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aio-libs
janus
Python2019–2025
aio-libs / janus

janus

Thread-safe asyncio-aware queue for Python

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3Distinct people
3Mentions
0Explicit recommenders
971GitHub stars
REPOSITORY AT A GLANCE

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What it is

Thread-safe asyncio-aware queue for Python

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

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This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 5:05:26 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year3 dated mentions

Observed mentions: 2019-02-10 10:12:55 UTC to 2025-12-20 20:25:38 UTC.

0122019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20192020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments20222023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
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PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC101
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC000
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC000
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC000
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC000
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC000
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC211

What Hacker News says

2 sources
x42005e1f·Dec 20, 2025Submission

Show HN: Сulsans – Thread-safe async-aware queue for Python

In my previous post [0], I described how I came to create aiologic. Here, I want to do the same for a derivative library - Сulsans. In October 2024, I started thinking about how to present aiologic queues. Andrew Svetlov's Janus library [1] had been around for quite some time and was much more popular, so I knew that comparisons with it would be inevitable. However, Janus seemed to be in a suspended state: there had been no major changes for three years, and almost all commits during that period were made by Dependabot. So I asked a relevant question [2]. During the discussion, I pointed out Janus' performance issues and stated that they could be solved by implementing queues on top of my primitives. But since Janus is a mature library, such a radical change could not be accepted. Therefore, as proof of concept, I implemented a new librar
Read the rest
y - Culsans. That is how its story began. Over time, both libraries underwent changes. Janus received significant performance improvements in 1.2.0, not least due to my PRs [3]. In 2.0.0, contrary to the above, backward compatibility was broken as a result of the implementation of shutdown methods. And Culsans became an independent library with its own features (which neither aiologic nor Janus have). So, what is Culsans? It is a library that provides a way to communicate within a single process between different threads, different tasks (including from different event loops; asyncio, Curio, Trio, AnyIO - whatever you want), and even different greenlets (eventlet/gevent), all in a single instance. Its queues are fully compatible with the standard queues via Janus-like interfaces (as well as with Janus itself) and provide additional features such as dynamic maxsize. In short, I invite you to try out my library and see for yourself. [0] https://news.ycombinator.com/item?id=46308839 [1] https://github.com/aio-libs/janus [2] https://github.com/aio-libs/janus/issues/679 [3] https://github.com/aio-libs/janus/pull/704
2 points · Open discussion
xg15·Sep 2, 2025
Everything that directly interacts with an event loop object and calls methods such as loop.call_soon() [1]. This is used by most of asyncio's synchronization primitives, e.g. async.Queue. A consequence is that you cannot use asyncio Queues to pass messages or work items between async functions and worker threads. (And of course you can't use regular blocking queues either, because they would block). The only solution is to build your own ad-hoc system using loop.call_soon_threadsafe() or use third-party libs like Janus[2]. [1] https://github.com/python/cpython/blob/e4e2390a64593b33d6556... [2] https://github.com/aio-libs/janus
In Python has had async for 10 years – why isn't it more popular?

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