create temporary kubeconfig for bash session

bashrc_kubetmp

#--------------------------------------------------------------------------
#
# kubetmp - create temporary kubeconfig for bash session
#
# - to be sourced at start of interactive shell
#
#--------------------------------------------------------------------------
# Copyright 2021,2026 Michal Belica <https://beli.sk>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#--------------------------------------------------------------------------

KUBETMP_PATH="${HOME}/.kube/tmp"

__kubetmp_ns() {
	kubectl config view --minify -o jsonpath="{.contexts[0].context.namespace}"
	echo
}

_kubetmp_cleanup() {
	local tty=$(tty | tr / _)
	local configfile="${KUBETMP_PATH}/config.${tty}"
	unset KUBECONFIG
	[[ -f "$configfile" ]] && rm "$configfile" 2>/dev/null
	PS1=$( echo "$PS1" | sed -r 's/(.*)\(ns:[^)]*\)\)(.*)/\1\2/' )
}

kubetmp() {
	local version="0.0.5"
	local context
	local namespace
	local tty=$(tty | tr / _)
	local configfile="${KUBETMP_PATH}/config.${tty}"

	[[ ! -d "$KUBETMP_PATH" ]] && mkdir -p "$KUBETMP_PATH"

	if [[ -z "$1" ]] ; then
		context=""
		namespace=""
	elif [[ "$1" == "c" || "$1" == "ctx" || "$1" == "context" ]] ; then
		context="$2"
		namespace="$3"
	elif [[ "$1" == "n" || "$1" == "ns" || "$1" == "namespace" ]] ; then
		context=""
		namespace="$2"
	elif [[ "$1" == "x" || "$1" == "exit" ]] ; then
		context=""
		namespace=""
		_kubetmp_cleanup
		return
	elif [[ "$1" == "version" ]] ; then
		echo "kubetmp version $version"
		echo ''
		echo 'Copyright 2021,2026 Michal Belica <https://beli.sk>'
		echo ''
		echo 'Licensed under the Apache License, Version 2.0 (the "License");'
		echo 'you may not use this file except in compliance with the License.'
		echo 'You may obtain a copy of the License at'
		echo ''
		echo '    http://www.apache.org/licenses/LICENSE-2.0'
		echo ''
		echo 'Unless required by applicable law or agreed to in writing, software'
		echo 'distributed under the License is distributed on an "AS IS" BASIS,'
		echo 'WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.'
		echo 'See the License for the specific language governing permissions and'
		echo 'limitations under the License.'
		echo ''
		return
	else
		echo 'use: kubetmp [command] [args...]'
		echo
		echo 'commands:'
		echo '  create temporary kubeconfig with specified context and/or namespace:'
		echo '    context|ctx|c <context> [namespace]'
		echo '    namespace|ns|n <namespace>'
		echo '    (no command or args uses current context and namespace)'
		echo '  special commands:'
		echo '    exit -- reset and delete temporary config'
		echo '    version -- show version information'
		echo '    help -- show this text'
		echo
		return
	fi
	PS1=$( echo "$PS1" | sed -r 's/(.*)\(ns:[^)]*\)\)(.*)/\1\2/' )
	if [[ "$KUBECONFIG" != "$configfile" || -n "$context" ]] ; then
		unset KUBECONFIG
		[[ -n "$context" ]] && kubectl config use-context "$context"
		touch "$configfile"
		chmod 0600 "$configfile"
		kubectl config view --flatten --minify > "$configfile"
		export KUBECONFIG="$configfile"
	fi
	[[ -n "$namespace" ]] && kubectl config set-context --current --namespace="$namespace"
	PS1='(ns:$(__kubetmp_ns))'"${PS1}"
}

_kubetmp_completions() {
	local kcbackup="$KUBECONFIG"
	local words cword
	cword="${COMP_CWORD}"
	words=("${COMP_WORDS[@]:0:$cword+1}")
	if [[ "${#words[@]}" == "2" ]] ; then
		COMPREPLY=($(compgen -W "context namespace exit version help" -- "${words[1]}"))
	elif [[ "${#words[@]}" == "3" ]] ; then
		if [[ "${words[1]}" == "n" || "${words[1]}" == "ns" || "${words[1]}" == "namespace" ]] ; then
			COMPREPLY=($(compgen -W "`kubectl get ns -o jsonpath='{.items[*].metadata.name}'`" -- "${words[2]}"))
		elif [[ "${words[1]}" == "c" || "${words[1]}" == "ctx" || "${words[1]}" == "context" ]] ; then
			COMPREPLY=($(compgen -W "`KUBECONFIG= kubectl config view -o jsonpath='{.contexts[*].name}'`" -- "${words[2]}"))
		fi
	elif [[ "${#words[@]}" == "4" ]] ; then
		if [[ "${words[1]}" == "c" || "${words[1]}" == "ctx" || "${words[1]}" == "context" ]] ; then
			unset KUBECONFIG
			COMPREPLY=($(compgen -W "`kubectl --context=${words[2]} get ns -o jsonpath='{.items[*].metadata.name}'`" -- "${words[3]}"))
			export KUBECONFIG="$kcbackup"
		fi
	fi
}

complete -F _kubetmp_completions kubetmp
alias ktmp=kubetmp
complete -F _kubetmp_completions ktmp
_kubetmp_cleanup