#!/bin/bash

# {{{ License and Copyright
# PostgreSQL Backup Script
# https://github.com/k0lter/autopostgresqlbackup
# Copyright (c) 2005 Aaron Axelsen <axelseaa@amadmax.com>
#               2005 Friedrich Lobenstock <fl@fl.priv.at>
#               2013-2023 Emmanuel Bouthenot <kolter@openics.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# }}}

# {{{ Variables
# Username to access the PostgreSQL server e.g. dbuser
USERNAME=postgres

# Password
# create a file ${HOME}/.pgpass containing a line like this
#   hostname:*:*:dbuser:dbpass
# replace hostname with the value of DBHOST and postgres with
# the value of USERNAME

# Host name (or IP address) of PostgreSQL server e.g localhost
DBHOST=localhost

# Port of PostgreSQL server e.g 5432 (only used if DBHOST != localhost)
DBPORT=5432

# List of DBNAMES for Daily/Weekly Backup e.g. "DB1 DB2 DB3"
DBNAMES="all"

# pseudo database name used to dump global objects (users, roles, tablespaces)
GLOBALS_OBJECTS="postgres_globals"

# Backup directory location e.g /backups
BACKUPDIR="/var/backups"

# Email Address to send mail to? (user@domain.com)
MAILADDR="user@domain.com"

# ============================================================
# === ADVANCED OPTIONS ( Read the doc's below for details )===
#=============================================================

# List of DBNAMES to EXLUCDE if DBNAMES are set to all (must be in " quotes)
DBEXCLUDE=""

# Include CREATE DATABASE in backup?
CREATE_DATABASE=yes

# Which day do you want weekly backups? (1 to 7 where 1 is Monday)
# When set to 0, weekly backups are disabled
DOWEEKLY=6

# Which day do you want monthly backups? (default is 1, first day of the month)
# When set to 0, monthly backups are disabled
DOMONTHLY=1

# Backup retention count for daily backups
# Default is 14 days
BRDAILY=14

# Backup retention count for weekly backups
# Default is 5 weeks
BRWEEKLY=5

# Backup retention count for monthly backups
# Default is 12 months
BRMONTHLY=12

# Choose Compression type. (gzip, pigz, bzip2, xz or zstd)
COMP=gzip

# Compression options
COMP_OPTS=

# OPT string for use with pg_dump (see man pg_dump)
OPT=""

# Backup files extension
EXT="sql"

# Backup files permission
PERM=600

# Encryption settings
# (inspired by http://blog.altudov.com/2010/09/27/using-openssl-for-asymmetric-encryption-of-backups/)
#
# It is recommended to backup into a staging directory, and then use the
# POSTBACKUP script to sync the encrypted files to the desired location.
#
# Encryption uses private/public keys. You can generate the key pairs like the following:
# openssl req -x509 -nodes -days 100000 -newkey rsa:2048 -keyout backup.key -out backup.crt -subj '/'
#
# Decryption:
# openssl smime -decrypt -in backup.sql.gz.enc -binary -inform DEM -inkey backup.key -out backup.sql.gz

# Enable encryption
ENCRYPTION=no

# Encryption public key (path to the key)
ENCRYPTION_PUBLIC_KEY=""

# Encryption Cipher (see enc manpage)
ENCRYPTION_CIPHER="aes256"

# Suffix for encyrpted files
ENCRYPTION_SUFFIX=".enc"

# Command to run before backups (uncomment to use)
#PREBACKUP="/etc/postgresql-backup-pre"

# Command run after backups (uncomment to use)
#POSTBACKUP="/etc/postgresql-backup-post"
# }}}

# {{{ OS Specific
if [ -f /etc/default/autopostgresqlbackup ]; then
    # shellcheck source=/dev/null
    . /etc/default/autopostgresqlbackup
fi
# }}}

