--- version: "3.8" services: app: environment: - MAILER_ADAPTER - SMTP_HOST_ADDR - MAILER_EMAIL - MAILER_NAME - SMTP_HOST_PORT - SMTP_USER_NAME - SMTP_USER_PWD - SMTP_HOST_SSL_ENABLED secrets: - smtp_password secrets: smtp_password: name: ${STACK_NAME}_smtp_password_${SECRET_SMTP_PASSWORD_VERSION} external: true