wordpress/compose.smtp.yml

---
version: "3.8"

services:
  app:
    secrets:
      - smtp_password
    environment:
      - SMTP_HOST
      - SMTP_PORT=${SMTP_PORT:-25}
      - SMTP_AUTH
      - SMTP_TLS
      - MAIL_FROM
      - SMTP_OVERRIDE_FROM

secrets:
  smtp_password:
    name: ${STACK_NAME}_smtp_password_${SECRET_SMTP_PASSWORD_VERSION}
    external: true