rbackup

#!/usr/bin/env sh

# A fairly great backup solution.

ScriptName=${0##*/}
Version=1.0.1
Deps='rsync timeout ping'

EnvConfigFileVar=$(printf '%s_CONFIG' "$ScriptName" | tr '[a-z]' '[A-Z]')
EnvConfigFileValue=$(eval printf '%s' \$$EnvConfigFileVar)
ConfigFile=${EnvConfigFileValue:-$HOME/.config/$ScriptName/config}

[ "$EnvConfigFileValue" ] && ConfigFileStatus="Currently \033[1;34m$EnvConfigFileVar\033[0m=$ConfigFile" || \
    ConfigFileStatus="Currently \033[1;34m$EnvConfigFileVar\033[0m is not set."

HelpMessage="\033[32m$ScriptName\033[0m $Version
Alexander Chaplin Braz <contact@alexchaplinbraz.com>

Can handle multiple backups in series with optional dated versioning and
exclusions file for each backup.

Also handles remote servers by checking connectivity before syncing. If
unavailable, it's skipped and the next backup starts. Same for errors
with the configuration.

Additionally, logging the output of the script is supported.

More info about configuring backup units in the config.

Can set the full path to the configuration file with \033[1;34m$EnvConfigFileVar\033[0m,
but if not set it defaults to: $HOME/.config/$ScriptName/config
$ConfigFileStatus

\033[33mUSAGE:\033[0m
    $ScriptName [FLAG]
    $ScriptName [PATH]

\033[33mFLAGS:\033[0m
    \033[32m-c\033[0m, \033[32m--create-config\033[0m     Create template config. Overwrites existing config.
    \033[32m-h\033[0m, \033[32m--help\033[0m              Print help and exit.
    \033[32m-p\033[0m, \033[32m--print-template\033[0m    Print the template config to stdout.
    \033[32m-v\033[0m, \033[32m--version\033[0m           Print version and exit.

\033[33mARGS:\033[0m
    \033[32m[PATH]\033[0m    Full path to the configuration file.

\033[33mDEPENDENCIES:\033[0m
    $Deps
"

ConfigTemplate="# This is essentially a script that is loaded and run inside $ScriptName to
# get the shell variables. That means you could technically run other code too.
# Avoid doing that if you don't know what you're doing.

# Maximum number of units to loop through.
# Doesn't matter even if it's 1000, just make sure it's not less than the
# largest enabled unit number, since that'd mean the loop won't reach it.
UnitCount=10
# Leave blank or disable logging, write anything to enable.
# This simply redirects all output of $ScriptName to the log file, appending
# everything to the end so it goes from oldest to newest.
EnableLogging=
# Location of the log file.
LogFile=~/.config/$ScriptName/log
# Maximum number of lines to keep in the log. When this amount is reached,
# the oldest lines at the top are stripped. Keep in mind that a normal backup
# without any errors only takes up 19 lines, which is around 565 bytes.
# So the defaul value would allow to hold a little over 1000 transfers
# and the size of the file would be around 0.6 megabytes.
MaxLogLineAmount=20000

# Name shown over stats.
Label1=
# Leave blank to disable this unit, write anything to enable.
Enabled1=
# Full path to backup from. Remember that a trailing slash means the contents of
# the directory, while no trailing slash means the directory itself.
BackupFrom1=
# Full path to backup to.
BackupTo1=
# Full path to exclusions file, with each exclusion on one line.
# Can leave blank to disable.
ExclusionsFile1=
# Full path to directory where to store deleted/modified files.
# Can leave blank to disable.
VersioningDir1=

# Rinse and repeat for as many more backups as needed, keeping in mind that
# a \"unit\" is the group of variables ending with the same number.
Label2=
Enabled2=
BackupFrom2=
BackupTo2=
ExclusionsFile2=
VersioningDir2=

Label3=
Enabled3=
BackupFrom3=
BackupTo3=
ExclusionsFile3=
VersioningDir3=

Label4=
Enabled4=
BackupFrom4=
BackupTo4=
ExclusionsFile4=
VersioningDir4=

"

error() {
    printf "\033[1;31m${2:-ERROR}\033[0m: %s.\nTry '%s --help' for more information.\n" \
        "$1" "$ScriptName" 1>&2
    exit 1
}

info() { printf "\033[1;34m${2:-INFO}\033[0m: %s.\n" "$1" 1>&2; }

error_loop() { printf "\033[1;31m${2:-ERROR}\033[0m: %s.\n" "$1" 1>&2; }

cannot_connect_to() {
    if ! timeout 3 ping -c1 -w1 -q "$1" >/dev/null; [ "$?" -eq 0 ];then
        error_loop "cannot reach '$1'"
        return 0
    else
        return 1
    fi
}

