fix: Don't include non exported fields or ignored types in JSON schema (#1824)

#### Summary

Noticed this while opening cloudquery/cloudquery-issues#2116.


---

Author: erezrokah

transformers/struct.go

@@ -277,11 +277,15 @@ func (t *structTransformer) fieldToJSONSchema(field reflect.StructField, depth i
 		fieldsMap := make(map[string]any)
 		fieldType := normalizedField.Elem().Type()
 		for i := 0; i < fieldType.NumField(); i++ {
-			name, err := t.nameTransformer(fieldType.Field(i))
+			structField := fieldType.Field(i)
+			if !structField.IsExported() || isTypeIgnored(structField.Type) {
+				continue
+			}
+			name, err := t.nameTransformer(structField)
 			if err != nil {
 				continue
 			}
-			columnType, err := t.getColumnType(fieldType.Field(i))
+			columnType, err := t.getColumnType(structField)
 			if err != nil {
 				continue
 			}
@@ -291,7 +295,7 @@ func (t *structTransformer) fieldToJSONSchema(field reflect.StructField, depth i
 			}
 			// Avoid infinite recursion
 			if columnType == types.ExtensionTypes.JSON && depth < maxJSONTypeSchemaDepth {
-				fieldsMap[name] = t.fieldToJSONSchema(fieldType.Field(i), depth+1)
+				fieldsMap[name] = t.fieldToJSONSchema(structField, depth+1)
 				continue
 			}
 			asList, ok := columnType.(*arrow.ListType)

transformers/struct_test.go

@@ -6,6 +6,7 @@ import (
 	"slices"
 	"testing"
 	"time"
+	"unsafe"
 
 	"github.com/apache/arrow/go/v17/arrow"
 	"github.com/cloudquery/plugin-sdk/v4/schema"
@@ -624,6 +625,21 @@ func TestJSONTypeSchema(t *testing.T) {
 				"level0": `{"level1":{"level2":{"level3":{"level4":{"level5":"json"}}}}}`,
 			},
 		},
+		{
+			name: "ignores non exported and ignored types",
+			testStruct: struct {
+				Item struct {
+					nonExported   string
+					f             func()
+					c             chan int
+					unsafePointer unsafe.Pointer
+					Exported      string `json:"exported"`
+				} `json:"item"`
+			}{},
+			want: map[string]string{
+				"item": `{"exported":"utf8"}`,
+			},
+		},
 	}
 
 	for _, tt := range tests {