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#!/usr/bin/env python3
# © Copyright 2021-2022, Scott Gasch
"""A helper class for generating thread safe monotonically increasing
id numbers.
"""
import itertools
import logging
# This module is commonly used by others in here and should avoid
# taking any unnecessary dependencies back on them.
logger = logging.getLogger(__name__)
generators = {}
def get(name: str, *, start=0) -> int:
"""
Returns a thread-safe, monotonically increasing id suitable for use
as a globally unique identifier.
>>> import id_generator
>>> id_generator.get('student_id')
0
>>> id_generator.get('student_id')
1
>>> id_generator.get('employee_id', start=10000)
10000
>>> id_generator.get('employee_id', start=10000)
10001
"""
if name not in generators:
generators[name] = itertools.count(start, 1)
x = next(generators[name])
logger.debug("Generated next id %d", x)
return x
if __name__ == '__main__':
import doctest
doctest.testmod()
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