croniter

Warnings

• breaking The `croniter` project was previously declared unmaintained and abandoned by its original author in late 2024 due to concerns about the EU Cyber Resilience Act. It has since been adopted and is now maintained by Pallets-Eco. Users should ensure they are using the `pallets-eco` version and monitor its status if the CRA impacts open source libraries.
  Fix: Ensure installation from the official PyPI `croniter` package, which is now maintained by Pallets-Eco, and update to the latest version (6.x.x) if using an older, unmaintained fork.
• gotcha By default, `croniter` uses 'OR' logic when both 'day of month' and 'day of week' fields are specified in a cron expression, matching standard Vixie-cron behavior. This means a schedule will trigger if *either* the day of month *or* the day of week matches. For 'AND' logic (trigger only if *both* match, like fcron), you must explicitly pass `day_or=False` to the `croniter` constructor.
  Fix: If 'AND' logic is desired for day and day-of-week fields, initialize `croniter` with `croniter(cron_expression, base, day_or=False)`.
• gotcha `croniter` is less strict than some cron implementations regarding ranges for months (e.g., 'APR-JAN') and days of the week (e.g., 'SAT-SUN', 'WED-SUN'). These reverse ranges are interpreted, which might lead to unexpected iterations if a strict cron parser is anticipated.
  Fix: Carefully review cron expressions, especially those with reverse ranges. Validate the generated iterations against expected behavior, or use a more strictly validated cron string if precise adherence to a specific cron flavor is critical.
• gotcha The `is_valid()` method, by default, only performs basic syntax and field range validation. It does not perform cross-field validation (e.g., it will report '31 2 * * *' as valid even though February has no 31st). To enable strict cross-field validation, you must pass `strict=True`.
  Fix: Always use `croniter.is_valid(cron_expression, strict=True)` for comprehensive validation, especially with user-provided cron strings, to prevent parsing impossible dates.
• gotcha The `croniter.match()` method has a default precision of 60 seconds for 5-field expressions and 1 second for 6-field expressions. This means a target `datetime` up to 60 (or 1) seconds *after* the scheduled time will still be considered a match. This can cause issues in scenarios requiring exact time matching.
  Fix: When using `croniter.match()`, be aware of its default precision. For highly precise matching, consider comparing `datetime` objects directly or adjusting the comparison logic.

Install

• pip install croniter Install latest version

Imports

• croniter

  from croniter import croniter

Quickstart

Demonstrates creating a croniter object and retrieving the next matching datetime. It also shows the `day_or` parameter for 'AND' logic between day-of-month and day-of-week fields.

from datetime import datetime
from croniter import croniter

# Example 1: Every 5 minutes
base = datetime(2010, 1, 25, 4, 46)
iter_5min = croniter('*/5 * * * *', base)
print(f"Next occurrence (every 5 min): {iter_5min.get_next(datetime)}")

# Example 2: Every Monday and Friday at 04:02
base = datetime.now()
iter_mf = croniter('2 4 * * mon,fri', base)
print(f"Next occurrence (Mon/Fri 04:02): {iter_mf.get_next(datetime)}")

# Example 3: First day of the month AND a Wednesday
# (using day_or=False for AND logic, like fcron)
base = datetime.now()
iter_and = croniter('2 4 1 * wed', base, day_or=False)
print(f"Next occurrence (1st day AND Wed 04:02): {iter_and.get_next(datetime)}")