[Bug]: Parsing cron schedule failing

[jimmyd-be]

Bug Report Checklist

• I checked existing issues and found no duplicates.
• I have reviewed Watchtower's documentation and confirmed compliance with documented configuration specifications.
• I have restarted Docker, re-pulled the latest image, and confirmed that the issue persists.

Bug Description

Cron schedule parsing is failing when schedule is configured

Steps to Reproduce

1. Start watchtower with WATCHTOWER_SCHEDULE configured
2. Check logs and you can find the error

Expected Behavior

That the container starts without errors and that it will run on the scheduled time

Watchtower Version

v1.17.2

Docker Version

29.5.2

Docker Info (optional)

Docker Compose Configuration

services:
  watchtower:
    container_name: watchtower
    image: nickfedor/watchtower
    restart: always
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      - WATCHTOWER_SCHEDULE="0 0 2 * * *"
      - TZ="Europe/Brussels"
      - WATCHTOWER_NOTIFICATIONS=shoutrrr
      - WATCHTOWER_NOTIFICATION_URL=ntfy://XYZ
      - WATCHTOWER_CLEANUP=true

Docker CLI Command

Debug Logs

time="2026-05-24T08:18:09Z" level=error msg="Scheduled upgrades failed" error="failed to schedule updates: failed to parse int from "0: strconv.Atoi: parsing "\"0": invalid syntax"

Additional Context

No response

[nicholas-fedor]

The use of the double-quotes around the cron schedule is the culprit.
I'll add some logic to help filter this in the future, but using the following should resolve the issue for you: WATCHTOWER_SCHEDULE=0 0 2 * * *