gh-ssh

#!/bin/bash
# Description: Lightweight utility for managing SSH keys for multiple GitHub repositories
# Author: Leo Sandström <leo@sandstrom.party>

SSH_ROOT_DIR="$HOME/.ssh"
SSH_CI_DIR="$SSH_ROOT_DIR/github"
SSH_KEY_FILENAME="id_ed25519"
SSH_CONFIG_PATH="$SSH_ROOT_DIR/config"
SCRIPT_NAME=$(basename "${BASH_SOURCE[0]}")

set -Eeo pipefail
trap cleanup SIGINT SIGTERM ERR EXIT

IFS_OLD=$IFS

cleanup() {
  trap - SIGINT SIGTERM ERR EXIT
}

setup_colors() {
  if [[ -t 2 ]] && [[ -z "${NO_COLOR-}" ]] && [[ "${TERM-}" != "dumb" ]]; then
    NOFORMAT='\033[0m' DIM='\033[2m' UNDERLINE='\033[4m' BOLD='\033[1m' LIGHTGRAY='\033[0;37m' DARKGRAY='\033[0;90m' RED='\033[0;31m' LIGHTRED='\033[0;91m' GREEN='\033[0;32m' ORANGE='\033[0;33m' BLUE='\033[0;34m' PURPLE='\033[0;35m' PINK='\033[0;95m' CYAN='\033[0;36m' LIGHTYELLOW='\033[1;93m' YELLOW='\033[1;33m'
  else
    NOFORMAT='' DIM='' UNDERLINE='' BOLD='' LIGHTGRAY='' DARKGRAY='' RED='' LIGHTRED='' GREEN='' ORANGE='' BLUE='' PURPLE='' PINK='' CYAN='' LIGHTYELLOW='' YELLOW=''
  fi
}

print_cmd() {
	printf "${PINK}${BOLD}%s${NOFORMAT}" "$@"
}

print_param() {
	printf "${PURPLE}%s${NOFORMAT}" "$@"
}

print_path() {
	printf "${UNDERLINE}%s${NOFORMAT}" "$@"
}

print_link() {
	printf "${CYAN}${UNDERLINE}%s${NOFORMAT}" "$@"
}

fatal() {
	echo -e "${RED}$@${NOFORMAT}" 1>&2
	kill $$
}

warn() {
	echo -e "${ORANGE}⚠ $@${NOFORMAT}"
}

success() {
	echo -e "${GREEN}✓ $@${NOFORMAT}"
}

get_project_path() {
	local project_name="$1"
	local path="$SSH_CI_DIR/$project_name"

	echo "$path"
}

does_project_exist() {
	local project_name="$1"
	local project_path=$(get_project_path "$project_name")

	if [[ -d $project_path ]]; then
		return 0
	fi

	return 1
}

get_project_username() {
	local project_name="$1"

	# Split the input based on the delimiter
	IFS='/'
	read -a list <<< "$project_name"
	local count="${#list[*]}"
	IFS=$IFS_OLD

	# If the input matches our format
	if [ $count -eq 2 ]; then
		echo "${list[0]}"
	else
		exit 1
	fi
}

get_project_repository() {
	local project_name="$1"

	# Split the input based on the delimiter
	IFS='/'
	read -a list <<< "$project_name"
	local count="${#list[*]}"
	IFS=$IFS_OLD

	# If the input matches our format
	if [ $count -eq 2 ]; then
		echo "${list[1]}"
	else
		exit 1
	fi
}


get_project_public_key_path() {
	local project_name="$1"
	local project_path=$(get_project_path "$project_name")

	if [[ ! -d $project_path ]]; then
		exit 1
	fi

	local public_key_path=$(find $project_path -name "*.pub")

	if [ ! -f "$public_key_path" ]; then
		exit 1
	fi

	echo "$public_key_path"
}

get_project_private_key_path() {
	local project_name="$1"
	local public_key_path=$(get_project_public_key_path "$project_name")
	local private_key_path=${public_key_path%".pub"}

	if [ ! -f "$private_key_path" ]; then
		exit 1
	fi

	echo $private_key_path
}



get_project_public_key() {
	local project_name="$1"
	local path="$(get_project_public_key_path "$project_name")"

