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Pool - Methods in Py-Cachify¶

The `size()` Method¶

The size() method returns the current number of occupied slots in the pool. Use it to monitor pool utilization or make decisions before attempting to acquire.

Asynchronous Usage¶

import asyncio

from py_cachify import init_cachify, pool


init_cachify()


async def main() -> None:
    worker_pool = pool(key='monitor-pool', max_size=3)

    print(f'Pool size before: {await worker_pool.asize()}')

    async with worker_pool:
        print(f'Pool size during: {await worker_pool.asize()}')

    print(f'Pool size after: {await worker_pool.asize()}')


if __name__ == '__main__':
    asyncio.run(main())

python main.py# The outputPool size before: 0
Pool size during: 1
Pool size after: 0

Synchronous Usage¶

from py_cachify import init_cachify, pool


init_cachify()


worker_pool = pool(key='sync-monitor', max_size=5)

print(f'Pool size: {worker_pool.size()}')

with worker_pool:
    print(f'Pool size during: {worker_pool.size()}')

Method Reference¶

Method	Context	Returns
`size()`	Synchronous	`int`: current occupied slot count
`asize()`	Asynchronous	`int`: current occupied slot count

Both methods return the count after cleaning up expired slots, so the number reflects actual available capacity.

Practical Example: Load Shedding¶

Use size() to implement load shedding - rejecting work when the pool is near capacity:

import asyncio

from py_cachify import init_cachify, pool


init_cachify()


async def process_with_backpressure(task_id: str, worker_pool) -> None:
    current_size = await worker_pool.asize()
    max_size = worker_pool._max_size  # Accessing internal attribute for threshold

    # Reject if pool is 80% full
    if current_size >= max_size * 0.8:
        print(f'Task {task_id}: Server busy, try again later')
        return

    async with worker_pool:
        print(f'Task {task_id}: Processing')
        await asyncio.sleep(0.5)


async def main() -> None:
    worker_pool = pool(key='backpressure-pool', max_size=10)

    # Simulate many incoming tasks
    tasks = [process_with_backpressure(f'task-{i}', worker_pool) for i in range(15)]
    await asyncio.gather(*tasks)


if __name__ == '__main__':
    asyncio.run(main())

What's Next¶

We will see how to use pools as decorators with the @pooled() decorator and handle full pool scenarios with callbacks.