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Cynic is a simple command-line tool for inspecting and exercising Cyphal networks.

Cynic is built for use with Cyphal v1.1, which introduces named topics. It is fully interoperable with Cyphal/CAN v1.0 via pinned topics, where the topic name is constructed from its subject-ID, like 1234#1234.

Usage

Install:

pip install cyphal-cynic

Run cn --help for full usage info, or read the code -- it is simple and compact. Some basic examples are shown below.

List topics visible in the network

cn ls
cn --can=can0 ls
cn --can=COM8 --bitrate=125000 ls

Publish/subscribe

printf '\x01\x02' | cn pub topic/foo
cn sub -o raw topic/foo > messages.bin

Set defaults per directory in cynic.toml, or use environment variables:

can = "/dev/serial/by-id/usb-Zubax*Babel*if00"  # or SocketCAN iface name
bitrate = 1_000_000
dsdl_root = ["/home/user/public_regulated_data_types/uavcan", "/home/user/zubax_dsdl"]

RPC/streaming

Send a request, print response(s):

cn req topic/foo/bar --io=zubax/primitive/String1K.1.0.dsdl -- 'Hello world!'

Showcase

Firmware update via Cyphal/CAN

Put this in ./cynic.toml so that you don't have to say --can=slcan0 with every command (optional):

can = "slcan0"  # Can also be a file wildcard for SLCAN

Run the file server in the background (or in a second terminal); the topic name here is arbitrarily chosen as fwupd:

cn fs fwupd &

Command the remote node to download the specified firmware file from topic fwupd:

echo 'upd com.zubax.fluxgrip-1-1.0.41c608fbec4f54d9.16c6d0fc4c1e972a.app.release.bin fwupd' | \
    cn pub -i ~/zubax/zubax_dsdl/zubax/primitive/String256.1.0.dsdl command