go-cli-demo-stale-url-listen-addr

Answer

Bug 1 — stale hardcoded URL. The demo command printed a literal http://localhost:8080/dashboard while the server actually binds cfg.ListenAddr (default <ip-address>:9734, overridable via RABBITHOLE_LISTEN_ADDR). The fix derives the hint from the same value the listener uses, via net.SplitHostPort, substituting the wildcard <ip-address> (and IPv6 ::/empty host) with localhost so the printed link is reachable from the user's machine:

// before
fmt.Printf("Open http://localhost:8080/dashboard to see your traces.\n")

// after
func DashboardURL(listenAddr string) string {
    host, port, err := net.SplitHostPort(listenAddr)
    if err != nil {
        if strings.HasPrefix(listenAddr, ":") {
            return "http://localhost" + listenAddr + DashboardPath
        }
        return "http://" + listenAddr + DashboardPath // best-effort fallback
    }
    if host == "<ip-address>" || host == "::" || host == "" {
        host = "localhost"
    }
    return "http://" + net.JoinHostPort(host, port) + DashboardPath
}
// used as: fmt.Printf("Demo complete. Open %s ...\n", DashboardURL(cfg.ListenAddr))

Bug 2 — session finalized before child rows → FK failure. StoreTraces resolves the owning session_id via agent_pid + status='running'. The demo stored the session as completed first, so on a fresh DB the lookup found nothing and the trace insert hit a foreign-key violation — the hint could never print. Fix: create the session as running, write child rows, then finalize:

// before
sessionID, _ := st.CreateSession(ctx, pid, "completed") // resolved nothing
st.StoreTraces(ctx, pid, traces)                        // FK violation on fresh DB
fmt.Println("Open http://localhost:8080/dashboard ...") // never reached

// after
sessionID, err := st.CreateSession(ctx, pid, "running")  // 1. running first
if err != nil { return err }
if err := st.StoreTraces(ctx, pid, traces); err != nil { // 2. child rows resolve session_id
    return err
}
if err := st.UpdateSessionStatus(ctx, sessionID, "completed"); err != nil { // 3. finalize
    return err
}
fmt.Printf("Demo complete. Open %s to see your traces.\n", DashboardURL(cfg.ListenAddr))

The same DashboardURL value also feeds the server startup banner (listening on X (dashboard: Y)), keeping the two in lockstep.