Drupal/Drush - Dump database from alias to file

ac-dump.sh

#!/usr/bin/env bash

##
# Print usage instructions
##
usage() {
  echo "Usage:"
  echo "  ac-dump.sh @alias"
  echo "    It will copy the database from the alias to a local file named as the alias in gzip format"
  echo ""
  echo "  ac-dump.sh -h"
  echo "    Display this message."
  echo ""
}

##
# If database backup failed. We can add more work here
##
failed_db_dump() {
  echo "There was an issue with the dump."

  # try to delete file
  rm "$1"
  if [[ $? -eq 0 ]]; then
    echo "File $1 has been deleted."
  else
    echo "Couldn't delete file - $1"
  fi

  exit 1;
}

##
# If database export worked, print message
##
success_db_dump() {
  echo "Database exported to $1"
}

##
# Export database and check if valid file
##
dump_db() {
  #generate name
  local file_name
  file_name="$1-$(date '+%F_%H.%M.%S').sql.gz"

  # remove first character, "@"
  # man bash, search for "parameter:offset:length"
  file_name=${file_name:1}

  #dump database to file
  drush "$1" sql-dump --gzip > "$file_name"

  # Check if file is a gzipped file.
  type=$(file "$file_name")
  if [[ "$type" != *" gzip compressed data,"* ]]; then
    failed_db_dump "$file_name"
  else
    success_db_dump "$file_name"
  fi
}

#####################
# Main logic starts here
#####################

## If there are no arguments, show usage and exit.
if [[ $# -eq 0 ]]; then
  echo "No arguments supplied"
  usage
  exit 1
fi

##
# If there's more than 1 argument
# @TODO: should we add support to check and iterate over all?
#   Something to consider for the future...
##
if [[ $# -gt 1 ]]; then
  echo "Too many arguments supplied"
  usage
  exit 1
fi

##
# If there are arguments and they're exactly 1
##
case $1 in
 -h) usage; exit;;
 --help) usage; exit;;
 -*) echo "Invalid arguments"; usage; exit 1;;
 @*) dump_db $1;;
 *) dump_db "@$1";;
esac