Transport & QoS¶
Socket settings¶
| Socket | Option | Value | Notes |
|---|---|---|---|
| Publisher PUB | SNDHWM |
10 (default queue_size) |
Drops under backpressure |
| Publisher PUB | LINGER |
0 | Immediate close |
| Subscriber SUB | RCVHWM |
10 | Oldest messages evicted when full |
| Subscriber SUB | LINGER |
0 | |
| Daemon REP | RCVTIMEO |
1000 ms | Keeps Ctrl-C responsive |
| Daemon REP | LINGER |
0 |
Delivery semantics¶
- Publisher uses
zmq.NOBLOCK: if the send queue is full, the message is silently dropped. - Subscriber HWM is a ring buffer: oldest messages are silently evicted on overflow.
Fine for best-effort telemetry. Not safe for control commands without an application-level ack — the bytes can be lost on either side.