Git credential-helper to supply $GITHUB_TOKEN to github auth

git-credential-githubenv

#!/bin/bash
set -euo pipefail

###
# How to use?
#
# - Download into path with name `git-credential-githubenv`
# - Enable helper `git config --global credential.helper 'githubenv'`
# - Expose corresponding token as `GITHUB_TOKEN` env variable
#
# Pay attention: Credentials in ENV variables is a bad idea on insecure
# or shared systems. If anyone can anyhow access your system, they can
# access your env variables! So use with care and don't blame me if
# things have gone very wrong.
###

action=${1:-invalid}
case ${action} in

get) ;; # Only supported action
*)
	echo "Action not supported: ${action}" >&2
	exit 1
	;;

esac

[[ -n ${GITHUB_TOKEN:-} ]] || exit 1

declare -A input

while read LINE; do

	[[ -n ${LINE} ]] || break

	key=$(echo "${LINE}" | cut -d '=' -f 1)
	value=$(echo "${LINE}" | cut -d '=' -f 2-)

	input[$key]=$value

done

[[ ${input["protocol"]} == "https" ]] && [[ ${input["host"]} == "github.com" ]] || exit 1

for k in ${!input[@]}; do
	echo "${k}=${input[$k]}"
done

echo "username=api"
echo "password=${GITHUB_TOKEN}"