SSE /global/event heartbeat floods shared opencode.log at INFO level — 816M lines / 95 GB over 34 days of uptime

Environment

• OpenCode 1.18.27, Linux (Ubuntu 24.04)
• Long-lived server started from source: bun --conditions=browser ./src/index.ts serve --hostname 127.0.0.1 --port 4096 (uptime 34 days)
• Log: ~/.local/share/opencode/log/opencode.log (shared by all opencode processes on the machine)

What happened

A single long-lived opencode serve (Bun) process wrote ~816,883,425 "global event heartbeat" INFO lines into the shared log file over 34 days of uptime, reaching 95,764,439,991 bytes (~95 GB) on disk.

Evidence from the log itself:

816883425  # rg -c "global event heartbeat" — total matching lines
5127 run=77869d9c  # heartbeats in a 50-second window, all one run ID
connectedForMs=2936121857  # ≈ 34 days — matches the process uptime exactly

All heartbeats came from one run= ID. The values of connectedForMs spanned a ~6-hour range (many concurrent SSE subscribers of different ages, each logging its own heartbeat).

Impact

• 95 GB of disk consumed by keep-alive noise in a single append-only file.
• The log is shared: every opencode process on the machine holds it open, so one wedged/long-lived subscriber floods the log for everyone and makes real errors nearly impossible to find (816M junk lines).
• After killing the 34-day-old process, the heartbeat spam stopped completely (1 line / 10s → 0). Fresh servers produce only a couple of heartbeat lines per minute. So the flood is per-connection accumulation over long uptime, not a steady-state rate.

Expected behavior

• SSE keep-alive/heartbeat events should not be logged at INFO level (ideally not logged at all, or only at trace/debug level).
• The shared log file should either rotate or have a size cap, so a single pathological subscriber cannot fill the disk.

Repro

1. Start opencode serve.
2. Keep one or more SSE /global/event subscribers connected for days.
3. Watch ~/.local/share/opencode/log/opencode.log grow unboundedly with "global event heartbeat" lines at a rate proportional to the number and age of open connections.