feat: channel plugin architecture with decoupled configs

- Add plugin discovery via Python entry_points (group: nanobot.channels)
- Move 11 channel Config classes from schema.py into their own channel modules
- ChannelsConfig now only keeps send_progress + send_tool_hints (extra=allow)
- Each built-in channel parses dict->Pydantic in __init__, zero internal changes
- All channels implement default_config() for onboard auto-population
- nanobot onboard injects defaults for all discovered channels (built-in + plugins)
- Add nanobot plugins list CLI command
- Add Channel Plugin Guide (docs/CHANNEL_PLUGIN_GUIDE.md)
- Fully backward compatible: existing config.json and sessions work as-is
- 340 tests pass, zero regressions
This commit is contained in:
Xubin Ren
2026-03-13 15:26:55 +00:00
committed by Xubin Ren
parent 58389766a7
commit dbdb43faff
26 changed files with 923 additions and 266 deletions

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# Channel Plugin Guide
Build a custom nanobot channel in three steps: subclass, package, install.
## How It Works
nanobot discovers channel plugins via Python [entry points](https://packaging.python.org/en/latest/specifications/entry-points/). When `nanobot gateway` starts, it scans:
1. Built-in channels in `nanobot/channels/`
2. External packages registered under the `nanobot.channels` entry point group
If a matching config section has `"enabled": true`, the channel is instantiated and started.
## Quick Start
We'll build a minimal webhook channel that receives messages via HTTP POST and sends replies back.
### Project Structure
```
nanobot-channel-webhook/
├── nanobot_channel_webhook/
│ ├── __init__.py # re-export WebhookChannel
│ └── channel.py # channel implementation
└── pyproject.toml
```
### 1. Create Your Channel
```python
# nanobot_channel_webhook/__init__.py
from nanobot_channel_webhook.channel import WebhookChannel
__all__ = ["WebhookChannel"]
```
```python
# nanobot_channel_webhook/channel.py
import asyncio
from typing import Any
from aiohttp import web
from loguru import logger
from nanobot.channels.base import BaseChannel
from nanobot.bus.events import OutboundMessage
class WebhookChannel(BaseChannel):
name = "webhook"
display_name = "Webhook"
@classmethod
def default_config(cls) -> dict[str, Any]:
return {"enabled": False, "port": 9000, "allowFrom": []}
async def start(self) -> None:
"""Start an HTTP server that listens for incoming messages.
IMPORTANT: start() must block forever (or until stop() is called).
If it returns, the channel is considered dead.
"""
self._running = True
port = self.config.get("port", 9000)
app = web.Application()
app.router.add_post("/message", self._on_request)
runner = web.AppRunner(app)
await runner.setup()
site = web.TCPSite(runner, "0.0.0.0", port)
await site.start()
logger.info("Webhook listening on :{}", port)
# Block until stopped
while self._running:
await asyncio.sleep(1)
await runner.cleanup()
async def stop(self) -> None:
self._running = False
async def send(self, msg: OutboundMessage) -> None:
"""Deliver an outbound message.
msg.content — markdown text (convert to platform format as needed)
msg.media — list of local file paths to attach
msg.chat_id — the recipient (same chat_id you passed to _handle_message)
msg.metadata — may contain "_progress": True for streaming chunks
"""
logger.info("[webhook] -> {}: {}", msg.chat_id, msg.content[:80])
# In a real plugin: POST to a callback URL, send via SDK, etc.
async def _on_request(self, request: web.Request) -> web.Response:
"""Handle an incoming HTTP POST."""
body = await request.json()
sender = body.get("sender", "unknown")
chat_id = body.get("chat_id", sender)
text = body.get("text", "")
media = body.get("media", []) # list of URLs
# This is the key call: validates allowFrom, then puts the
# message onto the bus for the agent to process.
await self._handle_message(
sender_id=sender,
chat_id=chat_id,
content=text,
media=media,
)
return web.json_response({"ok": True})
```
### 2. Register the Entry Point
```toml
# pyproject.toml
[project]
name = "nanobot-channel-webhook"
version = "0.1.0"
dependencies = ["nanobot", "aiohttp"]
[project.entry-points."nanobot.channels"]
webhook = "nanobot_channel_webhook:WebhookChannel"
[build-system]
requires = ["setuptools"]
build-backend = "setuptools.backends._legacy:_Backend"
```
The key (`webhook`) becomes the config section name. The value points to your `BaseChannel` subclass.
