backup-docker-psql

#!/bin/bash

# Script to backup postgresql containers
# When no args are specified, it will try to guess the settings

_RED='\033[0;31m'
_ORANGE='\033[0;33m'
_BOLD_BLUE='\033[1;34m'
_NC='\033[0m'

_show_usage() {
  echo "$0 --container [container] --name [db_name] --user [db_user]"
}

_show_error() {
  echo -e "${_RED}${1}${_NC}" 1>&2
}

_show_title() {
  echo -e "${_BOLD_BLUE}${1}${_NC}" 1>&2
}

_debug() {
  # shellcheck disable=SC2154
  if [[ "${DEBUG}" -eq 1 ]]; then
    echo -e "${_ORANGE}${1}${_NC}" 1>&2
  fi
}

_backup() {
  if [[ -z "${_DB_NAME}" ]]; then
    _debug "No database specified, fetching local config file"
    # shellcheck disable=SC1091
    if source .env 2>/dev/null; then
      # shellcheck disable=SC2154
      _debug "from env file: ${POSTGRES_DB}"
      # shellcheck disable=SC2154
      _debug "from env file: ${POSTGRES_USER}"
    fi
    if [[ -z "${POSTGRES_DB}" || -z "${POSTGRES_USER}" ]]; then
      _show_error "Cannot guess DB name or user"
      _show_usage
      exit 2
    fi

    _DB_NAME=${POSTGRES_DB}
    _DB_USER=${POSTGRES_USER}
  fi

  if [[ -z ${_CONTAINER} ]]; then

    _debug "No container specified, guessing container name"
    if (command -v jq && command -v yq) &>/dev/null; then
      _CONTAINER=$(yq ".services[].container_name" <docker-compose.yml | grep "postgres" | tr -d \")
    fi

    if [[ -z "${_CONTAINER}" ]]; then
      _CONTAINER=$(docker ps --format "{{.Names}}" | grep "postgres")
    fi

    if [[ -z "${_CONTAINER}" ]]; then
      _show_error "Cannot find a matching container"
      _show_usage
      exit 1
    fi
    if [[ "${_CONTAINER}" == *$'\n'* ]]; then
      _show_error "Found multiple Postgres containers:"
      _show_error "${_CONTAINER}"
      _show_error "Please choose one"
      exit 1
    fi
  fi

  _BACKUP_NAME="${_CONTAINER}-$(date +'%Y%m%d').backup"

  _show_title "Postgres database backup"
  echo -e "Container:\t${_CONTAINER}"
  echo -e "Database name:\t${_DB_NAME}"
  echo -e "Databaser user:\t${_DB_USER}"
  echo -e "Backup name:\t${_BACKUP_NAME}"

  if [[ "${_CONFIRM}" != 1 ]]; then
    echo -n "Is this ok?? [y/N]: "
    read -r continue
    if [[ ${continue} != "y" ]]; then
      echo "Opertion aborted" && exit 3
    fi
  fi

  echo
  docker exec "${_CONTAINER}" pg_dump -U "${_DB_USER}" -Fc "${_DB_NAME}" >"${_BACKUP_NAME}"
}

while [[ $# -gt 0 ]]; do
  key="$1"
  case ${key} in
  -n | --name)
    _DB_NAME="$2"
    shift
    ;;
  -u | --user)
    _DB_USER="$2"
    shift
    ;;
  -c | --container)
    _CONTAINER="$2"
    shift
    ;;
  -y)
    _CONFIRM=1
    ;;
  -h | --help | help)
    _show_usage && exit 0
    ;;
  *)
    # unknown option
    _show_usage && exit 0
    ;;
  esac
  shift # past argument or value
done

_backup