README

This document describes Bash functions included in the repository. Functions are meant to automate repetitive operations in situations, when same change has to be applied to a similar resources in multiple Kubernetes clusters in the abscense of the up-to-date configuration files describing current state of this resources. Especially good for complex custom resources ~500 lines long (wink wink). Each function was made to be usable, and probably even useful, on its own.

Dependencies

• fzf: a command-line fuzzy finder. See https://github.com/junegunn/fzf
• yq: a command-line YAML processor. See https://github.com/mikefarah/yq
• yaml-diff, yaml-validate, yaml-merge: a command-line tools from YAML Path project. See https://github.com/wwkimball/yamlpath/wiki/Command-Line-(CLI)-Tools
• kubectl: the Kubernetes command-line tool. It must be installed and configured with access to a Kubernetes cluster.
• kustomize: a command-line tool used to customize Kubernetes objects. See https://kubectl.docs.kubernetes.io/installation/kustomize/

Installation :D

1. Install dependancies listed above and those which are not listed, as you will probably discover, because I forgot them or you use something which is not Ubuntu 22.04
2. Clone repo, go to the dir and source the file with source kytools.sh

Additionally to use kysyncmerge(), kymerge(), kyindent() you have to:

4. Create ~/yamlpath dir
5. In the ~/yamlpath dir create mergepaths.txt with at least one line which consist of a dot .. This is a file with the list of YAML paths indicating where in the source file your change is to be merged, where . mean top of the YAML file
6. In the ~/yamlpath dir create yaml file or files describing your desired changes to the Kubernetes resources

Few examples of yamlpath dir contents are included, so instead of creating it can be copied to ~/yamlpath.

Description

kysyncmerge()

The kysyncmerge is a simple combination of the other functions mentioned here. It saves the interactively selected resource from the Kubernetes cluster to a local YAML file using the kysync, then merges the interactively selected changes using kymerge function. It then removes fields using the kyclean, and finally indents the resulting YAML file using the kyindent.

It provides a way to generate the modified and validated YAML file from existing Kubernetes resource with one command. Generated file is then ready to be saved to a version control system or applied back to the previously selected resource in the Kubernetes cluster with kubectl apply -f FILEPATH.

Usage:

kysyncmerge [--file=FILEPATH]

• --file=FILEPATH (optional): The path to save the live Kubernetes object. If not specified, fselect() will be used to select a file interactively. The same file path will be used for all operations.

fselect()

fselect() is a Bash function that allows interactive selection of a file using fzf. It excludes hidden files/directories and displays file contents in fzf preview. If no file is selected, it returns an error message.

Usage:

fselect [path]

• path (optional): The path to search for files. If not specified, the current directory is used.

kg()

kg() is a Bash function that simplifies the process of selecting and retrieving Kubernetes resources. It uses kubectl to retrieve a list of resource types and namespaces, and then uses fzf to allow interactive selection of the resource and namespace. If no resource or namespace is selected, it returns an error message.

Usage:

kg [kubectl arguments]

• kubectl arguments (optional): Any arguments, apart from resource type, name and namesapce, that would normally be passed to kubectl get. For example: kg -o yaml or kg --show-labels will work fine.

kydiff()

kydiff() is a Bash function that compares a local YAML file to a live Kubernetes object, using yaml-diff. It prompts the user to select a live object from the cluster interactively using kg(), and a local YAML file using fselect(), if it was not provided as parameter. It then displays the differences between the two YAML representations, and validates the local YAML file using yaml-validate and kubectl diff.

Usage:

kydiff [--file=FILEPATH]

• --file=FILEPATH (optional): The path to the local YAML file to be compared. If not specified, fselect() will be used to select a file interactively.

kysync()

The kysync function synchronizes a Kubernetes object from the cluster to a file. It prompts the user to select a live object from the cluster interactively using kg(), and a local YAML file using fselect(), if it was not provided as parameter. It saves the live object from the cluster to a YAML file specified as a parameter or interactively selected.

Usage:

kysync [--file=FILEPATH]

• --file=FILEPATH (optional): The path to save the live Kubernetes object. If not specified, fselect() will be used to select a file interactively.

kymerge()

The kymerge() function merges a YAML file containing changes with a source YAML file using yaml-merge utility. It prompts the user to provide a source file, a file containing changes, and a YAML path indicating where in the source file the change is to be merged. If any of these values are not provided as parameters, the user is prompted to select the files interactively using fselect(). If the mergepath parameter is not provided, the user is prompted to select a YAML path interactively using fzf.

Usage:

kymerge [--file=SOURCE_FILEPATH] [--change=CHANGE_FILEPATH] [--mergepath=YAML_PATH]

• --file=SOURCE_FILEPATH (optional): The path to the source YAML file. If not specified, fselect() will be used to select the file interactively.
• --change=CHANGE_FILEPATH (optional): The path to the YAML file containing the required changes. If not specified, fselect() will be used to select the file interactively.
• --mergepath=YAML_PATH (optional): The YAML path indicating where in the source file the change is to be merged. If not specified, fzf will be used to select the path interactively.

The function performs merging using yaml-merge and saves the resulting YAML file to the source file path provided. It then validates the resulting YAML file using yaml-validate and kubectl diff. If any of the steps fail, the function returns with exit code 1.

The tmppath variable is used to store the temporary path for merging and is set to ~/yamlpath by default.

tmppath=~/yamlpath

kyclean()

The kyclean function removes the non-essential parts of a Kubernetes object YAML file to make it suitable for editing, version control, or sharing. The removed parts include .status, .metadata.uid, .metadata.generation, and .metadata.creationTimestamp. The function prompts the user to select a YAML file interactively using fselect(), if it was not provided as parameter.

Usage:

kyclean [--file=FILEPATH]

• --file=FILEPATH (optional): The path to the Kubernetes object YAML file. If not specified, fselect() will be used to select a file interactively.

kyindent()

!!! Required as a temporary workaround to fix indentation of resulted files

The kyindent function applies "Kubernetes-style" indentation to a YAML file with the help of kubectl kustomize. It prompts the user to select a YAML file interactively using fselect() if it was not provided as parameter. The indentation is performed by creating a temporary directory with a unique name to avoid overwriting existing files, creating a temporary kustomization.yaml file in the temporary directory, and populating it with the path to the YAML file. Finally, kubectl kustomize is used to perform the indentation. The temporary directory and files are then removed.

Usage:

kyindent [--file=FILEPATH]

• --file=FILEPATH (optional): The path to the YAML file to be indented. If not specified, fselect() will be used to select a file interactively.

The tmppath variable is used to store the temporary files and is set to ~/yamlpath by default.

tmppath=~/yamlpath