	echo $(<"$path")
}

get_project_private_key() {
	local project_name="$1"
	local path="$(get_project_private_key_path "$project_name")"

	echo $(<"$path")
}

get_project_ssh_hostname() {
	local project_name="$1"
	local username=$(get_project_username "$project_name")
	local repository=$(get_project_repository "$project_name")

	if [[ -z $username || -z $repository ]]; then
		exit 1
	fi

	echo "${username}_${repository}"
}

get_projects() {
	local username_folders=$(find "$SSH_CI_DIR" -mindepth 1 -maxdepth 1 -type d)

	for username_folder in ${username_folders[@]}; do
		local project_folders=$(find "$username_folder" -mindepth 1 -maxdepth 1 -type d)
		local username=$(basename $username_folder)

		for repository_folder in ${project_folders[@]}; do
			local repository=$(basename $repository_folder)
			local project="$username/$repository"

			echo $project
		done
	done
}

list_projects() {
	# Find all existing projects
	local projects="$(get_projects)"

	# Create the table header
	local rows="$(printf "${BOLD}%s|%s|%s|%s|%s|%s${NOFORMAT}\n" "REPOSITORY" "ACTIVE" "PRIVATE KEY" "PUBLIC KEY" "LAST UPDATED")\n"

	for project_name in $projects; do
		local repository="$(get_project_repository "$project_name")"
		local public_key_path="$(get_project_public_key_path "$project_name")"
		local private_key_path="$(get_project_private_key_path "$project_name")"

		# Skip if we couldn't find a public key
		if [ -z "$public_key_path" ]; then continue; fi

		local public_key_filename=$(basename "$public_key_path")
		local private_key_filename=$(basename "$private_key_path")

		# skip if we couldn't find a private key
		if [ -z "$private_key_filename" ]; then continue; fi

		# Check if the key exists in .ssh/config
		local active="${RED}No${NOFORMAT}"
		if grep -Fq "IdentityFile=${private_key_path}" $SSH_CONFIG_PATH; then active="${GREEN}Yes${NOFORMAT}"; fi

		# Check when the keys was last updated
		local last_changed=$(stat $public_key_path -c '%Z')

		# Make the date human readable
		local date=$(date -d "@$last_changed" +"%a %b %d %T %Y")

		# Append row to our table
		rows="${rows}$(printf "%s|%s|%s|%s|%s|%s|%s|%s\n" \
			"$CYAN${project_name}$NOFORMAT" \
			"$active" \
			"$DIM$private_key_filename$NOFORMAT" \
			"$DIM$public_key_filename$NOFORMAT" \
			"$date")\n"
	done

	echo -e $rows | column -t -s '|'
}

print_usage() {
	local script_name="${DARKGRAY}$DIM\$${NOFORMAT} ${DARKGRAY}${SCRIPT_NAME}${NOFORMAT}"

	echo -e ""
	echo -e " Lightweight utility for managing SSH keys for multiple GitHub repositories"
	echo -e " on a single machine. It's essentially a simplified version of the workflow"
	echo -e " described here: $(print_link "https://docs.github.com/developers/overview/managing-deploy-keys")"
	echo -e ""
	echo -e "${BOLD}Usage:${NOFORMAT}"
	echo -e "  $script_name $(print_cmd init) $(print_param "<source>")"
	echo -e "    Generate a new folder with a pair of labeled SSH keys under $(print_path $SSH_CI_DIR/)"
	echo -e "    The parameter $(print_param "source") must match one of the following formats:"
	echo -e "    $LIGHTGRAY - user/repo"
	echo -e "    $LIGHTGRAY - github.com/user/repo"
	echo -e "    $LIGHTGRAY - git@github.com:user/repo.git"
	echo -e ""
	echo -e "  $script_name $(print_cmd ls)"
	echo -e "    List all managed repositories"
	echo -e ""
	echo -e "  $script_name $(print_cmd rm) $(print_param "<repository>")"
	echo -e "    Permanently remove the SSH keys accociated with the repository"
	echo -e ""
	echo -e "  $script_name $(print_cmd dir) $(print_param "<repository>")"
	echo -e "    Print the full path to the folder containing the repository SSH keys"
	echo -e ""
	echo -e "  $script_name $(print_cmd origin) $(print_param "<repository>")"
	echo -e "    Print the origin for pulling/cloning the repository"
	echo -e ""
	echo -e "  $script_name $(print_cmd enable) $(print_param "<repository>")"
	echo -e "    Add a new entry for the repository in $(print_path $SSH_CONFIG_PATH)"
	echo -e ""
	echo -e "  $script_name $(print_cmd disable) $(print_param "<repository>")"
	echo -e "    Remove the repository entry in $(print_path $SSH_CONFIG_PATH)"
	echo -e ""
	echo -e "  $script_name $(print_cmd test) $(print_param "<repository>")"
	echo -e "    Check if the Deploy Key is set up correctly"
	echo -e ""
}

