Power: say why a BMC command failed (CLI, UI); certificate changes are events

Found in the lab test of certificate pinning: the CLI printed only
'ipmitool failed on 1 machine(s)'.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/rollcall/client.go

@@ -232,13 +232,16 @@ func runClient(cmd string, args []string) error {
 			if len(ids) > 1 {
 				fmt.Printf("%s: ", id)
 			}
-			fmt.Println(str(d["output"]))
+			if o := str(d["output"]); o != "" {
+				fmt.Println(o)
+			}
 			if ok, _ := d["ok"].(bool); !ok {
+				fmt.Println("error:", orDefault(str(d["error"]), "the BMC command failed"))
 				failed++
 			}
 		}
 		if failed > 0 {
-			return fmt.Errorf("ipmitool failed on %d machine(s)", failed)
+			return fmt.Errorf("power %s failed on %d machine(s)", args[1], failed)
 		}
 	case "bootdev":
 		_ = need(2)

cmd/rollcall/ipmi.go

@@ -72,7 +72,16 @@ func (a *App) power(ctx context.Context, m *Machine, op, arg string) (string, er
 	if c, err = a.pinBMC(ctx, m, c); err != nil {
 		return "", err
 	}
-	return a.powerVia(ctx, a.rackOf(m), c, op, arg)
+	out, err := a.powerVia(ctx, a.rackOf(m), c, op, arg)
+	a.noteCertChange(ctx, m, err)
+	return out, err
+}
+
+// noteCertChange puts a refused BMC certificate on the machine's events.
+func (a *App) noteCertChange(ctx context.Context, m *Machine, err error) {
+	if err != nil && strings.Contains(err.Error(), "certificate changed") {
+		_ = a.store.AddEvent(ctx, m.ID, "bmc certificate changed", oneLine(err.Error()))
+	}
 }
 
 // pinBMC records the certificate of an HTTPS BMC (Redfish, Proxmox) before

cmd/rollcall/server.go

@@ -786,7 +786,11 @@ func (a *App) handlePower(w http.ResponseWriter, r *http.Request) {
 	if action != "status" {
 		_ = a.store.AddEvent(r.Context(), m.ID, "power "+action, out)
 	}
-	writeJSON(w, 200, obj{"id": m.ID, "action": action, "ok": err == nil, "output": out})
+	res := obj{"id": m.ID, "action": action, "ok": err == nil, "output": out}
+	if err != nil {
+		res["error"] = err.Error()
+	}
+	writeJSON(w, 200, res)
 }
 
 func (a *App) handleBootdev(w http.ResponseWriter, r *http.Request) {

cmd/rollcall/web/app.js

@@ -355,7 +355,7 @@ async function each(ids, label, fn) {
   await refresh(true);
 }
 const act = {
-  power: (ids, action) => each(ids, `power ${action}`, async id => { const r = await api('POST', `/api/v1/machines/${id}/power`, { action }); return r.output || (r.ok ? 'ok' : 'failed'); }),
+  power: (ids, action) => each(ids, `power ${action}`, async id => { const r = await api('POST', `/api/v1/machines/${id}/power`, { action }); if (!r.ok) throw new Error(r.error || r.output || 'the BMC command failed'); return r.output || 'ok'; }),
   bootdev: (ids, device) => each(ids, `bootdev ${device}`, async id => { const r = await api('POST', `/api/v1/machines/${id}/bootdev`, { device }); return r.output || (r.ok ? 'ok' : 'failed'); }),
   async deploy(ids) {
     const one = ids.length === 1 ? S.machines.find(m => m.id === ids[0]) : null;