Do not use rb_raise to gen exception from Go

ext/ruby_snowflake.go

@@ -45,6 +45,7 @@ var rbSnowflakeModule C.VALUE
 var DB_IDENTIFIER = C.rb_intern(C.CString("db"))
 var RESULT_IDENTIFIER = C.rb_intern(C.CString("rows"))
 var RESULT_DURATION = C.rb_intern(C.CString("@query_duration"))
+var RESULT_ERROR = C.rb_intern(C.CString("@error"))
 
 var objects = make(map[interface{}]bool)
 
@@ -91,12 +92,22 @@ func (x SnowflakeClient) Fetch(statement C.VALUE) C.VALUE {
 		fmt.Println("statement", RbGoString(statement))
 	}
 	rows, err := x.db.QueryContext(sf.WithHigherPrecision(context.Background()), RbGoString(statement))
+	if err != nil {
+		result := C.rb_class_new_instance(0, &empty, rbSnowflakeResultClass)
+		errStr := fmt.Sprintf("Query error: '%s'", err.Error())
+		C.rb_ivar_set(result, RESULT_ERROR, RbString(errStr))
+		return result
+	}
+
 	duration := time.Now().Sub(t1).Seconds()
 	if LOG_LEVEL > 0 {
 		fmt.Printf("Query duration: %s\n", time.Now().Sub(t1))
 	}
 	if err != nil {
-		rb_raise(C.rb_eArgError, "Query error: '%s'", err)
+		result := C.rb_class_new_instance(0, &empty, rbSnowflakeResultClass)
+		errStr := fmt.Sprintf("Query error: '%s'", err.Error())
+		C.rb_ivar_set(result, RESULT_ERROR, RbString(errStr))
+		return result
 	}
 
 	result := C.rb_class_new_instance(0, &empty, rbSnowflakeResultClass)
@@ -156,7 +167,7 @@ func Init_ruby_snowflake_client_ext() {
 	C.rb_define_private_method(rbSnowflakeClientClass, C.CString("_connect"), (*[0]byte)(C.Connect), 7)
 	C.rb_define_method(rbSnowflakeClientClass, C.CString("inspect"), (*[0]byte)(C.Inspect), 0)
 	C.rb_define_method(rbSnowflakeClientClass, C.CString("to_s"), (*[0]byte)(C.Inspect), 0)
-	C.rb_define_method(rbSnowflakeClientClass, C.CString("fetch"), (*[0]byte)(C.ObjFetch), 1)
+	C.rb_define_method(rbSnowflakeClientClass, C.CString("_fetch"), (*[0]byte)(C.ObjFetch), 1)
 
 	if LOG_LEVEL > 0 {
 		fmt.Println("init ruby snowflake client")

lib/ruby_snowflake_client.rb

@@ -11,11 +11,21 @@ def connect(account:"", warehouse:"", database:"", schema: "", user: "", passwor
       _connect(account, warehouse, database, schema, user, password, role)
       true
     end
+
+    def fetch(sql)
+      result = _fetch(sql)
+      return result if result.valid?
+      raise(result.error)
+    end
   end
 
 
   class Result
-    attr_reader :query_duration
+    attr_reader :query_duration, :error
+
+    def valid?
+      error == nil
+    end
 
     def get_all_rows(&blk)
       GC.disable