fix(ops): bound indexed log host length

Co-authored-by: multica-agent <github@multica.ai>

backend/internal/service/ops_system_log_sink.go

@@ -46,15 +46,14 @@ type OpsSystemLogSink struct {
 	lastError atomic.Value
 }
 
+const maxSystemLogHostLength = 255
+
 func NewOpsSystemLogSink(opsRepo OpsRepository) *OpsSystemLogSink {
 	ctx, cancel := context.WithCancel(context.Background())
-	host, err := os.Hostname()
-	if err != nil || strings.TrimSpace(host) == "" {
-		host = "unknown"
-	}
+	rawHost, err := os.Hostname()
 	s := &OpsSystemLogSink{
 		opsRepo:       opsRepo,
-		host:          strings.TrimSpace(host),
+		host:          normalizeSystemLogHost(rawHost, err),
 		queue:         make(chan *logger.LogEvent, 5000),
 		batchSize:     200,
 		flushInterval: time.Second,
@@ -65,6 +64,18 @@ func NewOpsSystemLogSink(opsRepo OpsRepository) *OpsSystemLogSink {
 	return s
 }
 
+func normalizeSystemLogHost(host string, err error) string {
+	host = strings.TrimSpace(host)
+	if err != nil || host == "" {
+		return "unknown"
+	}
+	runes := []rune(host)
+	if len(runes) > maxSystemLogHostLength {
+		return string(runes[:maxSystemLogHostLength])
+	}
+	return host
+}
+
 func (s *OpsSystemLogSink) Start() {
 	if s == nil || s.opsRepo == nil {
 		return

backend/internal/service/ops_system_log_sink_test.go

@@ -328,3 +328,20 @@ func TestOpsSystemLogSink_HelperFunctions(t *testing.T) {
 		}
 	}
 }
+
+func TestNormalizeSystemLogHost(t *testing.T) {
+	if got := normalizeSystemLogHost(" api-node-1 ", nil); got != "api-node-1" {
+		t.Fatalf("trimmed host = %q, want api-node-1", got)
+	}
+	if got := normalizeSystemLogHost("", nil); got != "unknown" {
+		t.Fatalf("empty host = %q, want unknown", got)
+	}
+	if got := normalizeSystemLogHost("api-node-1", errors.New("hostname unavailable")); got != "unknown" {
+		t.Fatalf("errored host = %q, want unknown", got)
+	}
+	longHost := strings.Repeat("节", maxSystemLogHostLength+1)
+	got := normalizeSystemLogHost(longHost, nil)
+	if runeCount := len([]rune(got)); runeCount != maxSystemLogHostLength {
+		t.Fatalf("truncated host rune count = %d, want %d", runeCount, maxSystemLogHostLength)
+	}
+}