use variables for a variable path

docker-compose.yml

@@ -148,13 +148,14 @@ services:
     image: registry.git.base23.de/base23/backup/resticker:0.17.0
     environment:
       PRE_COMMANDS: |-
-        cd /sso.base23.de/
+        cd /\${RESTIC_TAG}/
         [[ $($(docker compose &>/dev/null); echo "$?") -eq 0 ]] || apk add --no-cache docker-cli-compose
         docker compose exec -T postgresql pg_dump -U ${PG_USER:-authentik} -d ${PG_DB:-authentik} -f /var/lib/postgresql/backups/${PG_DB:-authentik}.sql
       #RUN_ON_STARTUP: "true"
       BACKUP_CRON: "32 2 * * *"
       RESTIC_REPOSITORY: sftp://${RESTIC_REPO_USER:?Restic repository user is required}@${RESTIC_REPO_ADDRESS:?Restic repository address is requried}:${RESTIC_REPO_PORT:?Restic repository port is required}//backup
-      RESTIC_PASSWORD: ${RESTIC_REPO_PASSWORD:?Restic repository password is required}
+      RESTIC_PASSWORD: '${RESTIC_REPO_PASSWORD:?Restic repository password is required}'
+      RESTIC_TAG: '${RESTIC_TAG:?Restic repository tag is required}'
       RESTIC_BACKUP_SOURCES: /var/lib/postgresql/backups /var/lib/authentik/backups /var/lib/lego/backups
       RESTIC_BACKUP_ARGS: >-
         --tag ${RESTIC_TAG:?Restic tag is required}
@@ -168,8 +169,8 @@ services:
     volumes:
       - ./data/restic/ssh/:/run/secrets/.ssh:ro
       - /var/run/docker.sock:/var/run/docker.sock
-      - ./docker-compose.yml:/sso.base23.de/docker-compose.yml:ro
-      - ./.env:/sso.base23.de/.env:ro
+      - ./docker-compose.yml:/${RESTIC_TAG}/docker-compose.yml:ro
+      - ./.env:/${RESTIC_TAG}/.env:ro
       - backups_db:/var/lib/postgresql/backups:ro
       - ./data/authentik/certs:/var/lib/authentik/backups/certs:ro
       - ./data/authentik/custom-templates:/var/lib/authentik/backups/templates:ro
@@ -183,7 +184,7 @@ services:
       RUN_ON_STARTUP: "true"
       PRUNE_CRON: "2 3 * * * *"
       RESTIC_REPOSITORY: sftp://${RESTIC_REPO_USER:?Restic repository user is required}@${RESTIC_REPO_ADDRESS:?Restic repository address is requried}:${RESTIC_REPO_PORT:?Restic repository port is required}//backup
-      RESTIC_PASSWORD: ${RESTIC_REPO_PASSWORD:?Restic repository password is required}
+      RESTIC_PASSWORD: '${RESTIC_REPO_PASSWORD:?Restic repository password is required}'
       TZ: Europe/Berlin
     volumes:
       - ./data/restic/ssh/:/run/secrets/.ssh:ro