local-crontab

Common errors

• ModuleNotFoundError: No module named 'local_crontab'

  cause The `local-crontab` package was installed, but the import statement uses an incorrect module name or the package is not in Python's `sys.path`.
  fix Ensure the package is installed via `pip install local-crontab`. The correct import statement is `from local_crontab import Converter` (note the underscore in `local_crontab`).

• TypeError: Converter() takes 2 positional arguments but 3 were given

  cause The `Converter` class constructor was called with an incorrect number of arguments.
  fix The `Converter` class expects exactly two arguments: the crontab string and the local timezone string, e.g., `Converter('0 10 * * *', 'America/New_York')`.

• pytz.exceptions.UnknownTimeZoneError: 'Invalid/Unknown' is not a valid timezone

  cause An invalid or unrecognized timezone string was provided to the `Converter` class.
  fix Ensure the timezone string passed to `Converter` is a valid `pytz` timezone name (e.g., 'America/New_York', 'Europe/London'). Consult the `pytz` documentation for a list of supported timezones.

Warnings

• gotcha The library typically generates multiple UTC crontab entries for a single local crontab. This is by design, accounting for Daylight Saving Time (DST) changes throughout the year. Users expecting a single, fixed UTC equivalent might find this behavior unexpected.
  Fix: Understand that the output of `converter.convert()` is a list of crontab strings. Implement logic to select the appropriate UTC crontab based on the current date, or consider external 'dst check' mechanisms if only one active UTC schedule is required year-round.
• gotcha While the library allows converting crontab 'hour and day parts' to a single UTC equivalent, maintaining year-round accuracy through DST changes requires an *external* 'dst check' program. This external tool is not part of the `local-crontab` library.
  Fix: Be aware that the 'single UTC crontab' feature for hour/day parts is a partial solution. If full DST awareness and year-round accuracy are critical, an external mechanism to manage the active UTC schedule is necessary.
• gotcha This `local-crontab` package is a fork and bug-fixed version of an older project by 'UnitedIncome'. While improvements are included, users familiar with or migrating from the original might encounter subtle behavioral differences or API changes not explicitly documented as breaking changes.
  Fix: If migrating from an older 'UnitedIncome' version, review the GitHub repository's commit history and source code for any unlisted changes. Thorough testing of existing workflows is recommended.

Install

• pip install local-crontab Install stable version

Imports

• Converter

  from local_crontab import Converter

Quickstart

Demonstrates how to instantiate the `Converter` class with a local crontab string and its timezone, then use the `convert()` method to get a list of corresponding UTC crontab strings.

from local_crontab import Converter

# Example 1: Convert a crontab from 'America/New_York' to UTC
# This will typically produce two UTC crontabs due to DST changes.
converter_ny = Converter('0 10 * * *', 'America/New_York')
utc_crontabs_ny = converter_ny.convert()
print(f"Original (NY): 0 10 * * *")
print(f"UTC conversions for 'America/New_York': {utc_crontabs_ny}")
# Expected output similar to: ['0 15 * * *', '0 14 * * *'] (order may vary)

# Example 2: Convert a crontab for 'Europe/Berlin'
# Also likely to produce two UTC crontabs due to DST.
converter_berlin = Converter('30 8 * * *', 'Europe/Berlin')
utc_crontabs_berlin = converter_berlin.convert()
print(f"\nOriginal (Berlin): 30 8 * * *")
print(f"UTC conversions for 'Europe/Berlin': {utc_crontabs_berlin}")
# Expected output similar to: ['30 7 * * *', '30 6 * * *'] (order may vary)