Dumping database script

dump.sh

#!/usr/bin/env bash

DAYS_TO_KEEP=6
DB_USER=postgres
DUMP_DIR=/var/db_dumps

function create_dump_dir_unless_exist() {
  if ! mkdir -p $DUMP_DIR
  then
    echo "Cannot create backup directory in $DUMP_DIR" 1>&2
    exit 1
  fi
}

function dump_postgres_config() {
  local postgres_config_file="${DUMP_DIR}/postgres.dump"
  pg_dumpall --globals-only > $postgres_config_file
}

function dump_database_if_exists() {
  if database_exists $1; then
    dump $1
  else
    echo "Database '$1' does not exist!"
  fi
}

function database_exists() {
  psql -lqt | cut -d \| -f 1 | grep -wq $1
}

function dump() {
  local filename=$(filename $1)

  if ! pg_dump -U $DB_USER $1 | gzip > $filename.in_progress; then
    echo "Failed to backup $1" 1>&2
    exit 1
  else
    mv $filename.in_progress $filename
  fi
}

function filename() {
  local timestamp=$(date +\%d-\%B-\%Y)
  local dbname=$1
  echo "${DUMP_DIR}/${dbname}_${timestamp}.sql.gz"
}

function remove_old_dumps() {
  find $DUMP_DIR -maxdepth 1 -mtime +$DAYS_TO_KEEP -name $1"_*" -exec rm -rf '{}' ';'
}

function validate_arguments() {
  if [[ $# -ne 1 ]]; then
    echo "Please provide exactly one argument with adatabase name to dump!"
    exit 1
  fi
}

function main() {
  validate_arguments $@
  create_dump_dir_unless_exist
  dump_postgres_config
  dump_database_if_exists $1
  remove_old_dumps $1
}

main $@