pyleak

library0.2.0pypypi✓ verified 85d ago

Pyleak is a Python library inspired by Go's goleak, designed to detect leaked asyncio tasks, threads, and event loop blocking in asynchronous Python applications. The current version is 0.2.0, with frequent minor and patch releases, indicating active development.

testing observability

pip install pyleak

github ↗package ↗

INSTALL

IMPORT

SIG · PYLEAK

pyleak

testingpythonv0.2.0

Install

1.7s avg

Import

—

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.2.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.000s · 18.5MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 1.7s · import 0.000s · 19MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

no_task_leaks

✓ from pyleak import no_task_leaks

✗ from pyleak import LeakDetector

no_thread_leaks

✓ from pyleak import no_thread_leaks

no_event_loop_blocking

✓ from pyleak import no_event_loop_blocking

This example demonstrates how to use `LeakDetector` to identify unawaited or long-running asyncio tasks that are not properly shut down, which pyleak considers a leak. Running this code will raise an `AssertionError` at the end of the `async with LeakDetector():` block.

import asyncio from pyleak import LeakDetector async def create_leak(): # A task that runs forever, simulating a leak async def forever_task(): while True: await asyncio.sleep(100) asyncio.create_task(forever_task()) async def main(): async with LeakDetector(): await create_leak() print("This will run, but a leak was created.") # LeakDetector exits, will raise AssertionError if leaks are found print("LeakDetector exited, no assertion was raised (this line won't be reached if a leak is present).") if __name__ == "__main__": # To see the AssertionError from the leak: # asyncio.run(main()) # To avoid the assertion for demonstration: try: asyncio.run(main()) except AssertionError as e: print(f"Caught expected leak: {e}")

Debug

Known issues

breaking`no_event_loop_blocking` API changed from decorator/function to an async context manager.

fix

Update usage from `@no_event_loop_blocking` or `no_event_loop_blocking()` to `async with no_event_loop_blocking():`.

affects: >=0.2.0

gotchaFor best results and detailed stack traces when detecting asyncio leaks or blocking, it is recommended to enable asyncio debug mode.

fix

Run your application with `asyncio.run(main(), debug=True)` or set the `PYTHONASYNCIODEBUG` environment variable to `1`.

affects: All versions

gotchaUsing `LeakDetector` without properly shutting down or cancelling all expected long-running background tasks will result in false positives (AssertionError).

fix

Ensure all asyncio tasks, threads, and resources are correctly cleaned up or awaited before the `LeakDetector` context exits. For intentional long-lived tasks, consider using `pyleak.set_allow_extra_tasks` for specific test scenarios, though this should be used cautiously.

affects: All versions

gotcha`CombinedLeakDetector` in versions prior to 0.1.16 could lead to false positive warnings.

fix

Upgrade pyleak to version 0.1.16 or newer to benefit from fixes addressing false positives in `CombinedLeakDetector`.

affects: <0.1.16

Upgrade

Version history

0.2.0latest on PyPI · released Jan 29, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

19 hits · last 30 days

node

OpenAI (training)

Amazon

Resources

githubhttps://github.com/deepankarm/pyleak ↗

packagehttps://pypi.org/project/pyleak/ ↗