Cron Schedule Parser

Cron Schedule Parser

Prerequisites & Dependencies

• Python 3.10+ (for cron expression parsing)
• No external runtime dependencies; pure-Python cron library optional

Execution Steps

1. Identify the cron expression format: Determine if the input is a standard 5-part cron (minute hour day month weekday) or 6-part format (including seconds).

2. Parse the cron expression: Use a cron library or manual parsing to extract the five (or six) time fields: minute, hour, day-of-month, month, day-of-week.

3. Convert to cron format: If the input is in natural language (e.g., "every hour", "first Monday of the month"), translate it into the standard cron five-part format.

4. Validate the cron expression: Check that the parsed values are valid (e.g., minute 0-59, hour 0-23, day-of-month 1-31, month 1-12, weekday 0-6).

5. Output the cron schedule: Produce the cron expression string that can be used in crontab files or scripts.

6. Example outputs:

   • "Every hour" → 0 * * * *
   • "Daily at 8am" → 0 8 * * *
   • "First Monday of every month" → 0 0 * * 1
   • "Every 15 minutes" → */15 * * * *

npm i node-cron

import croniter
from datetime import datetime

base = datetime.now()
schedule = croniter.croniter('0 * * * *', base)
next_time = schedule.get_next(datetime)

CLI Usage

cron-schedule-parser "every hour"
# Output: 0 * * * *