Passing tunnel tokens into cloudflared via Docker Compose secrets

compose.yml

services:
  tunnel:
    build:
      dockerfile: Dockerfile.cloudflared
    restart: unless-stopped
    secrets:
      - tunnel_prod_token

secrets:
  tunnel_prod_token:
    file: /path/to/tunnel/token

Dockerfile.cloudflared

FROM busybox:1.36.1-uclibc as busybox
FROM cloudflare/cloudflared:2023.8.2
COPY --from=busybox /bin/sh /bin/sh
COPY --from=busybox /bin/cat /bin/cat
ENTRYPOINT [ "/bin/sh", "-c", "export TUNNEL_TOKEN=$(cat /run/secrets/tunnel_prod_token) ;  cloudflared --no-autoupdate tunnel run" ]