### 3. Install & Configure
```bash
pip install -e .
nanobot plugins list # verify "Webhook" shows as "plugin"
nanobot onboard # auto-adds default config for detected plugins
```
Edit `~/.nanobot/config.json`:
```json
{
"channels": {
"webhook": {
"enabled": true,
"port": 9000,
"allowFrom": ["*"]
}
}
}
```
### 4. Run & Test
```bash
nanobot gateway
```
In another terminal:
```bash
curl -X POST http://localhost:9000/message \
-H "Content-Type: application/json" \
-d '{"sender": "user1", "chat_id": "user1", "text": "Hello!"}'
```
The agent receives the message and processes it. Replies arrive in your `send()` method.
## BaseChannel API
### Required (abstract)
| Method | Description |
|--------|-------------|
| `async start()` | **Must block forever.** Connect to platform, listen for messages, call `_handle_message()` on each. If this returns, the channel is dead. |
| `async stop()` | Set `self._running = False` and clean up. Called when gateway shuts down. |
| `async send(msg: OutboundMessage)` | Deliver an outbound message to the platform. |
### Provided by Base
| Method / Property | Description |
|-------------------|-------------|
| `_handle_message(sender_id, chat_id, content, media?, metadata?, session_key?)` | **Call this when you receive a message.** Checks `is_allowed()`, then publishes to the bus. |
| `is_allowed(sender_id)` | Checks against `config["allowFrom"]`; `"*"` allows all, `[]` denies all. |
| `default_config()` (classmethod) | Returns default config dict for `nanobot onboard`. Override to declare your fields. |
| `transcribe_audio(file_path)` | Transcribes audio via Groq Whisper (if configured). |
| `is_running` | Returns `self._running`. |
### Message Types
```python
@dataclass
class OutboundMessage:
channel: str # your channel name
chat_id: str # recipient (same value you passed to _handle_message)
content: str # markdown text — convert to platform format as needed
media: list[str] # local file paths to attach (images, audio, docs)
metadata: dict # may contain: "_progress" (bool) for streaming chunks,
# "message_id" for reply threading
```
## Config
Your channel receives config as a plain `dict`. Access fields with `.get()`:
```python
async def start(self) -> None:
port = self.config.get("port", 9000)
token = self.config.get("token", "")
```
`allowFrom` is handled automatically by `_handle_message()` — you don't need to check it yourself.
Override `default_config()` so `nanobot onboard` auto-populates `config.json`:
```python
@classmethod
def default_config(cls) -> dict[str, Any]:
return {"enabled": False, "port": 9000, "allowFrom": []}
```
If not overridden, the base class returns `{"enabled": false}`.
## Naming Convention
| What | Format | Example |
|------|--------|---------|
| PyPI package | `nanobot-channel-{name}` | `nanobot-channel-webhook` |
| Entry point key | `{name}` | `webhook` |
| Config section | `channels.{name}` | `channels.webhook` |
| Python package | `nanobot_channel_{name}` | `nanobot_channel_webhook` |
## Local Development
```bash
git clone https://github.com/you/nanobot-channel-webhook
cd nanobot-channel-webhook
pip install -e .
nanobot plugins list # should show "Webhook" as "plugin"
nanobot gateway # test end-to-end
```
## Verify
```bash
$ nanobot plugins list
Name Source Enabled
telegram builtin yes
discord builtin no
webhook plugin yes
```