kubectl-shell_ctx

#!/bin/bash
# Kubernetes shell independent context switching
# Version: 1.0.14

set -eou pipefail

if [[ "$(basename "$0")" == kubectl-* ]]; then # we are invoked as plugin
	SELF="kubectl shell-ctx"
else
	SELF="shell-ctx"
fi

err() {
  echo "Error, $*" 1>&2
  exit 1
}

usage() {
	cat <<-EOF
	Usage:
	  $SELF                       : Select new context
	  $SELF clone                 : Clone context from another shell
	  $SELF hook <SHELL>          : Hook for <SHELL>
	  $SELF -h,--help             : Show this message

	Setup:
	  $(do_help_hook)
	EOF
}

do_help_hook() {
  cat <<-EOF
	Setup is required for $SELF to function correctly.

	#################################################################################
	# IMPORTANT:                                                                    #
	#  If you are setting a custom KUBECONFIG                                       #
	#  you need to do that BEFORE loading the shell hook!                           #
	#################################################################################

	  BASH: append the following to your ~/.bashrc:

		eval "\$($(basename "$0") hook bash)"


	  ZSH: append the following to your ~/.zshrc:

		eval "\$($(basename "$0") hook zsh)"


	  FISH: append the following to your ~/.config/fish/config.fish:

		$(basename "$0") hook fish | source

  
	EOF
}

do_hook() {
	# Setup tmp KUBECONFIG for this shell

	if [ -z ${KUBECONFIG+x} ]; then
		KUBECONFIG=""
	fi

	if [ -z ${KUBECTL_SHELL_CTX_DIR+x} ]; then
		KUBECTL_SHELL_CTX_DIR="/tmp"
	fi

	local TMP_KUBECONFIG
	TMP_KUBECONFIG=$(mktemp -q "${KUBECTL_SHELL_CTX_DIR}"/kubectl-shell-ctx.XXXXXX || exit 1)

	if [[ "$1" == "bash" ]] || [[ "$1" == "zsh" ]]; then
		echo "export KUBECONFIG=$TMP_KUBECONFIG"
		echo "export KUBECTL_SHELL_CTX_HOOK=$1"
		echo "trap \"rm -f -- $TMP_KUBECONFIG\" EXIT"
	elif [[ "$1" == "fish" ]]; then
		echo "set -x KUBECONFIG $TMP_KUBECONFIG"
		echo "set -x KUBECTL_SHELL_CTX_HOOK $1"
		echo "trap \"rm -f -- $TMP_KUBECONFIG\" EXIT"
	else
		err "Unknown shell $1"
	fi

	# Write current context to new temp context
	( 
		local NEW_KUBECONFIG_CONTENT
		NEW_KUBECONFIG_CONTENT=$($KUBECTL config view --raw)

		# Create new kubeconfig for this shell
		echo "$NEW_KUBECONFIG_CONTENT" >"$TMP_KUBECONFIG"
		chmod 600 "$TMP_KUBECONFIG" 
	) &

}

do_clone() {
	if [ -z ${KUBECTL_SHELL_CTX_DIR+x} ]; then
		KUBECTL_SHELL_CTX_DIR="/tmp"
	fi

	# Find other shell-ctx instances
	SHELL_CTXS=$(find "${KUBECTL_SHELL_CTX_DIR}"/ -type f -name "kubectl-shell-ctx*" -not -name "$(basename "$KUBECONFIG")" 2>/dev/null || true)
	[[ -z "$SHELL_CTXS" ]] && err "no other shell-ctx instances found"
	for SHELL_CTX in $SHELL_CTXS; do
		local TMP_CTX_CONTEXT
		TMP_CTX_CONTEXT=$(KUBECONFIG=$SHELL_CTX $KUBECTL config current-context || echo "No current context")
		TMP_CTX+="$SHELL_CTX	$TMP_CTX_CONTEXT\n"
	done
	SELECTED_CTX=$(echo -e "$TMP_CTX" | fzf -e --no-sort --border=top --border-label='Select context to clone' $FZF_STYLE_ARG --layout=reverse --pointer='▶' --marker='✓' --info=inline --cycle --height=~80% --prompt='Search: ' --color='label:cyan,prompt:cyan' | awk '{print $1}')
	cp -rp "$SELECTED_CTX" "$KUBECONFIG"
}

main() {
	if [[ -z "${KUBECTL:-}" ]]; then
		if hash kubectl 2>/dev/null; then
			KUBECTL=kubectl
		elif hash kubectl.exe 2>/dev/null; then
			KUBECTL=kubectl.exe
		else
			err "Error, kubectl is not found"
		fi
	fi

	if [[ "$#" -eq 2 ]] && [[ "$1" == 'hook' ]]; then
		do_hook "$2"
	elif [[ "$#" -eq 0 ]]; then
		# Check we have the hook setup
		if [[ -z "${KUBECTL_SHELL_CTX_HOOK:-}" ]]; then
			do_help_hook
		else
			checkRequirements
			if command -v yq &>/dev/null; then
				PREVIEW_CMD="$KUBECTL --context {} config view --minify | yq -C"
			else
				PREVIEW_CMD="$KUBECTL --context {} config view --minify"
			fi
			SELECTED_CTX="$($KUBECTL config get-contexts --no-headers=true -o name | sed 's/^\*/ /g' | fzf -e --no-sort --border=top --border-label='Select context' $FZF_STYLE_ARG --layout=reverse --preview="$PREVIEW_CMD" --preview-window=right,60%,border-rounded,wrap --pointer='▶' --marker='✓' --info=inline --cycle --height=~80% --prompt='Search: ' --color='label:cyan,prompt:cyan')"
			$KUBECTL config use-context "$SELECTED_CTX"
		fi
	elif [[ "$#" -eq 1 ]] && [[ "$1" == "clone" ]]; then
		checkRequirements
		do_clone
	elif [[ "$#" -eq 1 ]] && [[ "$1" == '-h' ]] || [[ "$1" == '--help' ]]; then
		usage
	elif [[ "$#" -eq 1 ]]; then
		# Use context supplied on command line
		$KUBECTL config use-context "$1"
	else
		echo "Error, unknown commandline arguments"
		usage
		exit 1
	fi
}

checkRequirements() {
	# Test for requirements
	REQUIREMENTS="mktemp awk sed fzf kubectl"
	for REQUIREMENT in $REQUIREMENTS; do
		command -v "$REQUIREMENT" 1>/dev/null || {
			err "requirement missing: $REQUIREMENT"
		}
	done
	# Check fzf version (--style=full requires 0.58+)
	checkFzfVersion
}

checkFzfVersion() {
	local FZF_VERSION
	FZF_VERSION=$(fzf --version | awk '{print $1}' | cut -d. -f1-2)
	local MAJOR
	local MINOR
	MAJOR=$(echo "$FZF_VERSION" | cut -d. -f1)
	MINOR=$(echo "$FZF_VERSION" | cut -d. -f2)
	
	# --style=full requires fzf 0.58+
	if [[ $MAJOR -eq 0 ]] && [[ $MINOR -lt 58 ]]; then
		FZF_STYLE_ARG=""
	else
		FZF_STYLE_ARG="--style=full"
	fi
}

main "$@"