# {{{ Documentation
#=====================================================================
# Options documentation
#=====================================================================
# Set USERNAME and PASSWORD of a user that has at least SELECT permission to
# ALL databases.
#
# Set the DBHOST option to the server you wish to backup, leave the default to
# backup "this server". To backup multiple servers make copies of this file and
# set the options for that server.
#
# Put in the list of DBNAMES (Databases) to be backed up. If you would like to
# backup ALL DBs on the server set DBNAMES="all". If set to "all" then any new
# DBs will automatically be backed up without needing to modify this backup
# script when a new DB is created.
#
# If the DB you want to backup has a space in the name replace the space with a
# % e.g. "data base" will become "data%base"
#
# You can change the backup storage location to anything you like by using the
# BACKUPDIR setting.
#
# === Advanced options doc's ===
#
# If you set DBNAMES="all" you can configure the option DBEXCLUDE. Other wise
# this option will not be used. This option can be used if you want to backup
# all dbs, but you want exclude some of them. (eg. if a db is to big).
#
# Set CREATE_DATABASE to "yes" (the default) if you want your SQL-Dump to
# create a database with the same name as the original database when restoring.
# Saying "no" here will allow your to specify the database name you want to
# restore your dump into, making a copy of the database by using the dump
# created with autopostgresqlbackup.
#
# Use PREBACKUP and POSTBACKUP to specify Per and Post backup commands
# or scripts to perform tasks either before or after the backup process.
#
#=====================================================================
# Backup Rotation..
#=====================================================================
#
# Rotation is configurable for each period:
#  - daily (max $BRDAILY backups are keeped)
#  - weekly (max $BRWEEKLY backups are keeped)
#  - monthy (max $BRMONTHLY backups are keeped)
#
# }}}

# {{{ Defaults
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/postgres/bin:/usr/local/pgsql/bin
HOMEPAGE="https://github.com/k0lter/autopostgresqlbackup"
NAME="AutoPostgreSQLBackup"         # Script name
VERSION="2.0"                       # Version Number
DATE="$(date '+%Y-%m-%d_%Hh%Mm')"   # Datestamp e.g 2002-09-21
DNOW="$(date '+%u')"                # Day number of the week 1 to 7 where 1 represents Monday
DNOM="$(date '+%d')"                # Date of the Month e.g. 27
LOG_DIR="${BACKUPDIR}"              # Directory where the main log is saved
# Fix day of month (left padding with 0)
DOMONTHLY="$(echo "${DOMONTHLY}" | sed -r 's/^[0-9]$/0\0/')"

# Using a shared memory filesystem (if available) to avoid
# issues when there is no left space on backup storage
if [ -w "/dev/shm" ]; then
    LOG_DIR="/dev/shm"
fi

LOG_FILE="${LOG_DIR}/${NAME}_${DBHOST//\//_}-$(date '+%Y-%m-%d_%Hh%Mm').log"

# Debug mode
DEBUG="no"

# pg_dump options
if [ -n "${OPT}" ]; then
    IFS=" " read -r -a PG_OPTIONS <<< "${OPT}"
else
    PG_OPTIONS=()
fi

# Create required directories
if [ ! -e "${BACKUPDIR}" ]; then         # Check Backup Directory exists.
    mkdir -p "${BACKUPDIR}"
fi

if [ ! -e "${BACKUPDIR}/daily" ]; then   # Check Daily Directory exists.
    mkdir -p "${BACKUPDIR}/daily"
fi

if [ ! -e "${BACKUPDIR}/weekly" ]; then  # Check Weekly Directory exists.
    mkdir -p "${BACKUPDIR}/weekly"
fi

if [ ! -e "${BACKUPDIR}/monthly" ]; then # Check Monthly Directory exists.
    mkdir -p "${BACKUPDIR}/monthly"
fi

# Hostname for LOG information and
# pg_dump{,all} connection settings
if [ "${DBHOST}" = "localhost" ]; then
    HOST="$(hostname --fqdn)"
    PG_CONN=()
else
    HOST="${DBHOST}:${DBPORT}"
    PG_CONN=(--host "${DBHOST}" --port "${DBPORT}")
fi
if [ -n "${USERNAME}" ]; then
    PG_CONN+=(--username "${USERNAME}")
fi
# }}}

