Possible memory leak in aiohttp-client instrumentation

Describe your environment

OS: Microsoft Windows 11 Enterprise, 10.0.26100 Build 26100
Python version: Python 3.13.13 (tags/v3.13.13:01104ce, Apr 7 2026, 19:25:48) [MSC v.1944 64 bit (AMD64)
Package version: opentelemetry-instrumentation-aiohttp-client 0.65b0

What happened?

Possible memory leak when instrumenting aiohttp client connections. Every new connection creates a meter at https://github.com/open-telemetry/opentelemetry-python-contrib/blob/466ae4c00de77d1f54f77a9600f1d08eba2306b5/instrumentation/opentelemetry-instrumentation-aiohttp-client/src/opentelemetry/instrumentation/aiohttp_client/__init__.py#L395 and it is never cleaned up.

Steps to Reproduce

This setup is based on the sample code from https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/aiohttp_client/aiohttp_client.html.

import asyncio
import aiohttp
from opentelemetry.instrumentation.aiohttp_client import (
    AioHttpClientInstrumentor
)
import tracemalloc

# Enable instrumentation
AioHttpClientInstrumentor().instrument()


# Create a session and make an HTTP get request
async def get(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url, ssl=False) as response:
            await response.text()

async def main():
    # Enable tracemalloc
    tracemalloc.start()
    before = tracemalloc.take_snapshot()

    for i in range(1000):
        print(f"Request {i+1}")
        await get("<URL>")
        await asyncio.sleep(5)  # Add a small delay

    after = tracemalloc.take_snapshot()
    stats = after.compare_to(before, 'lineno')
    for stat in stats[:10]:
        print(stat)
    tracemalloc.stop()


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

Expected Result

The expected result is no memory leaks.

Actual Result

This is the snapshot diff

\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:163: size=143 KiB (+143 KiB), count=1001 (+1001), average=146 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:581: size=112 KiB (+112 KiB), count=1000 (+1000), average=115 B
\venv\Lib\site-packages\opentelemetry\instrumentation\_semconv.py:697: size=78.1 KiB (+78.1 KiB), count=1000 (+1000), average=80 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:199: size=62.5 KiB (+62.5 KiB), count=1000 (+1000), average=64 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:498: size=54.7 KiB (+54.7 KiB), count=1000 (+1000), average=56 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:200: size=54.7 KiB (+54.7 KiB), count=1000 (+1000), average=56 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:499: size=54.5 KiB (+54.5 KiB), count=997 (+997), average=56 B
\venv\Lib\site-packages\opentelemetry\metrics\_internal\__init__.py:584: size=31.2 KiB (+31.2 KiB), count=1000 (+1000), average=32 B

Additional context

No response

Would you like to implement a fix?

No

Tip

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Start with instrumentation/opentelemetry-instrumentation-aiohttp-client/src/opentelemetry/instrumentation/aiohttp_client/init.py around line 395, then reproduce the reported growth with the provided aiohttp and tracemalloc example. Compare snapshots across repeated sessions and trace the created meters; done means confirming the retention cause and defining a verified fix or documenting why the objects remain allocated.