#!/usr/bin/env 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

# Email Address to send errors to. If empty errors are displayed on stdout.
MAILADDR="root"

# By default, on Debian systems (and maybe others), only postgres user is
# allowed to access PostgreSQL databases without password.
#
# In order to dump databases we need to run pg_dump/psql commands as postgres
# with su. This setting makes possible to run backups with a substitute user
# using su. If
#
# empty, su usage will be disabled)
SU_USERNAME=

# Username to access the PostgreSQL server
USERNAME="postgres"

# Password settings
# In order to use a password to connect to database create a file
# ${HOME}/.pgpass containing a line like this
#
# hostname:*:*:dbuser:dbpass
#
# replace hostname with the value of ${DBHOST}, dbuser with the value of
# ${USERNAME} and dbpass with the password.

# Host name (or IP address) of PostgreSQL server.
# Use 'localhost' for socket connection or '127.0.0.1' to force TCP connection
DBHOST="localhost"

# Port of PostgreSQL server.
# It is also used if ${DBHOST} is localhost (socket connection) as socket name
# contains port
DBPORT="5432"

# List of database(s) names(s) to backup If you would like to backup all
# databases on the server set DBNAMES="all".
#
# If set to "all" then any new databases will automatically be backed up
# without needing to modify this settings when a new database is created.
#
# If the database you want to backup has a space in the name replace the space
# with a % ("data base" will become "data%base").
DBNAMES="all"

# List of databases to exclude if DBNAMES is not set to all.
DBEXCLUDE=""

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

# Backup directory
BACKUPDIR="/var/backups"

# Include CREATE DATABASE in backups?
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=7

# Which day do you want monthly backups?
# When set to 0, monthly backups are disabled
DOMONTHLY=1

# Backup retention count for daily backups, older backups are removed.
BRDAILY=14

# Backup retention count for weekly backups, older backups are removed.
BRWEEKLY=5

# Backup retention count for monthly backups, older backups are removed.
BRMONTHLY=12

# Compression tool. It could be gzip, pigz, bzip2, xz, zstd or any compression
# tool that supports to read data to be compressed from stdin and outputs them
# to stdout).
# If the tool is not in ${PATH}, the absolute path can be used.
COMP="gzip"

# Compression tools options to be used with COMP
COMP_OPTS=

# Options string for use with pg_dump (see pg_dump manual page).
PGDUMP_OPTS=

# Options string for use with pg_dumpall (see pg_dumpall manual page).
PGDUMPALL_OPTS=

# Backup files extension
EXT="sql"

# Backup files permission
PERM=600

# Minimum size (in bytes) for a dump/file (compressed or not).
# File size below this limit will raise an warning.
MIN_DUMP_SIZE=256

# Enable encryption (asymmetric) with GnuPG.
ENCRYPTION="no"

# Encryption public key (path to the key)
# Export your public key=""
#     gpg --export 0xY0URK3Y1D --output mypubkey.gpg or \
#     gpg --export --armor 0xY0URK3Y1D --output mypubkey.asc
#     then copy mypubkey.asc or mypubkey.gpg to the path pointed by the
#     ${ENCRYPTION_PUBLIC_KEY}.
#
# Decryption
#     gpg --decrypt --output backup.sql.gz backup.sql.gz.enc
#
ENCRYPTION_PUBLIC_KEY=

# Suffix for encyrpted files
ENCRYPTION_SUFFIX=".enc"

# Command or script to execute before backups
PREBACKUP=

# Command or script to execute after backups
POSTBACKUP=
# }}}

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

# {{{ 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="$(printf '%.2i' "${DOMONTHLY}")"

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

# Debug mode
DEBUG="no"

# Encryption prerequisites
GPG_HOMEDIR=

# 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
HOSTNAME="$(uname -n)"
if [[ "${HOSTNAME}" != *.* ]]; then
    HOSTNAME="$(hostname --fqdn)"
fi