# {{{ log{,ger,_info,_debug,_warn,_error}()
logger() {
    local fd line severity reset color

    fd="${1}"
    severity="${2}"
    reset=
    color=

    if [ -n "${TERM}" ]; then
        reset="\e[0m"
        case "${severity}" in
            error)
                color="\e[0;91m"
                ;;
            warn)
                color="\e[0;93m"
                ;;
            debug)
                color="\e[0;96m"
                ;;
            *)
                color="\e[0;94m"
                ;;
        esac
    fi

    while IFS= read -r line ; do
        printf "%s|%s|%s\n" "${fd}" "${severity}" "${line}" >> "${LOG_FILE}"
        if [ "${DEBUG}" = "yes" ]; then
            if [ "${fd}" = "out" ]; then
                printf "${color}%6s${reset}|%s\n" "${severity}" "${line}" >&6
            elif [ "${fd}" = "err" ]; then
                printf "${color}%6s${reset}|%s\n" "${severity}" "${line}" >&7
            fi
        fi
    done
}

log() {
    echo "$@" | logger "out" ""
}

log_debug() {
    echo "$@" | logger "out" "debug"
}

log_info() {
    echo "$@" | logger "out" "info"
}

log_error() {
    echo "$@" | logger "err" "error"
}

log_warn() {
    echo "$@" | logger "err" "warn"
}
# }}}

# {{{ dblist()
dblist () {
    local cmd_prog cmd_args raw_dblist dblist dbexcl databases

    cmd_prog="psql"
    cmd_args=(-t -l -A -F:)

    if [ "${#PG_CONN[@]}" -gt 0 ]; then
        cmd_args+=("${PG_CONN[@]}")
    fi

    log_debug "Running command: ${cmd_prog} ${cmd_args[*]}"
    raw_dblist=$(
        if [ -n "${SU_USERNAME}" ]; then
            su - "${SU_USERNAME}" -l -c "${cmd_prog} ${cmd_args[*]}"
        else
            "${cmd_prog}" "${cmd_args[@]}"
        fi
    )

    read -r -a dblist <<< "$(
        printf "%s" "${raw_dblist}" | \
            sed -r -n 's/^([^:]+):.+$/\1/p' | \
            tr '\n' ' '
    )"
    log_debug "Automatically found databases: ${dblist[*]}"

    if [ -n "${DBEXCLUDE}" ]; then
        IFS=" " read -r -a dbexcl <<< "${DBEXCLUDE}"
    else
        dbexcl=()
    fi
    dbexcl+=(template0)
    log_debug "Excluded databases: ${dbexcl[*]}"

    mapfile -t databases < <(
        comm -23 \
            <(IFS=$'\n'; echo "${dblist[*]}" | sort) \
            <(IFS=$'\n'; echo "${dbexcl[*]}" | sort) \
        )
    databases+=("${GLOBALS_OBJECTS}")
    log_debug "Database(s) to be backuped: ${databases[*]}"

    printf "%s " "${databases[@]}"
}
# }}}

# {{{ dbdump()
dbdump () {
    local db cmd_prog cmd_args pg_args

    db="${1}"
    pg_args="${PG_OPTIONS[*]}"

    if [ "${db}" = "${GLOBALS_OBJECTS}" ]; then
        cmd_prog="pg_dumpall"
        cmd_args=(--globals-only)
    else
        cmd_prog="pg_dump"
        cmd_args=("${DB}")
        if [ "${CREATE_DATABASE}" = "yes" ]; then
            pg_args+=(--create)
        fi
    fi

    if [ "${#PG_CONN[@]}" -gt 0 ]; then
        cmd_args+=("${PG_CONN[@]}")
    fi
    if [ "${#pg_args[@]}" -gt 0 ]; then
        cmd_args+=("${pg_args[@]}")
    fi

    log_debug "Running command: ${cmd_prog} ${cmd_args[*]}"
    if [ -n "${SU_USERNAME}" ]; then
        su - "${SU_USERNAME}" -l -c "${cmd_prog} ${cmd_args[*]}"
    else
        "${cmd_prog}" "${cmd_args[@]}"
    fi
}
# }}}

# {{{ encryption()
encryption() {
    log_debug "Encrypting using cypher ${ENCRYPTION_CIPHER} and public key ${ENCRYPTION_PUBLIC_KEY}"
    openssl smime -encrypt -${ENCRYPTION_CIPHER} -binary -outform DEM "${ENCRYPTION_PUBLIC_KEY}" 2>&7
}
# }}}

