Script to drive Restic

bu

#!/usr/bin/env bash
#
# bu: Backup data to repository.
#
# Type 'bu --help' for help on actions and options.
#
# Configuration of 'bu' is done via environmental variables which can be set by user
# in a particular session or saved to a file and read by 'bu'.
#
# Examples of backup configuration files:
#
#   S3 remote repository:
#
#       export AWS_ACCESS_KEY_ID="your-Wasabi-Access-Key”
#       export AWS_SECRET_ACCESS_KEY="your-Wasabi-Secret-Key”
#       export RESTIC_REPOSITORY="s3:https://s3.wasabisys.com/repo-name"
#       export RESTIC_PASSWORD="speakfriendandenter"
#       export BACKUP_PATHS="$HOME/projects"
#       export RETENTION_POLICY="--keep-daily=31 --keep-monthly=12 --keep-yearly=3"
#       export SNAPSHOT_TITLE="primary_work"
#
#   B2 remote repository:
#
#       export B2_ACCOUNT_ID="your-b2-account-id"
#       export B2_ACCOUNT_KEY="your-b2-account-key"
#       export RESTIC_REPOSITORY="b2:repo-name"
#       export RESTIC_PASSWORD="speakfriendandenter"
#       export BACKUP_PATHS="$HOME/projects"
#       export RETENTION_POLICY="--keep-daily=31 --keep-monthly=12 --keep-yearly=3"
#       export SNAPSHOT_TITLE="primary_work"
#
#   Filesystem repository:
#
#       export RESTIC_REPOSITORY="/media/peregrine/STORAGE1/backups"
#       export RESTIC_PASSWORD="speakfriendandenter"
#       export BACKUP_PATHS="$HOME/projects"
#       export RETENTION_POLICY="--keep-daily=31 --keep-monthly=12 --keep-yearly=3"
#       export SNAPSHOT_TITLE="primary_work"
#
# Examples of usage:
#
#   $ bu -c primary-backup.conf init            # create a new repository
#   $ bu -c primary-backup.conf backup purge    # backup and cleanup
#   $ bu -c primary-backup.conf list            # list snapshots
#   $ bu -c primary-backup.conf check           # check repository integrity
#
# Adapted from:
#
#   https://github.com/erikw/restic-systemd-automatic-backup
#
# Copyright (c) 2018 Jeet Sukumaran
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# Log start time
START_TIME="$(date +"%Y-%m-%d %H:%M:%S")"
echo "-bu: Starting on ${HOSTNAME} at: $START_TIME"

# Exit on failure, pipe failure
# set -e -o pipefail

# Clean up lock if we are killed.
# If killed by systemd, like $(systemctl stop restic), then it kills the whole
# cgroup and all it's subprocesses. However if we kill this script ourselves,
# we need this trap that kills all subprocesses manually.
exit_hook() {
	echo "-bu: In exit_hook(), being killed" >&2
	jobs -p | xargs kill
	$RESTIC_PATH unlock
}
trap exit_hook INT TERM

error_exit() {
    if [[ ! -z $1 ]]
    then
        echo "-bu: $1 returned non-zero exit code: terminating"
    fi
	# jobs -p | xargs kill
    # $RESTIC_PATH unlock 2>/dev/null 1>/dev/null
    exit 1
}

ACTION_CMDS="init backup purge list unlock rebuild prune check"
function join_by { local IFS="$1"; shift; echo "$*"; }
show_help() {
    echo "usage: bu [-c CONFIGURATION-FILE] [OPTIONS] ($(join_by \| $ACTION_CMDS))"
    echo ""
    echo "Backup data to a repository."
    echo ""
    echo "Actions:"
    echo ""
    echo "  init              Initialize (create) the repository."
    echo "  backup            Backup data to repository."
    echo "  purge             Apply dereferencing policy ('forget') and prune."
    echo "  list              List snapshots in repository."
    echo "  check             Check the repository."
    echo "  unlock            Unlock a repository in a stale locked state."
    echo "  rebuild           Rebuild the repository index."
    echo "  prune             Prune the repository."
    echo ""
    echo "Options:"
    echo ""
    echo "  -h, --help        Show help and exit."
    echo "  -c, --config      Path to file with configuration environmental"
    echo "                    variables declared for export. If not specified,"
    echo "                    then environmental variables must be externally"
    echo "                    set prior to invoking program."
    echo "  --ignore-missing  On backup, ignore missing backup paths."
    echo "  --dry-run         Do not actually do anything: just run through"
    echo "                    commands."
}

