Development Update — May 4

Skywire: Transport Uptime — CXO-Driven Heartbeats

PR #2426 rewrites the transport uptime model from polled re-registration to event-driven heartbeats with slot-accurate timelines.

Pre-fix: TPD inferred uptime from the timing of register/deregister and the 90-second TTL refresh. A transport that was up but lost its refresh window (slow network, brief TPD outage) showed up as “down” until the next refresh succeeded. The bitmap timeline had 90-second resolution and lots of false negatives.

Post-fix: every visor publishes per-transport heartbeats into a CXO feed on a fixed slot cadence (1-minute slots, 1440 per day). The aggregator merges the published bitmaps from both edges of each transport — a transport counts as “up” in a slot iff both edges’ bitmaps mark it up. Self-edge heartbeats can’t lie alone; the merge requires agreement.

The visible artifact is cli rewards uptime and the hypervisor’s uptime tab now show minute-granularity timelines with the same accuracy as the underlying heartbeat record, instead of a 90s-quantized approximation.

Skywire: Retire On-Disk CSV Transport Log

2427 transport+visor: retire on-disk CSV transport-log store; serve history from stats bbolt — the legacy ~/.skywire/local/transport_log/<date>.csv files were never read by anything that wasn’t a debugging script. They piled up at ~50KB/day per visor and only operators with shell access could grep them.

The bbolt-backed stats store (added with the latency PR earlier) is the new home: same content, structured access, served via the visor’s RPC API to the hypervisor and CLI. The CSV writer is removed; the directory and existing files are left in place for any operator with a pipeline already reading them.

Skywire: Per-Service Self-Uptime + Version Provenance

2428 serviceuptime: per-service self-uptime + version provenance via local bbolt — every long-running service (visor, dmsg-server, dmsg-discovery, ar, rf, sd, tpd, ut) now writes its own start/stop transitions into a tiny per-service bbolt at the service’s data dir. The schema captures:

• Start timestamp + version string at start
• Clean shutdown timestamps (SIGTERM path)
• Crash detection (no clean-shutdown record between starts)

The hypervisor reads each service’s local store via the existing RPC channel and displays it on the fleet-resources tab. Operators get a per-service uptime + version history without scraping logs.

Skywire: TPD Perf

Two perf PRs hit TPD’s hot paths:

2429 perf(tpd): bulk-read uptime timeline bitmaps with one GET per day — the per-PK timeline query was issuing ~30 Redis GETs (one per day for a 30-day window). The replacement issues one GET per day across all PKs in the query (an MGET batched by day), cutting Redis round-trips by the number of PKs queried.

2430 perf(tpd): no-latency variant for mirrorEdges + concat redis-key builders — MirrorEdges had a single code path that always touched the latency field; mirror calls from the cache-invalidation hot path don’t need it. The split saves a Redis HGET per call. Also concatenates Redis-key strings with strings.Builder instead of fmt.Sprintf — a small win that adds up at the call rate.

Skywire: TPD Latency Cap

2425 transport-discovery: cap UpdateLatency at MaxReasonableRTTMs — RTT measurements over 30 seconds are almost certainly a stuck measurement loop (peer asleep, transport down between handshakes). Latency > 30s now caps at 30s rather than poisoning the rolling average. The 30s threshold is the same one the transport-level ping uses to declare a transport unreachable, so the two thresholds align.

Skywire: Misc

• 2431 visor: wire --pprofmode through dmsg cmdutil so non-http pprof modes work end-to-end (the flag was being silently dropped when the visor’s pprof was reachable via dmsg only).
• 2432 nix: derive source-build version from flake git metadata + fix the readme flake input. Nix builds from a checkout get the right version string in --version output.
• 2424 hvui/cxo metrics + fleet resources — hypervisor UI surfaces the new CXO publisher/subscriber counters alongside fleet-wide resource graphs.