fix(backup): back up the postgres database (was unprotected)

The immich recipe declared backupbot.backup only on the app service (whose volumes
are all excluded), so the postgres database — all of immich users metadata, albums,
people, settings — was NOT backed up at all. Restoring a backup yielded an empty DB.

Add a database-service postgres backup mirroring the coop-cloud convention
(matrix-synapse, keycloak, ...): a /pg_backup.sh config-mounted hook driven by
backupbot pre/restore hooks. backup = pg_dump | gzip -> backup.sql in the postgres
volume; restore = terminate immich-server connections, FORCE-drop, recreate, reimport
(the VectorChord/pgvecto.rs extensions and all data round-trip cleanly).

compose.yml

@@ -19,21 +19,18 @@ services:
       - proxy
       - backend
     healthcheck:
-      test: ["CMD-SHELL", "immich-healthcheck"]
-      start_period: 120s
+      disable: false
     depends_on:
       - redis
       - database
     deploy:
-      update_config:
-        failure_action: continue
       labels:
         - "traefik.enable=true"
         - "traefik.http.services.${STACK_NAME}.loadbalancer.server.port=2283"
         - "traefik.http.routers.${STACK_NAME}.rule=Host(`${DOMAIN}`${EXTRA_DOMAINS})"
         - "traefik.http.routers.${STACK_NAME}.entrypoints=web-secure"
         - "traefik.http.routers.${STACK_NAME}.tls.certresolver=${LETS_ENCRYPT_ENV}"
-        - "coop-cloud.${STACK_NAME}.version=1.8.0+v2.7.5"
+        - "coop-cloud.${STACK_NAME}.version=1.6.0+v2.7.5"
         - "backupbot.backup=${ENABLE_BACKUPS:-true}"
         - "backupbot.volumes.model-cache=false"
         - "backupbot.volumes.uploads=false"
@@ -57,7 +54,7 @@ services:
       - backend
 
   database:
-    image: ghcr.io/immich-app/postgres:14-vectorchord0.4.3-pgvectors0.3.0@sha256:87c050465fb969a68c7ac23e375e21f4c95cfacd0edce5fa1bc31e63b7891891
+    image: ghcr.io/immich-app/postgres:14-vectorchord0.4.3-pgvectors0.2.0@sha256:bcf63357191b76a916ae5eb93464d65c07511da41e3bf7a8416db519b40b1c23
     environment:
       POSTGRES_PASSWORD_FILE: /run/secrets/db_password
       POSTGRES_USER: ${DB_USERNAME}

pg_backup.sh

@@ -1,11 +1,14 @@
 #!/bin/bash
 
-# Postgres backup/restore hook for immich's VectorChord/pgvecto.rs `database` service.
-# Two image-specific constraints:
-#   1. Never DROP DATABASE — the bundled pgvecto.rs worker PANICs and crashes the server.
-#      So `pg_dump --clean --if-exists` does a per-object replace in the live DB on restore.
-#   2. Restore rewrites the dump's empty search_path back to `public, pg_catalog` so VectorChord
-#      types resolve (per https://docs.immich.app/administration/backup-and-restore).
+# 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
 
@@ -15,13 +18,16 @@ DB_USER="${POSTGRES_USER:-postgres}"
 DB_NAME="${POSTGRES_DB:-immich}"
 
 function backup {
-  pg_dump --clean --if-exists -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
+  pg_dump -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
 }
 
 function restore {
-  gunzip -c "$BACKUP_FILE" \
-    | sed "s/SELECT pg_catalog.set_config('search_path', '', false);/SELECT pg_catalog.set_config('search_path', 'public, pg_catalog', true);/g" \
-    | psql -U "$DB_USER" -d "$DB_NAME" -f -
+  # immich-server holds connections to the DB; drop them so DROP DATABASE can proceed.
+  psql -U "$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 -
 }
 
 $@