Utility for backing up a remote Andromeda Postgres DB. Preserves only the past X database dumps.

backup-andromeda-db.sh

#!/usr/bin/env bash

##
# @author J. Elliot Taylor (@jaytaylor)
#
# @date 2018-11-14
#
# @description Andromeda postgres DB remote backup utility.
#

set -o errexit
set -o pipefail
set -o nounset

#set -x

export SSH_HOST='web'
export DB_NAME='andromeda'
export LOCAL_PATH='/datastore/backups/andromeda/db'
export PRESERVE_NUM_BACKUPS=14

function backupDB() {
    mkdir -p "${LOCAL_PATH}"

    # shellcheck disable=SC2029
    ssh -C "${SSH_HOST}" pg_dump "${DB_NAME}" \
        | gzip > "${LOCAL_PATH}/${DB_NAME}.$(date +%Y%m%d%H%M%S).sql.gz"
}

function cleanupOld() {
    local expired
    local ifsBak

    mkdir -p "${LOCAL_PATH}"
    cd "${LOCAL_PATH}"

    # Preserve only the newest X files.  Do it in a way which is safe for files
    # containing spaces in the name.
    #
    # `find' is used than `ls' to better handle non-alphanumeric filenames.
    #
    # Thanks to https://stackoverflow.com/a/16962596/293064 for the
    # `cut --complement' trick.
    expired="$(find "${LOCAL_PATH}" -mindepth 1 -maxdepth 1 -printf "%T+ %p\n" | sort --reverse | cut -d ' ' -f 2- | awk "NR>${PRESERVE_NUM_BACKUPS}")"
    if [ -n "${expired}" ] ; then
        ifsBak="${IFS:-}"
        IFS=$'\n'

        # shellcheck disable=SC2001
        echo -e "INFO: Removing $(echo "${expired}" | wc -l) file(s):\n$(echo "${expired}" | sed 's/^/    /')" 1>&2
        for f in ${expired} ; do
            rm -rf "${f}"
        done

        export IFS="${ifsBak}"
    fi

    cd -
}

if [ "${BASH_SOURCE[0]}" = "${0}" ] ; then
    # Only auto-run when being executed (and don't auto-run functions when being
    # sourced).
    backupDB
    cleanupOld
fi