backup-docker-volumes

#!/usr/bin/env bash

set -e

# Script version
readonly VERSION=0.0.1
# Script filename
readonly FILENAME=$(basename ${0})
# Current date
readonly DATE=$(date "+%Y-%m-%d")
# https://github.com/theobori/dockerv
#
# dockerv source points
#
# You can replace $@ by the sources point you want
# instead of passing CLI arguments
readonly SOURCE_POINTS=( $@ )
# Retention days amount
readonly RETENTION=${RETENTION:-3}
# Backup directory path
readonly BACKUP_DIR=${BACKUP_DIR:-"/backup"}
# dockerv destination point
readonly DESTINATION_POINT="${BACKUP_DIR}/docker-volumes-${DATE}.tar.gz"

# Help display function
print_help() {
    cat <<USAGE
${FILENAME}
Version ${VERSION}

Optional arguments
  -h        Show this help message
  -v        Print the script version

Usage example
${FILENAME} src1 src2 src3
USAGE
}

# Parsing the CLI arguments with the built-in getopts command
parse() {
    while getopts "hv" arg; do
        case ${arg} in
            h)
                print_help
                exit 0
                ;;

            v)
                echo ${FILENAME} -- ${VERSION}
                exit 0
                ;;
        esac
    done

    if [[ ${#SOURCE_POINTS[@]} -eq 0 ]]
    then
        echo "Missing sources, check the help message" >&2
        return 1
    fi
}

# Exporting and packing Docker volumes
# selected with the source points as a Tarball
export_docker_volumes() {
    local args=""

    for source_point in ${SOURCE_POINTS[@]}
    do
        args+="--src \"${source_point}\" "
    done

    if ! dockerv export \
        ${args} \
        --dest ${DESTINATION_POINT} \
        --force
    then
        return 1
    fi
}

# Deleting files older than ${RETENTION} days
purge_backups() {
    find ${BACKUP_DIR} \
        -type f \
        -mtime +${RETENTION} \
        -delete
    
    echo "Deleted files older than ${RETENTION} days in ${BACKUP_DIR}"
}

main() {
    parse ${@} || exit 1

    mkdir -p ${BACKUP_DIR}

    echo "Starting Docker volumes export"

    export_docker_volumes || exit 1
    purge_backups
}

main ${@}