# Variables to be read/populated based on command line
BACKUP_CONFIGURATION_PATH=""
IS_INIT=""
IS_UNLOCK=""
IS_BACKUP=""
IS_FORGET_AND_PRUNE=""
IS_CHECK=""
IS_REBUILD=""
IS_PRUNE_ONLY=""
IS_LIST=""
IS_DRY_RUN=""
IS_IGNORE_MISSING=""

# Process command line arguments
POSITIONAL_ARGS=()
while [[ $# -gt 0 ]]
do
    key="$1"
    case $key in
        -c|--config)
            shift
            BACKUP_CONFIGURATION_PATH=$1
            shift
            ;;
        -h|--help)
            show_help
            exit
            ;;
        --dry-run)
            IS_DRY_RUN=1
            shift
            ;;
        --ignore-missing)
            IS_IGNORE_MISSING=1
            shift
            ;;
        --ignore-missing)
            IS_IGNORE_MISSING=1
            shift
            ;;
        -*|--*)
            echo "-bu: Unrecognized option: '$key'"
            echo "-bu: See 'bu --help' for supported 'bu' options."
            exit
        ;;
        *)    # unknown option
            POSITIONAL_ARGS+=("$key") # save it in an array for later
            shift # past argument
        ;;
    esac
done
# set -- "${POSITIONAL_ARGS[@]}" # restore positional parameters

# Path to restic
if [[ $IS_DRY_RUN ]]
then
    RESTIC_PATH="echo restic"
    echo "-bu: Running in dry run mode"
else
    RESTIC_PATH=restic
    # RESTIC_PATH="echo restic"
    echo "-bu: restic path is: '$RESTIC_PATH'"
fi

# Expect to get an action command as a positional argument.
if [[ -z $POSITIONAL_ARGS ]]
then
    echo "-bu: Please specify an action: $(join_by , $ACTION_CMDS)"
    exit 1
fi

# Read configuration path
if [[ -n "$BACKUP_CONFIGURATION_PATH" ]]
then
    if [[ -f "$BACKUP_CONFIGURATION_PATH" ]]
    then
        echo "-bu: Reading backup configuration file: '$BACKUP_CONFIGURATION_PATH'"
        source $BACKUP_CONFIGURATION_PATH
        if [[ $? -ne 0 ]]
        then
            echo "-bu: ERROR: failed to read configuration file."
            exit 1
        fi
    else
        echo "-bu: ERROR: Backup configuration file not found: '$BACKUP_CONFIGURATION_PATH'"
        exit 1
    fi
fi

# Check if at least the repository destination is defined
if [[ -z $RESTIC_REPOSITORY ]]
then
    echo "-bu: Environmental variable \$RESTIC_REPOSITORY specifying path to repository not defined"
    exit 1
fi

# Check if at least the repository destination is defined
if [[ -z $BACKUP_PATHS ]]
then
    echo "-bu: Environmental variable \$BACKUP_PATHS specifying path(s) to back up not defined"
    exit 1
fi

# Iterate over positional arguments
for POS_ARG in ${POSITIONAL_ARGS[@]}
do
    case $POS_ARG in
        init)
            shift
            IS_INIT=1
            echo "-bu: Will initialize new repository at: '$RESTIC_REPOSITORY'"
            ;;
        unlock)
            shift
            IS_UNLOCK=1
            echo "-bu: Will unlock repository at: '$RESTIC_REPOSITORY'"
            ;;
        backup)
            shift
            IS_BACKUP=1
            echo "-bu: Will back up to repository at: '$RESTIC_REPOSITORY'"
            ;;
        purge)
            shift
            IS_FORGET_AND_PRUNE=1
            echo "-bu: Will dereference and prune repository at: '$RESTIC_REPOSITORY'"
            ;;
        list)
            shift
            IS_LIST=1
            echo "-bu: Will list snapshots in repository at: '$RESTIC_REPOSITORY'"
            ;;
        rebuild)
            shift
            IS_REBUILD=1
            echo "-bu: Will rebuild index of repository at: '$RESTIC_REPOSITORY'"
            ;;
        prune)
            shift
            IS_PRUNE_ONLY=1
            echo "-bu: Will prune repository at: '$RESTIC_REPOSITORY'"
            ;;
        check)
            shift
            IS_CHECK=1
            echo "-bu: Will check repository at: '$RESTIC_REPOSITORY'"
            ;;
        *)
            echo "-bu: Unrecognized action command: '$POS_ARG'"
            echo "-bu: See 'bu --help' for supported 'bu' options."
            exit
        ;;
    esac
done

