backup-r38-db.sh

backup-r38-db.sh

#!/bin/bash
# Copyright © 2020 Chris Danis
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Usage: r38-backup-db [instance: prod or staging, default prod]

set -euf

[ "$(whoami)" = "r38" ] || exec sudo -u r38 "$(readlink -f "$0")" "$@"

INSTANCE="${1:-prod}"
BASEDIR="/srv/r38/${INSTANCE}/backups"
mkdir -p "$BASEDIR/tmp" "$BASEDIR/by-hash" "$BASEDIR/by-time"
cd "$BASEDIR"

TIMESTAMP="$(date -Isecond | cut -d+ -f1)"  # eg 2020-06-13T04:22:00
DATE="${TIMESTAMP%%T*}"                     # eg 2020-06-13
TMPFILE="$(mktemp tmp/backup.XXXXXX."${TIMESTAMP}".db)"
trap 'rm -f $TMPFILE' EXIT
[ -r "../draft.db" ] && sqlite3 ../draft.db ".backup ${TMPFILE}"

HASH="$(sha256sum "$TMPFILE")"
HASH="${HASH%% *}"
HASH_DIR="by-hash/${HASH:0:2}/${HASH:2:2}" # abcdef1234 --> ab/cd/abcdef1234
mkdir -p "$HASH_DIR"
HASH_FILE="${HASH_DIR}/${HASH}"

if [ ! -f "${HASH_FILE}.gz" ]; then
    mv "$TMPFILE" "$HASH_FILE"
    gzip --best "$HASH_FILE"
fi

mkdir -p "by-time/${DATE}"
ln -s "../../$HASH_FILE.gz" "by-time/${DATE}/${TIMESTAMP}.gz"