print_deploy_key_instructions() {
	local project_name="$1"
	local project_username=$(get_project_username "$project_name")
	local project_repository=$(get_project_repository "$project_name")
	local public_key_path=$(get_project_public_key_path "$project_name")

	echo -e ""
	echo -e " ${BOLD}🔑 GitHub Deploy Key${NOFORMAT}"
	echo -e " To finalize the setup, you need to create a new GitHub Deploy Key for your"
	echo -e " repository, which can be done here: $(print_link "https://github.com/${project_username}/${project_repository}/settings/keys${NOFORMAT}")."
	echo -e " Click on \"Add deploy key\" and enter the following properties: "
	echo -e ""
	echo -e "   ${BOLD}Title${NOFORMAT}"
	echo -e "   ${DIM}(Doesn't really matter, it can be anything you want)${NOFORMAT}"
	echo -e ""
	echo -e "   ${BOLD}Key${NOFORMAT}"
	echo -e "   ${LIGHTGRAY}$(cat "$public_key_path")${NOFORMAT}"
	echo -e ""
	echo -e ""
	echo -e " When you've saved the Deploy Key, you can run the"
	echo -e " following command to make sure everything works:"
	echo -e ""
	echo -e "             $DIM\$${NOFORMAT} $LIGHTGRAY$SCRIPT_NAME test $project_name $NOFORMAT"
}

add_project_to_config() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	local project_username=$(get_project_username "$project_name")
	local project_repository=$(get_project_repository "$project_name")
	local private_key_path=$(get_project_private_key_path "$project_name")

	if [ -z "$private_key_path" ]; then
		fatal "Could not find private key for project $project_name"
		exit 1
	fi

	touch "$SSH_CONFIG_PATH"

	if grep -q "IdentityFile=$private_key_path" $SSH_CONFIG_PATH; then
		success "Repository is already present in $SSH_CONFIG_PATH"
		print_deploy_key_instructions $project_name
		exit 0
	fi

	local project_ssh_hostname=$(get_project_ssh_hostname "$project_name")

	printf "\n" >> $SSH_CONFIG_PATH
	printf "%s\n" "# GitHub deploy key" >> $SSH_CONFIG_PATH
	printf "%s\n" "# Created: $(date)" >> $SSH_CONFIG_PATH
	printf "%s\n" "Host ${project_ssh_hostname} github.com" >> $SSH_CONFIG_PATH
	printf "\t%s\n" "HostName github.com" >> $SSH_CONFIG_PATH
	printf "\t%s\n" "IdentityFile=$private_key_path" >> $SSH_CONFIG_PATH

	success "Successfully added $project_name to $SSH_CONFIG_PATH"
	print_deploy_key_instructions $project_name
}

remove_project_from_config() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	local private_key_path=$(get_project_private_key_path "$project_name")
	local private_key_content=$(get_project_private_key "$project_name")

	if [ -z "$private_key_content" ]; then
		fatal "Could not find private key for project $project_name"
		exit 1
	fi

	local quoted_private_key_path=$(echo "$private_key_path" | sed 's/[][()\.\/^$?*+]/\\&/g')
  local updated=$(perl -0pe 's/((#.*\n)*.+\n([\t ]+.*\n)*[\t ]+IdentityFile='"$quoted_private_key_path"'\n([\t ]+.*\n)*)//gi' "$SSH_CONFIG_PATH")

	echo "$updated" > $SSH_CONFIG_PATH
}

create_project() {
	local url="$1"
	local regex='(.*github.com[/:]){0,1}(.*)/(.*)(.git{0,1}|\/|$)'

