Two genuinely-offline QR readers showed GREEN: the adapter's healthCheck was
hardcoded to { ready, "stub" } and never probed. These are PUSH devices (scan →
GET our backend, resolve by serial) with NO TCP port, so a connect probe has
nothing to hit — the stub "solved" that by lying. False-healthy is the worst
failure for a status bar.
- Optional reader IP field (monitor-ONLY; scans still resolve by serial,
operation unchanged).
- Unprivileged ICMP ping (drivers/icmp.ts): shells /bin/ping -c1, exit-0 = reply.
No native dep, no CAP_NET_RAW. docker-compose.prod.yml sets
net.ipv4.ping_group_range so it works for the non-root container user.
- healthCheck: replies → ready, no reply → offline, NO IP → degraded
("set IP to monitor") — never a false green.
Verified on hardware: readers (10.0.10.7/.8) answer ICMP on the device VLAN;
UI Test connection → "● ready — ping 10.0.10.7". Tests: reader.test.ts (4).
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
julian
dd0f6e483a