#!/bin/bash

# Postgres backup/restore hook for the immich `database` service (VectorChord/pgvecto.rs image).
# Invoked by backupbot-two via the deploy labels:
#   backupbot.backup.pre-hook    = "/pg_backup.sh backup"
#   backupbot.backup.volumes.postgres.path = "backup.sql"
#   backupbot.restore.post-hook  = "/pg_backup.sh restore"
# Backup dumps the immich DB to backup.sql (gzip) inside the postgres volume; backupbot then
# archives that file. Restore reads it back and reimports. immich-server keeps TCP connections
# open to the DB, so restore must terminate them and FORCE-drop before recreating (the matrix-synapse
# pg_hba "local trust" trick does not cover networked connections).

set -e

BACKUP_FILE='/var/lib/postgresql/data/backup.sql'
export PGPASSWORD=$(cat "${POSTGRES_PASSWORD_FILE:-/run/secrets/db_password}")
DB_USER="${POSTGRES_USER:-postgres}"
DB_NAME="${POSTGRES_DB:-immich}"

function backup {
  pg_dump -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
}

function restore {
  # immich-server holds connections to the DB; drop them so DROP DATABASE can proceed.
  psql -U "$DB_USER" -d postgres -c \
    "SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname='${DB_NAME}' AND pid<>pg_backend_pid();"
  psql -U "$DB_USER" -d postgres -c "DROP DATABASE ${DB_NAME} WITH (FORCE);"
  createdb -U "$DB_USER" "$DB_NAME"
  gunzip -c "$BACKUP_FILE" | psql -U "$DB_USER" -d "$DB_NAME" -1 -v ON_ERROR_STOP=1 -f -
}

$@