# {{{ compression()
compression () {
    if [ -n "${COMP_OPTS}" ]; then
        IFS=" " read -r -a comp_args <<< "${COMP_OPTS}"
        log_debug "Compressing using '${COMP} ${comp_args[*]}'"
        "${COMP}" "${comp_args[@]}" 2>&7
    else
        log_debug "Compressing using '${COMP}'"
        "${COMP}" 2>&7
    fi
}
# }}}

# {{{ dump()
dump() {
    local db_name dump_file comp_ext

    db_name="${1}"
    dump_file="${2}"

    if [ -n "${COMP}" ]; then
        comp_ext=".comp"
        case "${COMP}" in
            gzip|pigz)
                comp_ext=".gz"
                ;;
            bzip2)
                comp_ext=".bz2"
                ;;
            xz)
                comp_ext=".xz"
                ;;
            zstd)
                comp_ext=".zstd"
                ;;
        esac
        dump_file="${dump_file}${comp_ext}"
    fi

    if [ "${ENCRYPTION}" = "yes" ]; then
        dump_file="${dump_file}${ENCRYPTION_SUFFIX}"
    fi

    if [ -n "${COMP}" ] && [ "${ENCRYPTION}" = "yes" ]; then
        log_debug "Dumping (${db_name}) +compress +encrypt to '${dump_file}'"
        dbdump "${db_name}" | compression | encryption > "${dump_file}"
    elif [ -n "${COMP}" ]; then
        log_debug "Dumping (${db_name}) +compress to '${dump_file}'"
        dbdump "${db_name}" | compression > "${dump_file}"
    elif [ "${ENCRYPTION}" = "yes" ]; then
        log_debug "Dumping (${db_name}) +encrypt to '${dump_file}'"
        dbdump "${db_name}" | encryption > "${dump_file}"
    else
        log_debug "Dumping (${db_name}) to '${dump_file}'"
        dbdump "${db_name}" > "${dump_file}"
    fi

    if [ -f "${dump_file}" ]; then
        log_debug "Fixing permissions (${PERM}) on '${dump_file}'"
        chmod "${PERM}" "${dump_file}"
        if [ ! -s "${dump_file}" ]; then
            log_error "Something went wrong '${dump_file}' is empty (no space left on device?)"
        fi
    else
        log_error "Something went wrong '${dump_file}' does not exists (error during dump?)"
    fi
}
# }}}

# {{{ cleanup()
cleanup() {
    local dumpdir db when count line

    dumpdir="${1}"
    db="${2}"
    when="${3}"
    count="${4}"

    # Since version >= 2.0 the dump filename no longer contains the week number
    # or the abbreviated month name so in order to be sure to remove the older
    # dumps we need to sort the filename on the datetime part (YYYY-MM-DD_HHhMMm)

    log_info "Rotating ${count} ${when} backups..."
    log_debug "Looking for '${db}_*' in '${dumpdir}/${when}/${db}'"
    find "${dumpdir}/${when}/${db}/" -name "${db}_*" | \
        sed -r 's/^.+([0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{2}h[0-9]{2}m).*$/\1 \0/' | \
        sort -r | \
        sed -r -n 's/\S+ //p' | \
        tail "+${count}" | \
        xargs -L1 rm -fv | \
        while IFS= read -r line ; do
            log_info "${line}"
        done
}
# }}}

# {{{ usage()
usage() {
cat <<EOH
USAGE: $(basename "$0") [OPTIONS]

${NAME} ${VERSION}

A fully automated tool to make periodic backups of PostgreSQL databases.

