rework list courses page to be flatten

internal/common/config/trace.go

@@ -1,6 +1,38 @@
 package config
 
-type Trace struct {
-	Endpoint   string `json:"endpoint"`
-	LicenseKey string `json:"license_key"`
+import "errors"
+
+type TraceClientType uint8
+
+const (
+	TraceClientTypeUnset TraceClientType = iota
+	TraceClientTypeHTTP
+	TraceClientTypeGRPC
+	TraceClientTypeStdout
+)
+
+func (t *TraceClientType) UnmarshalText(data []byte) error {
+	dataStr := string(data)
+	switch dataStr {
+	case "http":
+		*t = TraceClientTypeHTTP
+	case "grpc":
+		*t = TraceClientTypeGRPC
+	case "stdout":
+		*t = TraceClientTypeStdout
+	case "":
+	default:
+		return errors.New("unsupported value " + dataStr)
+	}
+
+	return nil
+}
+
+type Trace struct {
+	Endpoint  string          `json:"endpoint"`
+	APIKey    string          `json:"api_key"`
+	APIHeader string          `json:"api_header"`
+	Type      TraceClientType `json:"type"`
+
+	ShowMetrics bool `json:"show_metrics"`
 }