csyn

csyn is a ROS-like command-line tool for Synapse systems using Zenoh for transport and FlatBuffers for payloads.

The command grammar intentionally mirrors common ROS 2 workflows:

csyn topic list
csyn topic echo synapse/manual_control
csyn topic pub test/topic --text hello
csyn topic hz synapse/manual_control
csyn topic bw synapse/manual_control

csyn type list
csyn type show ManualControl

csyn bag record 'synapse/**' -o flight.csynbag
csyn bag info flight.csynbag
csyn bag play flight.csynbag
csyn bag export flight.csynbag -o flight.jsonl

csyn graph serve

The default Zenoh router endpoint is tcp/127.0.0.1:7447. Override it with:

csyn --connect tcp/192.168.1.10:7447 topic list
CSYN_CONNECT=tcp/192.168.1.10:7447 csyn topic list

If no router is running locally, start one in another terminal:

zenohd -l tcp/127.0.0.1:7447

Topic Commands

topic list subscribes to ** for a short observation window and prints topics that were seen. Zenoh does not provide ROS-style graph discovery by default, so this is traffic-observed discovery for now.

topic echo decodes known Synapse FlatBuffers payloads using synapse_fbs when the topic name or --type identifies the root type:

csyn topic echo synapse/manual_control
csyn topic echo synapse/manual_control --type ManualControl --output json
csyn topic echo test/topic --raw

topic pub currently publishes raw payloads from text or files:

csyn topic pub test/topic --text hello
csyn topic pub test/topic --file payload.bin
csyn topic pub test/topic --text hello --rate 10 --count 100

Typed JSON-to-FlatBuffer publish is intentionally left for the BFBS reflection builder layer.

Graph Debugger

graph serve starts a local web UI for debugging traffic and Zenoh topology:

csyn graph serve
csyn --connect tcp/127.0.0.1:7448 graph serve --bind 127.0.0.1:8088

Open http://127.0.0.1:8088 in a browser. The graph shows observed topics, message counts, rates, payload sizes, Zenoh router/session topology, and any publisher/subscriber declarations exposed by Zenoh admin-space.

The topic/message view is traffic-observed. App-level publisher and subscriber identity depends on what Zenoh admin-space exposes, so instrumented processes can make this richer over time without changing the graph API.

Bag Format

.csynbag v1 is a compact binary stream:

CSYNBAG1\n
u32_le record_len
synapse.log.LogRecord bytes
u32_le record_len
synapse.log.LogRecord bytes
...

Each record is a FlatBuffer synapse.log.LogRecord using the existing synapse_fbs::log schema:

LogFileHeader
SchemaRecord
TopicRecord
LogFrame

SchemaRecord carries bundled synapse_all.bfbs bytes for known root types, so recorded bags are self-describing enough for future dynamic decoders/exporters. TopicRecord maps Zenoh topic names to schema IDs. LogFrame stores the compact per-sample payload with a monotonic timestamp and numeric topic ID.

The v1 stream is simple and append-friendly. A later v2 can keep the same logical records but group frames into compressed chunks with an index footer.

Built-In Types

The current decoder registry includes these synapse_fbs root types:

csyn type list

The registry is intentionally centralized in src/types.rs, so adding a new generated FlatBuffers root is a local change.