BACKUP_TAG="$(echo "$START_TIME" | sed -e 's/://g' | sed -e 's/ /_/g')_${HOSTNAME}"
if [[ -n "$SNAPSHOT_TITLE" ]]
then
    BACKUP_TAG="${BACKUP_TAG}_${SNAPSHOT_TITLE}"
fi
if [[ -z $BACKUP_TAG ]]
then
    echo "-bu: Empty backup tag generated"
    exit 1
fi
echo "-bu: Destination repository: '$RESTIC_REPOSITORY'"

# NOTE start all commands in background and wait for them to finish.
# Reason: bash ignores any signals while child process is executing and thus my trap exit hook is not triggered.
# However if put in subprocesses, wait(1) waits until the process finishes OR signal is received.
# Reference: https://unix.stackexchange.com/questions/146756/forward-sigterm-to-child-in-bash

if [[ $IS_INIT ]]
then
    echo "-bu: Repository initialization starting"
    $RESTIC_PATH init &
    wait $!
    echo "-bu: Repository initialization done"
fi

if [[ $IS_UNLOCK ]]
then
    echo "-bu: Unlocking repository"
    $RESTIC_PATH unlock &
    wait $!
fi

if [[ $IS_BACKUP ]]
then
    # Check if at least one backup path is given
    if [[ -z $BACKUP_PATHS ]]
    then
        echo "-bu: Backup path information not found in \$BACKUP_PATHS"
        exit 1
    fi
    echo "-bu: Backup starting"
    echo "-bu: Backup tag: '$BACKUP_TAG'"
    echo "-bu: Paths to be included:"
    PROPOSED_BACKUP_PATHS="$BACKUP_PATHS"
    BACKUP_PATHS=""
    for BACKUP_PATH in $PROPOSED_BACKUP_PATHS
    do
        if [[ -d $BACKUP_PATH ]]
        then
            echo "-bu:     '$BACKUP_PATH'"
            BACKUP_PATHS="$BACKUP_PATHS $BACKUP_PATH"
        else
            if [[ $IS_IGNORE_MISSING ]]
            then
                echo "-bu:     '$BACKUP_PATH' [NOT FOUND]"
            else
                echo "-bu: ABORTING DUE TO MISSING PATH: '$BACKUP_PATH'"
                exit 1
            fi
        fi
    done
    echo "-bu: Paths to be excluded: $BACKUP_EXCLUDES"
    $RESTIC_PATH backup \
        --one-file-system \
        --tag $BACKUP_TAG \
        $BACKUP_EXCLUDES \
        $BACKUP_PATHS &
    wait $!
    if [[ $? == 1 ]]
    then
        error_exit "'restic backup'"
    fi
    echo "-bu: Backup done"
fi

if [[ $IS_FORGET_AND_PRUNE ]]
then
    if [[ -z $RETENTION_POLICY ]]
    then
        RETENTION_POLICY="--keep-daily 14 --keep-weekly 16 --keep-monthly 18 --keep-yearly 3"
    fi
    echo "-bu: Dereferencing starting"
    echo "-bu: Retention policy: '$RETENTION_POLICY'"
    $RESTIC_PATH forget     \
        --prune             \
        $RETENTION_POLICY   \
        &
    wait $!
    if [[ $? == 1 ]]
    then
        error_exit "'restic forget'"
    fi
    echo "-bu: Purging done"
fi

if [[ $IS_LIST ]]
then
    $RESTIC_PATH snapshots &
    wait $!
    if [[ $? == 1  ]]
    then
        error_exit "'restic list'"
    fi
fi

if [[ $IS_REBUILD ]]
then
    # Rebuild repository for errors.
    echo "-bu: Rebuilding starting"
    $RESTIC_PATH rebuild-index &
    wait $!
    if [[ $? == 1  ]]
    then
        error_exit "'restic rebuild'"
    fi
    echo "-bu: Rebuilding done"
    echo "-bu: Run 'prune' followed by 'check' to complete."
fi

if [[ $IS_PRUNE_ONLY ]]
then
    echo "-bu: Pruning starting"
    $RESTIC_PATH prune
    wait $!
    if [[ $? == 1 ]]
    then
        error_exit "'restic prune'"
    fi
    echo "-bu: Pruning done"
fi

if [[ $IS_CHECK ]]
then
    # Check repository for errors.
    echo "-bu: Checking starting"
    $RESTIC_PATH check &
    wait $!
    if [[ $? == 1  ]]
    then
        error_exit "'restic check'"
    fi
    echo "-bu: Checking done"
fi

END_TIME="$(date --rfc-3339=seconds)"
echo "-bu: Exiting normally at: $END_TIME"

It would be great to add restore support :)