Options:
    -h  Shows this help
    -d  Run in debug mode (no mail sent)
EOH
}
# }}}

# {{{ Process command line arguments

while getopts "hd" OPTION ; do
    case "${OPTION}" in
        h)
            usage
            exit 0
            ;;
        d)
            DEBUG="yes"
            ;;
        *)
            printf "Try \`%s -h\` to check the command line arguments\n" "$(basename "$0")" >&2
            exit 1
    esac
done
# }}}

# {{{ I/O redirection(s) for logging
exec 6>&1           # Link file descriptor #6 with stdout.
                    # Saves stdout.
exec 7>&2           # Link file descriptor #7 with stderr.
                    # Saves stderr.
exec >  >( logger "out")
exec 2> >( logger "err")
# }}}

# {{{ PreBackup
# Run command before we begin
if [ -n "${PREBACKUP}" ]; then
    log_info "Prebackup command output:"
    ${PREBACKUP} | \
        while IFS= read -r line ; do
            log "  ${line}"
        done
fi
# }}}

# {{{ main()
log_info "${NAME} version ${VERSION}"
log_info "Homepage: ${HOMEPAGE}"
log_info "Backup of Database Server - ${HOST}"

if [ -n "${COMP}" ]; then
    if ! command -v "${COMP}" >/dev/null ; then
        log_warn "Disabling compression, '${COMP}' command not found"
        unset COMP
    fi
fi

if [ "${ENCRYPTION}" = "yes" ] && ! command -v "openssl" >/dev/null ; then
    log_warn "Disabling encryption, 'openssl' command not found"
    ENCRYPTION="no"
fi

log_info "Backup Start: $(date)"
if [ "${DNOM}" = "${DOMONTHLY}" ]; then
    period="monthly"
    rotate="${BRMONTHLY}"
elif [ "${DNOW}" = "${DOWEEKLY}" ]; then
    period="weekly"
    rotate="${BRWEEKLY}"
else
    period="daily"
    rotate="${BRDAILY}"
fi

# If backing up all DBs on the server
if [ "${DBNAMES}" = "all" ]; then
    DBNAMES="$(dblist)"
fi

for db in ${DBNAMES} ; do
    db="${db//%/ / }"
    log_info "Backup of Database (${period}) '${db}'"

    backupdbdir="${BACKUPDIR}/${period}/${db}"
    if [ ! -e "${backupdbdir}" ]; then
        log_debug "Creating Backup DB directory '${backupdbdir}'"
        mkdir -p "${backupdbdir}"
    fi

    cleanup "${BACKUPDIR}" "${db}" "${period}" "${rotate}"

    backupfile="${backupdbdir}/${db}_${DATE}.${EXT}"
    dump "${db}" "${backupfile}"
done
log_info "Backup End: $(date)"

log_info "Total disk space used for ${BACKUPDIR}: $(du -hs "${BACKUPDIR}" | cut -f1)"
# }}}

# {{{ PostBackup
# Run command when we're done
if [ -n "${POSTBACKUP}" ]; then
    log_info "Postbackup command output:"
    ${POSTBACKUP} | \
        while IFS= read -r line ; do
            log "  ${line}"
        done
fi
# }}}

# {{{ cleanup I/O redirections
exec 1>&6 6>&-      # Restore stdout and close file descriptor #6.
exec 2>&7 7>&-      # Restore stdout and close file descriptor #7.
# }}}

# {{{ Reporting
if [ "${DEBUG}" = "no" ] && grep -q '^err|' "${LOG_FILE}" ; then
    (
        printf "*Errors/Warnings* (below) reported during backup on *%s*:\n\n" "${HOST}"
        grep '^err|' "${LOG_FILE}" | cut -d '|' -f 3- | \
        while IFS= read -r line ; do
            printf "  | %s\n" "${line}"
        done
        printf "\n\nFull backup log follows:\n\n"
        grep -v '^...|debug|' "${LOG_FILE}" | \
        while IFS="|" read -r fd level line ; do
            if [ -n "${level}" ]; then
                printf "%8s| %s\n" "*${level}*" "${line}"
            else
                printf "%8s| %s\n" "" "${line}"
            fi
        done
        printf "\nFor more information, try to run %s in debug mode, see \`%s -h\`\n" "${NAME}" "$(basename "$0")"
    ) | mail -s "${NAME} - log" "${MAILADDR}"
fi
# }}}

# {{{ Cleanup and exit()
if [ -s "${LOGERR}" ]; then
    rc=1
else
    rc=0
fi

# Clean up log files
rm -f "${LOG_FILE}"

exit ${rc}
# }}}

# vim: foldmethod=marker foldlevel=0 foldenable