Metadata-Version: 2.4
Name: codechu-events
Version: 0.2.0
Summary: Thread-safe multi-channel event bus with glob filtering, backpressure, and sync/async iteration.
Author: Codechu
License: MIT License
        
        Copyright (c) 2026 Codechu
        
        Permission is hereby granted, free of charge, to any person obtaining a copy
        of this software and associated documentation files (the "Software"), to deal
        in the Software without restriction, including without limitation the rights
        to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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        The above copyright notice and this permission notice shall be included in all
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        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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Project-URL: Homepage, https://github.com/codechu/events-py
Project-URL: Source, https://github.com/codechu/events-py
Project-URL: Issues, https://github.com/codechu/events-py/issues
Keywords: event-bus,pubsub,publish-subscribe,thread-safe,asyncio
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Topic :: Software Development :: Libraries
Requires-Python: >=3.10
Description-Content-Type: text/markdown
License-File: LICENSE
Provides-Extra: dev
Requires-Dist: pytest>=7.0; extra == "dev"
Requires-Dist: pytest-cov>=4.1; extra == "dev"
Requires-Dist: ruff>=0.4; extra == "dev"
Dynamic: license-file

```text
              .    .  c o d e c h u  .    .
           .   \  |  /  e v e n t s  \  |   .
        ((((( ── ((•)) ──────────── ((•)) ── )))))
           '   /  |  \                /  |   '
              '    '   scan.*   ui.click    '
```

> *Thread-safe multi-channel pub/sub — emit from anywhere, listen everywhere.*

# codechu-events

Thread-safe multi-channel event bus for Python. Pure stdlib, ~150 LOC.

```bash
pip install codechu-events
```

## What it gives you

- **Multi-channel pub/sub** with glob-pattern filtering: `["scan.*", "ui.click"]`
- **Thread-safe** — emit from any thread, never blocks
- **Bounded queues** per subscriber — slow consumers drop events, fast publishers never wait
- **Sync + async iteration** — `for ev in sub:` or `async for ev in sub.aiter():`
- **Context manager** for clean unsubscribe: `with bus.subscribe_ctx([...]) as sub:`
- **Heartbeat** support for dead-connection detection on idle channels
- **Resource limits** — max subscribers + max queue depth, bounded by design
- **Stats** for monitoring (subscriber count, drop count, queue depth)

## Quick examples

### Basic usage

Construct a `Bus()` explicitly — there is no module-level default, so
ownership and lifetime stay in the caller's hands.

```python
from codechu_events import Bus

bus = Bus()

with bus.subscribe_ctx(["scan.*"]) as sub:
    bus.emit("scan.started", path="/home")
    bus.emit("scan.progress", count=42)
    bus.emit("scan.finished", count=128, ok=True)
    bus.emit("foo.bar")  # filtered out
    for ev in sub:
        print(ev["event"], ev)
```

### Multiple isolated buses

A single process can run multiple independent buses — useful for
separating domains (e.g. UI events vs telemetry) or for testing:

```python
from codechu_events import Bus

ui_bus = Bus()
telemetry_bus = Bus(max_subscribers=128)  # larger cap for telemetry

ui_sub = ui_bus.subscribe(["ui.*"])
telemetry_sub = telemetry_bus.subscribe(["metric.*"])

ui_bus.emit("ui.click", button="ok")
telemetry_bus.emit("metric.fps", value=58)
# ui_sub only sees ui.click; telemetry_sub only sees metric.fps
```

### Custom subscription class (field-based filter)

For filtering beyond glob, subclass `Subscription` and override `matches()`:

```python
from codechu_events import Bus, Subscription

class PanelFilter(Subscription):
    """Only events with event['panel'] == 'suggestion'."""

    def matches(self, event_type, event=None):
        if event is None:
            return True  # cheap type-check pass; final check at push
        return event.get("panel") == "suggestion"

bus = Bus()
sub = bus.subscribe(["*"], subscription_class=PanelFilter)
bus.emit("scan.started", panel="suggestion")   # delivered
bus.emit("scan.started", panel="treemap")      # rejected
```

### Async iteration

```python
import asyncio
from codechu_events import Bus

bus = Bus()

async def consume():
    with bus.subscribe_ctx(["scan.*"], heartbeat_sec=5.0) as sub:
        async for ev in sub.aiter():
            print(ev)

asyncio.run(consume())
```

## API reference

### `Bus`

| Method | Purpose |
|---|---|
| `Bus(max_subscribers=64, queue_max=200)` | Construct an independent bus. |
| `bus.emit(event_type, **fields)` | Publish event. Never blocks. |
| `bus.subscribe(types=["*"], heartbeat_sec=5.0)` | Create a Subscription. Caller must `unsubscribe()`. |
| `bus.subscribe_ctx(types, heartbeat_sec=5.0)` | Context manager (auto-unsubscribe on exit). |
| `bus.unsubscribe(sub)` | Idempotent removal + `sub.close()`. |
| `bus.stats()` | Dict with subscriber count, total emitted, drop counts. |
| `bus.subscriber_count()` | Active subscription count. |
| `bus.reset()` | Close all subscriptions and zero counters. |

### `Subscription`

| Member | Purpose |
|---|---|
| `for ev in sub:` | Sync blocking iteration. Auto-emits `_keepalive` on idle. |
| `async for ev in sub.aiter():` | Async iteration with event loop. |
| `sub.dropped` | Count of events dropped due to slow consumer. |
| `sub.received` | Count of events accepted. |
| `sub.close()` | Stop iteration (sentinel injected). |

## Resource limits

| Constant | Default | Tweakable |
|---|---|---|
| `QUEUE_MAX` | 200 | Max events per subscriber queue (drops on overflow) |
| `MAX_SUBSCRIBERS` | 64 | Max concurrent subscribers |
| `DEFAULT_HEARTBEAT_SEC` | 5.0 | Idle keepalive interval |

Exceeding `MAX_SUBSCRIBERS` raises `SubscriberLimitExceeded`.

## License

MIT — see [LICENSE](LICENSE).

Part of [Codechu](https://github.com/codechu).
