nus-logger 0.0.2

Auto-reconnecting Nordic UART Service (NUS) BLE logger.

NUS Logger

Auto‑reconnecting Nordic UART Service (NUS) BLE log collector for Zephyr / nRF Connect SDK devices.

PyPI · Issues · MIT License

Features

• Zero-config CLI: discover, connect, stream logs.
• Automatic reconnect with exponential backoff.
• Optional UTC or local timestamps.
• Optional raw hex dump alongside decoded text.
• Append to logfile (external rotation friendly).
• Works on Windows, Linux, macOS via the host Bluetooth stack (bleak).
• Small typed library for embedding / automation.

Installation

pip install nus-logger

Requires Python 3.9+.

Upgrade in place:

pip install -U nus-logger

Quick Start (CLI)

# 1. List advertising NUS devices
nus-logger --list

# 2. Connect by (partial) name, show UTC timestamps, also log to file
nus-logger --name my-device --ts --logfile logs/session.txt

# 3. Show local timestamps and raw hex dump
nus-logger --name my-device --ts-local --raw

Module mode (equivalent):

python -m nus_logger --name my-device --ts

Press Ctrl-C to stop; the tool will attempt automatic reconnection until max retries.

Common Options

--list                 List visible devices and exit
--name SUBSTR          Match advertising name (env: NUS_NAME)
--filter-addr SUBSTR   Prefer address containing substring
--ts / --ts-local      Add UTC or local timestamps
--raw                  Show hex bytes alongside each decoded line
--logfile PATH         Append text lines to file (env: NUS_LOGFILE)
--timeout SECS         Scan/connect timeout (env: NUS_TIMEOUT)
--backoff SECS         Initial reconnect backoff (env: NUS_BACKOFF, grows to 15s)
--max-retries N        Stop after N failed reconnects (env: NUS_MAX_RETRIES)
--verbose              Dump discovered services / characteristics once

Environment variables override flags when flags are omitted.

Programmatic Use

import asyncio
from nus_logger.ble_nus import NUSClient

async def main():
	client = NUSClient(name_substring="my-device")
	await client.connect()
	try:
		async for line in client.iter_lines():  # yields decoded UTF-8 log lines
			print(line)
			if "READY" in line:
				await client.write(b"ping\n")  # optional upstream write
	finally:
		await client.disconnect()

asyncio.run(main())

See nus_logger.nus_logger:main for full CLI orchestration (reconnect logic, backoff, etc.). Higher level automation can use NUSLoggerController for managed sessions.

Typical Workflow with Zephyr / nRF Connect

1. Enable the Nordic UART Service in your firmware (e.g. CONFIG_BT_NUS=y).
2. Print logs normally (Zephyr logging routed to the NUS TX characteristic).
3. Start nus-logger to capture and persist logs.
4. Use --raw if debugging binary framing / encoding issues.

Troubleshooting

Situation	Hint
No devices on Windows	Toggle Bluetooth off/on or airplane mode, verify advertising.
Linux permission errors	Ensure user in bluetooth group or grant CAP_NET_RAW to Python binary.
macOS permission prompt	Allow Bluetooth access in System Settings > Privacy & Security > Bluetooth.
Frequent disconnects	Reduce distance / interference; backoff resets after ~60s stable link.
Mixed devices with similar names	Use --filter-addr to prefer a known address substring.

Development

git clone https://github.com/smnmsr/nus-logger.git
cd nus-logger
pip install -e .[dev]
pytest

Linting is intentionally minimal; contributions should keep the code small and dependency‑light.

Versioning & Compatibility

The public surface is the CLI plus the NUSClient / NUSLoggerController classes. Minor releases may add kwargs/features; removals will occur only in a major bump following semantic versioning principles.

License

MIT License © 2025 Simon M. See LICENSE file for full text.

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