HOST="${DBHOST}:${DBPORT}"
if [ "${DBHOST}" = "localhost" ]; then
    HOST="${HOSTNAME}:${DBPORT} (socket)"
fi

CONN_ARGS=()
# }}}

# {{{ 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"
}
# }}}

# {{{ gpg_setup()
gpg_setup() {
    GPG_HOMEDIR="$(mktemp --quiet --directory -t "${NAME}.XXXXXX")"
    chmod 700 "${GPG_HOMEDIR}"
    log_debug "With encryption enabled creating a temporary GnuPG home in ${GPG_HOMEDIR}"
    gpg --quiet --homedir "${GPG_HOMEDIR}" --quick-gen-key --batch --passphrase-file /dev/null "root@${HOSTNAME}"
}
# }}}

# {{{ encryption()
encryption() {
    log_debug "Encrypting using public key ${ENCRYPTION_PUBLIC_KEY}"
    gpg --homedir "${GPG_HOMEDIR}" --encrypt --passphrase-file /dev/null --recipient-file "${ENCRYPTION_PUBLIC_KEY}" 2> >(logger "err" "error")
}
# }}}

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

# {{{ pgdb_init()
pgdb_init () {
    CONN_ARGS=(--port "${DBPORT}")
    if [ "${DBHOST}" != "localhost" ]; then
        CONN_ARGS+=(--host "${DBHOST}")
    fi
    if [ -n "${USERNAME}" ]; then
        CONN_ARGS+=(--username "${USERNAME}")
    fi
}
# }}}

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

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

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

    log_debug "Running command: ${cmd_prog} ${cmd_args[*]}"
    raw_dblist=$(
        if [ -n "${SU_USERNAME}" ]; then
            if ! su - "${SU_USERNAME}" -c "${cmd_prog} ${cmd_args[*]}" 2> >(logger "err" "error"); then
                log_error "Running (as user '${SU_USERNAME}' command '${cmd_prog} ${cmd_args[*]}' has failed"
            fi
        elif ! "${cmd_prog}" "${cmd_args[@]}" 2> >(logger "err" "error"); then
            log_error "Running command '${cmd_prog} ${cmd_args[*]}' has failed"
        fi
    )

    read -r -a dblist <<< "$(
        printf "%s" "${raw_dblist}" | \
            sed -E -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[@]}"
}
# }}}

# {{{ pgdb_dump()
pgdb_dump () {
    local db_name cmd_prog cmd_args pg_args

    db_name="${1}"

    if [ -n "${PGDUMP_OPTS}" ]; then
        IFS=" " read -r -a PGDUMP_ARGS <<< "${PGDUMP_OPTS}"
    else
        PGDUMP_ARGS=()
    fi

    # pg_dumpall options
    if [ -n "${PGDUMPALL_OPTS}" ]; then
        IFS=" " read -r -a PGDUMPALL_ARGS <<< "${PGDUMPALL_OPTS}"
    else
        PGDUMPALL_ARGS=()
    fi

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

    if [ "${#CONN_ARGS[@]}" -gt 0 ]; then
        cmd_args+=("${CONN_ARGS[@]}")
    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
        if ! su - "${SU_USERNAME}" -c "${cmd_prog} ${cmd_args[*]}" 2> >(logger "err" "error"); then
            log_error "Running (as user '${SU_USERNAME}' command '${cmd_prog} ${cmd_args[*]}' has failed"
        fi
    elif ! "${cmd_prog}" "${cmd_args[@]}" 2> >(logger "err" "error"); then
        log_error "Running command '${cmd_prog} ${cmd_args[*]}' has failed"
    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}'"
        pgdb_dump "${db_name}" | compression | encryption > "${dump_file}"
    elif [ -n "${COMP}" ]; then
        log_debug "Dumping (${db_name}) +compress to '${dump_file}'"
        pgdb_dump "${db_name}" | compression > "${dump_file}"
    elif [ "${ENCRYPTION}" = "yes" ]; then
        log_debug "Dumping (${db_name}) +encrypt to '${dump_file}'"
        pgdb_dump "${db_name}" | encryption > "${dump_file}"
    else
        log_debug "Dumping (${db_name}) to '${dump_file}'"
        pgdb_dump "${db_name}" > "${dump_file}"
    fi