case $1 in
    -h|--help) printf '%b' "$HelpMessage"; exit 0 ;;
    -v|--version) printf '%s\n' "$Version"; exit 0 ;;
    -c|--create-config)
        mkdir -p "${ConfigFile%/*}"
        printf '%s' "$ConfigTemplate" > "$ConfigFile"
        info "template config created at '$ConfigFile'"
        printf 'Read it for instructions on how to set everything up.\n'
        exit 0 ;;
    -p|--print-template) printf '%s' "$ConfigTemplate"; exit 0 ;;
    '') ;;
    *) ConfigFile=$1 ;;
esac

for dep in $Deps; do ! command -v $dep 1>/dev/null && MissingDeps="$MissingDeps $dep"; done
[ "$MissingDeps" ] && error "missing dependencies:$MissingDeps"

[ ! -f "$ConfigFile" ] && error "'$ConfigFile' is not a valid file"

. "$ConfigFile"

run_backups() {
    [ "$EnableLogging" ] && Redirect='2>&1'

    i=1; while [ $i -le ${UnitCount:-10} ]; do
        unset Enabled Label BackupFrom BackupTo ExclusionsFile VersioningDir ExcludeFrom BackupDir \
            BackupFlag Versioning Date ServerFrom ServerTo tmp

        Enabled=$(eval printf '%s' \"\$Enabled$i\")
        Label=$(eval printf '%s' \"\$Label$i\")
        BackupFrom=$(eval printf '%s' \"\$BackupFrom$i\")
        BackupTo=$(eval printf '%s' \"\$BackupTo$i\")
        ExclusionsFile=$(eval printf '%s' \"\$ExclusionsFile$i\")
        VersioningDir=$(eval printf '%s' \"\$VersioningDir$i\")

        i=$(( i + 1 )) && [ -z "$Enabled" ] && continue

        Date=$(date +'%Y-%m-%d.%H-%M-%S')

        printf '\n===== %s | %s =====\n' "$Label" "$Date"

        [ -z "$Label" ]  && error_loop "Label is empty" && continue
        [ -z "$BackupFrom" ]  && error_loop "BackupFrom is empty" && continue
        [ -z "$BackupTo" ]  && error_loop "BackupTo is empty" && continue

        ServerFrom=$(tmp=${BackupFrom##*@}; printf '%s' "${tmp%%:*}")
        [ "$ServerFrom" = "$BackupFrom" ] && unset ServerFrom
        [ "$ServerFrom" ] && cannot_connect_to "$ServerFrom" && continue
        [ -z "$ServerFrom" ] && [ ! -d "$BackupFrom" ] && \
            error_loop "'$BackupFrom' is not a valid BackupTo directory" && continue

        ServerTo=$(tmp=${BackupTo##*@}; printf '%s' "${tmp%%:*}")
        [ "$ServerTo" = "$BackupTo" ] && unset ServerTo
        [ "$ServerTo" ] && cannot_connect_to "$ServerTo" && continue
        [ -z "$ServerTo" ] && [ ! -d "$BackupTo" ] && \
            error_loop "'$BackupTo' is not a valid BackupTo directory" && continue

        [ "$ExclusionsFile" ] && [ ! -f "$ExclusionsFile" ] && \
            error_loop "'$ExclusionsFile' is not a valid ExclusionsFile file" && continue
        [ "$ExclusionsFile" ] && ExcludeFrom="--exclude-from=$ExclusionsFile"

        [ "$VersioningDir" ] && [ ! -d "$VersioningDir" ] && \
            error_loop "'$VersioningDir' is not a valid VersioningDir directory" && continue
        [ "$VersioningDir" ] && Versioning="${VersioningDir%/}/$Date"
        [ "$VersioningDir" ] && mkdir -p "$Versioning"
        [ "$VersioningDir" ] && BackupDir="--backup-dir=$Versioning"
        [ "$VersioningDir" ] && BackupFlag="-b"

        eval rsync -ah --stats --delete-before --delete-excluded \
            $BackupFlag "$BackupDir" "$ExcludeFrom" "$BackupFrom" "$BackupTo" $Redirect

        [ "$VersioningDir" ] && rmdir "$Versioning" 2>/dev/null
    done
}

if [ "$EnableLogging" ]; then
    mkdir -p "${LogFile%/*}"
    run_backups >> "$LogFile" 2>&1
    LogLineCount=$(wc -l "$LogFile")
    if [ ${LogLineCount% *} -gt $MaxLogLineAmount ]; then
        mv "$LogFile" "$LogFile.old"
        tail -n $MaxLogLineAmount "$LogFile.old" > "$LogFile"
        rm "$LogFile.old"
    fi
else
    run_backups
fi