#!/bin/bash

# Exit script if command fails
# -u stops the script on unset variables
# -e stops the script on errors
# -o pipefail stops the script if a pipe fails
set -eo pipefail

# Display Help
Help() {
    echo
    echo "docker-mysql-backup"
    echo "###################"
    echo
    echo "Description: Backup docker mysql database."
    echo "Syntax: docker-mysql-backup [-d|-o|-c|help]"
    echo "Example: docker-mysql-backup -d mysql,odoo -o /tmp -c mysql01"
    echo "options:"
    echo "  -d    Comma-separated list of database names."
    echo "  -a    Backup all databases"
    echo "  -o    Output directory. Defaults to '/var/tmp'"
    echo "  -c    Docker container name. Defaults to 'mysql'"
    echo "  help  Show docker-mysql-backup manual."
    echo
}

# Show help and exit
if [[ $1 == 'help' ]]; then
    Help
    exit
fi

# Process params
while getopts ":a :c: :d: :o:" opt; do
  case $opt in
    a) ALL='true'
    ;;
    c) CONTAINER="$OPTARG"
    ;;
    d) DATABASES="$OPTARG"
    ;;
    o) DIR="$OPTARG"
    ;;
    \?) echo "Invalid option -$OPTARG" >&2
    Help
    exit;;
  esac
done

# Fallback to environment vars and default values
: ${DIR:='/var/tmp'}
: ${CONTAINER:='mysql'}

# Verify variables
[[ -z "$DATABASES" ]] && [[ -z "$ALL" ]] && { echo "Parameter -d or -a|databases or all must be set" ; exit 1; }
[[ -z "$DIR" ]] && { echo "Parameter -d|dir is empty" ; exit 1; }
[[ -z "$CONTAINER" ]] && { echo "Parameter -c|container is empty" ; exit 1; }

if $ALL ; then
  # Get all databases from docker container
  DATABASE_LIST=($(docker exec $CONTAINER /bin/bash -c "mysql -p\$MYSQL_ROOT_PASSWORD \
    -Bse 'SHOW DATABASES' | grep -v -E '^(sys|information_schema|mysql|performance_schema)$'"))
  # Concate database list
  printf -v DATABASES '%s,' "${DATABASE_LIST[@]}"
  DATABASES="${DATABASES%,}"
fi

if [[ ! -z $DATABASES ]] ; then
  # Split database param values
  DATABASE_LIST=($(echo $DATABASES | tr "," "\n"))
fi

# Create backup folder
mkdir -p ${DIR}/${CONTAINER}

# Cleanup backup folder
rm -rf ${DIR}/${CONTAINER}/*

# Create dump with docker for each database
for DATABASE in "${DATABASE_LIST[@]}"
do
    echo "Run Docker mysql backup for $DATABASE"
    docker exec $CONTAINER /bin/bash -c "mysqldump -p\$MYSQL_ROOT_PASSWORD \
        $DATABASE" > ${DIR}/${CONTAINER}/${DATABASE}.sql
done

# Notify if backup has finished
echo "The Docker mysql backup has finished: ${DIR}/${CONTAINER}/{${DATABASES}}.sql"