    if [ -f "${dump_file}" ]; then
        log_debug "Fixing permissions (${PERM}) on '${dump_file}'"
        chmod "${PERM}" "${dump_file}"
        fsize=$(stat -c '%s' "${dump_file}")
        if [ ! -s "${dump_file}" ]; then
            log_error "Something went wrong '${dump_file}' is empty"
        elif [ "${fsize}" -lt "${MIN_DUMP_SIZE}" ]; then
            log_warn "'${dump_file}' (${fsize} bytes) is below the minimum required size (${MIN_DUMP_SIZE} bytes)"
        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 "${db}_*" | \
        sed -E 's/(^.+([0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{2}h[0-9]{2}m).*$)/\2 \1/' | \
        sort -r | \
        sed -E -n 's/\S+ //p' | \
        tail -n "+${count}" | \
        xargs -L1 rm -fv | \
        while IFS= read -r line ; do
            log_info "${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 [ "${ENCRYPTION}" = "yes" ]; then
    if [ ! -s "${ENCRYPTION_PUBLIC_KEY}" ]; then
        log_warn "Disabling encryption, '${ENCRYPTION_PUBLIC_KEY}' is empty or does not exists"
        ENCRYPTION="no"
    elif ! command -v "gpg" >/dev/null ; then
        log_warn "Disabling encryption, 'gpg' command not found"
        ENCRYPTION="no"
    else
        gpg_setup
        if ! keyinfo="$(gpg --quiet --homedir "${GPG_HOMEDIR}" "${ENCRYPTION_PUBLIC_KEY}" 2>/dev/null)"; then
            log_warn "Disabling encryption, key in '${ENCRYPTION_PUBLIC_KEY}' does not seems to be a valid public key"
            ENCRYPTION="no"
            if command -v "openssl" >/dev/null && openssl x509 -noout -in "${ENCRYPTION_PUBLIC_KEY}" >/dev/null 2>&1; then
                log_warn "public key in '${ENCRYPTION_PUBLIC_KEY}' seems to be in PEM format"
                log_warn "Encryption using openssl is no longer supported: see ${HOMEPAGE}#openssl-encryption"
            fi
        else
            keyfp="$(echo "${keyinfo}" | sed -E -n 's/^\s*([a-z0-9]+)\s*$/\1/pi')"
            keyuid="$(echo "${keyinfo}" | sed -E -n 's/^\s*uid\s+(\S.*)$/\1/pi' | head -n1)"
            log_info "Encryption public key is: 0x${keyfp} (${keyuid})"
        fi
    fi
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 [ "${DBNAMES}" = "all" ]; then
    DBNAMES="$(pgdb_list)"
fi

pgdb_init

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 grep -q '^err|' "${LOG_FILE}"; then
    rc=1
else
    rc=0
fi

if [ "${DEBUG}" = "no" ] && [ ${rc} = 1 ]; then
    (
        printf "*Errors/Warnings* (below) reported during backup on *%s*:\n\n" "${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 "$0")"
    ) > "${LOG_REPORT}"

    if [ -n "${MAILADDR}" ]; then
        mail -s "${NAME} issues on ${HOSTNAME}" "${MAILADDR}" < "${LOG_REPORT}"
    else
        cat "${LOG_REPORT}"
    fi
fi
# }}}

# {{{ Cleanup and exit()
# Cleanup GnuPG home dir
if [ -d "${GPG_HOMEDIR}" ]; then
    rm -rf "${GPG_HOMEDIR}"
fi

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

exit ${rc}
# }}}

# vim: foldmethod=marker foldlevel=0 foldenable