	# ssh -T "git@$project_name"
	if [[ $url =~ $regex ]]; then
		local username=$(echo "${BASH_REMATCH[2]}" | awk '{print tolower($0)}')
		local repository=$(echo "${BASH_REMATCH[3]}" | awk '{print tolower($0)}')

		if [[ -z $username || -z $repository ]]; then
			fatal "Invalid GitHub URL!"
			exit 1
		fi

		# Create an absolut path to our directory
		local directory="$SSH_CI_DIR/$username/$repository"

		# Make sure the directory exists
		mkdir -p "$directory"

		# Abort if the directory isn't empty
		if [ "$(ls -A $directory)" ]; then
			fatal "Repository already exists!"
			exit 1
		fi

		# Path to our private key
		local path="$directory/$SSH_KEY_FILENAME"

		ssh-keygen -t ed25519 -C "github.com/$username/$repository" -f "$path" -P ""
		eval "$(ssh-agent -s)"
		ssh-add "$path"

		success "Successfully generated SSH keys for repository $username/$repository!"
	else
		fatal "Invalid GitHub URL!"
		exit 1
	fi
}

remove_project() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	local project_path=$(get_project_path "$project_name")
	local project_ssh_hostname=$(get_project_ssh_hostname "$project_name")

	printf "Are you sure you want to remove ${CYAN}${UNDERLINE}${project_path}${NOFORMAT}? "
	read -p "(y/N) " -r

	if [[ $REPLY =~ ^[Yy]$ ]]; then
		remove_project_from_config "$project_name"
		ssh-keygen -R "${project_ssh_hostname}.github.com" 2>/dev/null

		rm -rf "$project_path"
	else
		exit 1;
	fi
}

test_project() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	# Make sure the project has an entry in SSH config
	if ! grep -Fq "IdentityFile=${private_key_path}" $SSH_CONFIG_PATH; then
		fatal "Could not find an entry for project $1 in $SSH_CONFIG_PATH!"
		exit 1
	fi

	local project_ssh_hostname=$(get_project_ssh_hostname "$project_name")

	# Try to connect to the remote using SSH
	local ssh_exit_code=$(ssh -n "git@$project_ssh_hostname" >/dev/null 2>&1; echo $?)

	if [ $ssh_exit_code -eq 255 ]; then
		fatal "Unable to connect to remote:${NOFORMAT} git@${project_name}"
		fatal "Have you added the public key to the GitHub repository?"
		exit 1
	fi

	success "Success!"
}

print_project_path() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	local project_path=$(get_project_path "$project_name")

	echo "$project_path"
}

print_project_origin() {
	local project_name="$1"

	# Make sure the project exists
	if ! does_project_exist $project_name; then
		fatal "Project $project_name does not exist"
		exit 1
	fi

	local project_path=$(get_project_path "$project_name")
	local project_ssh_hostname=$(get_project_ssh_hostname "$project_name")
	local username=$(get_project_username "$project_name")
	local repository=$(get_project_repository "$project_name")

	echo "git@${project_ssh_hostname}:${username}/${repository}.git"
}

parse_input() {
	if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
		print_usage
		exit 0
	fi

	if [ "$1" = "ls" ]; then
		list_projects
		exit 0
	fi

	if [[ ! -z $1 ]] && [[ -z $2 ]]; then
		fatal "No repository specified!"
		exit 1
	fi

	if [ "$1" = "init" ]; then
		create_project "$2"
		exit 0
	fi

	if [ "$1" = "rm" ]; then
		remove_project "$2"
		exit 0
	fi

	if [ "$1" = "dir" ]; then
		print_project_path "$2"
		exit 0
	fi

	if [ "$1" = "origin" ]; then
		print_project_origin "$2"
		exit 0
	fi

	if [ "$1" = "enable" ]; then
		add_project_to_config "$2"
		exit 0
	fi

	if [ "$1" = "disable" ]; then
		remove_project_from_config "$2"
		exit 0
	fi

	if [ "$1" = "test" ]; then
		test_project "$2"
		exit 0
	fi

	print_usage
}

setup_colors
parse_input $@