/goabout/kustomize-sopssecretgenerator)

to protect them. GeneralReplacementsTransformer will still work.

## Selecting Values

The `resource`-selector in `selectValues` supports `kind`, `name` and `fieldPath`.

## Loading Values

The transformer manifest can also load values from an external file defined in

`valuesFile`, see [examples](examples/transformer.yaml#L10). Secrets encrypted with

[SOPS](https://github.com/mozilla/sops) can be loaded with `secretsFile`, analog

to `valuesFile`. Values from `valuesFile` overwrite values given in `values`, values

from `secretsFile` overwrite values from `valuesFile`.

## Inserting Values

The `resource`-selector in `replacements` supports `kind` and `name`, which might

be empty to select multiple resources.

All string values in yaml content can contain golang template expressions, e.g.:

    key: "{{.value}}"

Values can contain template expressions, see

[examples -> values -> hostname](examples/transformer.yaml#L7-L8).

[Slim-sprig](https://go-task.github.io/slim-sprig/) functions are also available:

    key: "deployed at {{ now | date "2006-01-02 }}"

Right now just `type: template` is supported, this might change some time, but there

are no plans so far.

## Using GeneralReplacementsTransformer with ArgoCD

GeneralReplacementsTransformer can be added to ArgoCD by [patching](doc/argocd.md)

an initContainer into the ArgoCD provided `install.yaml`.