git-ssh-install-hooks

#!/bin/sh

readonly BASENAME="git-ssh"
readonly NAME="${BASENAME}-install-hooks"
readonly VERSION="0.0.1"

readonly HOOK_SOURCE="${HOOK_SOURCE:-/usr/share/${BASENAME}/hooks}"
readonly GIT_DIR="${GIT_DIR:-.git}"

_log() {
  _msg="$1"
  shift

  printf -- "[%s] ${_msg}\n" "${NAME}" "$@"

  unset _msg
  return 0
}

##
# Error Log
#
# Accepts arguments in the same format as printf
# $1 message
# $@ arguments
##
_elog() {
  _log "$@" 1>&2 || return 1
  return 0
}

_collect_hooks() {
  _hooks=""
  for _h in "${HOOK_SOURCE}"/*; do
    if [ -r "${_h}" ]; then
      if [ -z "${_hooks}" ]; then
        _hooks="${_h}"
      else
        _hooks="${_hooks}
${_h}"
      fi
    fi
    unset _h
  done
  unset _h

  printf -- '%s\n' "${_hooks}"

  unset _hooks
  return 0
}

_inform_hooks() {
  printf -- 'The following files will be installed:\n'
  _collect_hooks || return 1
  return 0
}

_usage() {
  printf -- '%s\n' "$(
    cat <<EOF
${NAME} [${VERSION}] <command>

This script will install/overwrite your git repository prepare-commit-msg hooks
to check and enforce that all committers have a signed SSH key present.

[Commands]
install [--force]    Install hooks (--force will overwrite existing hooks)
list                 List hooks

[Hooks]
$(_inform_hooks)
EOF
  )"
}

_do_install() {
  _install_target="$1"

  _log 'Installing %s -> %s' "${_install_target}" "${GIT_DIR}/hooks"

  cp -f "${_install_target}" "${GIT_DIR}/hooks" || {
    _elog 'Failed to install %s' "${_install_target}"

    unset _install_target
    return 1
  }

  unset _install_target
  return 0
}

_is_git_project() {
  [ -d "${GIT_DIR}" ] && [ -d "${GIT_DIR}/hooks" ]
}

_install() {
  _forced="$1"

  for _hook in $(_collect_hooks); do
    case "${_hook}" in
    *.prepare-commit-msg)
      _do_install "${_hook}" || {
        _elog 'Failed to install hook %s' "$(basename "${_hook}")"
        unset _hook
        unset _forced
        return 1
      }
      ;;
    *)
      if [ "${_forced}" -eq 0 ]; then
        # If the file already exists, prompt user
        if [ -r "${GIT_DIR}/hooks/$(basename "${_hook}")" ]; then
          # Don't use _log so we don't force a newline
          printf -- '[%s] Are you sure you want to overwrite the existing hook %s? (y/N) ' "${NAME}" "$(basename "${_hook}")"

          IFS= read -r _yes
          case "${_yes}" in
          y | Y | yes | YES)
            _do_install "${_hook}" || {
              _elog 'Failed to install hook %s' "$(basename "${_hook}")"
              unset _hook
              unset _forced
              return 1
            }
            ;;
          *)
            _log 'Skipping install of hook %s' "$(basename "${_hook}")"
            continue
            ;;
          esac
        else
          _do_install "${_hook}" || {
            _elog 'Failed to install hook %s' "$(basename "${_hook}")"
            unset _hook
            unset _forced
            return 1
          }
        fi
      else
        _do_install "${_hook}" || {
          _elog 'Failed to install hook %s' "$(basename "${_hook}")"
          unset _hook
          unset _forced
          return 1
        }
      fi
      ;;
    esac
    unset _hook
  done
  unset _hook

  unset _forced
  return 0
}

_list() {
  _inform_hooks || return 1
  return 0
}

main() {
  _cmd=""
  _force_install=0

  while [ -n "$1" ]; do
    case "$1" in
    install)
      _cmd="install"
      ;;
    list)
      _cmd="list"
      ;;
    --force)
      _force_install=1
      ;;
    esac

    shift
  done

  case "${_cmd}" in
  install)
    if ! _is_git_project; then
      _elog 'Cannot install hook. This is not a git project?'
      return 1
    fi

    _install "${_force_install}" || return 1
    ;;
  list)
    _list || return 1
    ;;
  *)
    _usage || return 1
    return 1
    ;;
  esac

  return 0
}

main "$@" || exit 1
exit 0