Atomic Counter

Overview

atomic-counter is a rust library for generating a monotonically increasing sequence of integers. Depending on the particular configuration of the counter, the generated sequence will be produce unique numbers down to the nanosecond, regardless of memory state. E.g. if you quit the process and recreate a new counter >1ns later, your sequence is guaranteed to still be monotonically increasing (but with a gap).

Usage

from atomic_counter import Counter

c = Counter(base_in_nanos)

c.next()  # generate next number in sequence

To create e.g. a daily counter, pass in base=today in nanos. As this is a common occurrence for sequences that reset daily, a convenience function def daily() -> Counter: is provided.

There is also a TimeCounter class provided. A 64 bit unsigned integer is created that is monotonically increasing, and allows for converting to microseconds to serve as a timestamp (up to the year 2112). Will break if more than 4096 calls to "next" are called within a single microsecond (which is almost assuredly never going to be physically possible, every call makes a system call to get the current time).

from atomic_counter import TimeCounter
from datetime import datetime, timezone

c = TimeCounter()

x = c.next()  # generate id
x_time = TimeCounter.to_datetime(x)  # generates the datetime where the value was called.
now = datetime.now(timezone.utc)
assert x_time <= now