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gador/migrate_mongodb.sh

Created February 23, 2023 13:06
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mongodb migration for NixOS update to 23.05
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migrate_mongodb.sh
#! /usr/bin/env nix-shell
#! nix-shell -i bash -p bash
kill_mongo () {
set +e
sleep 5 # wait for previous processes to come to an end
echo "terminating mongod ..."
pkill mongod
sleep 5
pgrep mongod
if [ "$?" -eq 0 ]; then
# really kill mongod
echo "mongod was not yet terminated. Killing it now ..."
pkill -9 mongod
sleep 5
fi
set -e
}
echo
echo "---------------------------------------------"
echo "This script backs up the data from Unifi and migrates it to mongodb-4_4"
echo "This will cause a build of mongodb-4_2 and mongodb-4_4 on your system,"
echo "since those are not cached upstream. Prepare for a longer wait time."
echo
echo "The following variables can be set by environment variables"
UNIFI_DIR="${UNIFI_DIR:-/var/lib/unifi}"
UNIFI_DB_DIR="${UNIFI_DIR}/data/db"
UNIFI_LOG="${UNIFI_LOG:-/var/log/unifi/repair.log}"
BACKUP_DIR="${BACKUP_DIR:-/tmp/mongodump}"
echo "UNIFI_DIR=$UNIFI_DIR"
echo "UNIFI_LOG=$UNIFI_LOG"
echo "BACKUP_DIR=$BACKUP_DIR"
echo "---------------------------------------------"
read -p "Are those correct? " -n 1 -r
echo
if [[ ! $REPLY =~ ^[Yy]$ ]]
then
exit 1
fi
echo
echo "If the migration does not work, please have a look at the log file"
echo "($UNIFI_LOG)"
echo
set -e
if [ "$EUID" -ne 0 ]
then echo "Please run as root"
exit 1
fi
# When the system is already upgraded, mongodb cannot read the old data and will fail to start
# which causes the unifi service to hang. This will cause a delay when stopping the service
echo "---------------------------------------------"
echo "Stopping running unifi service. It is normal that this will take up to a few minutes..."
echo "---------------------------------------------"
systemctl stop unifi.service
echo "---------------------------------------------"
echo "Backup old data dir ($UNIFI_DB_DIR) ..."
echo "---------------------------------------------"
cp -avr $UNIFI_DB_DIR ${UNIFI_DB_DIR}_bak
# Repair and dump database
echo "---------------------------------------------"
echo "Starting mongodb-3_4 repair ..."
echo "---------------------------------------------"
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-3_4 -c "mongod" --dbpath $UNIFI_DB_DIR --logpath $UNIFI_LOG --repair
echo "---------------------------------------------"
echo "Starting mongodb-3_4 and dump the database to $BACKUP_DIR ..."
echo "---------------------------------------------"
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-3_4 -c "mongod" --dbpath $UNIFI_DB_DIR --logpath $UNIFI_LOG --journal --fork
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-tools -c "mongodump" --out=$BACKUP_DIR
kill_mongo
echo "---------------------------------------------"
echo "Remove old data dir ($UNIFI_DB_DIR) and recreate it ..."
echo "---------------------------------------------"
rm -rf $UNIFI_DB_DIR
mkdir $UNIFI_DB_DIR
# mongo 4_4 cannot read the database of mongo 3_4
# Therefore, we need to upgrade to mongo_4_2 first
echo "---------------------------------------------"
echo "Starting mongodb-4_2 and restore the database ..."
echo "---------------------------------------------"
export NIXPKGS_ALLOW_UNFREE=1; nix --extra-experimental-features "nix-command flakes" shell --impure github:nixos/nixpkgs/22.11#mongodb-4_2 -c "mongod" --dbpath $UNIFI_DB_DIR --logpath $UNIFI_LOG --journal --fork
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-tools -c "mongorestore" $BACKUP_DIR
sleep 5 # wait for the restore to be done completly
echo "---------------------------------------------"
echo "Dump the database to ${BACKUP_DIR}_2 ..."
echo "---------------------------------------------"
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-tools -c "mongodump" --out=${BACKUP_DIR}_2
kill_mongo
echo "---------------------------------------------"
echo "Starting mongodb-4_4 and repair the database ..."
echo "---------------------------------------------"
export NIXPKGS_ALLOW_UNFREE=1; nix --extra-experimental-features "nix-command flakes" shell --impure github:nixos/nixpkgs/22.11#mongodb-4_4 -c "mongod" --dbpath $UNIFI_DB_DIR --logpath $UNIFI_LOG --repair
echo "---------------------------------------------"
echo "Starting mongodb-4_4 and restore the database from ${BACKUP_DIR}_2 ..."
echo "---------------------------------------------"
export NIXPKGS_ALLOW_UNFREE=1; nix --extra-experimental-features "nix-command flakes" shell --impure github:nixos/nixpkgs/22.11#mongodb-4_4 -c "mongod" --dbpath $UNIFI_DB_DIR --logpath $UNIFI_LOG --journal --fork
nix --extra-experimental-features "nix-command flakes" shell github:nixos/nixpkgs/22.11#mongodb-tools -c "mongorestore" ${BACKUP_DIR}_2
kill_mongo
echo "---------------------------------------------"
echo "Fixing permissions..."
echo "---------------------------------------------"
chown -R unifi:unifi $UNIFI_DIR
echo "---------------------------------------------"
echo "Cleaning up..."
echo "---------------------------------------------"
rm -rf $BACKUP_DIR
rm -rf ${BACKUP_DIR}_2
echo "---------------------------------------------"
echo "The original database is still present in ${UNIFI_DB_DIR}_bak. If something didn't work, you can restore it from there"
echo "---------------------------------------------"
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