The server ran os.Exit at the end of its own goroutine, which raced fx's
teardown and could kill the process before reportbuf's OnStop flushed the
buffer — losing up to a full flush window of telemetry on every restart,
silently and with exit 0. The server now requests shutdown through
fx.Shutdowner, so fx runs every OnStop in dependency order.
The http.Server is built synchronously in OnStart before the serving
goroutine starts, so shutdown can no longer race or nil-deref it; the
field is never written and read from two goroutines without a
happens-before edge. A listen failure now exits non-zero via
fx.ExitCode(1). reportbuf's OnStop is guarded by sync.Once. writeTimeout
now exceeds the chi per-request budget, with a comment, so that budget is
reachable. Dead startupTime, exitCode, and cancelFunc fields are gone.
A new test buffers a report and asserts it reaches disk after the fx
lifecycle stops.
Model: opus-4-8
Introduce the Go backend (netwatch-server) with an HTTP API that
accepts telemetry reports and persists them as zstd-compressed JSONL
files. Reports are buffered in memory and flushed to disk when the
buffer reaches 10 MiB or every 60 seconds.
sneak