-DEFINE_string(server_address, "", "channelz server address");
-DEFINE_string(custom_credentials_type, "", "custom credentials type");
-DEFINE_int64(sampling_times, 1, "number of sampling");
-DEFINE_int64(sampling_interval_seconds, 0, "sampling interval in seconds");
-DEFINE_string(output_json, "", "output filename in json format");
+ABSL_FLAG(std::string, server_address, "", "channelz server address");
+ABSL_FLAG(std::string, custom_credentials_type, "", "custom credentials type");
+ABSL_FLAG(int64_t, sampling_times, 1, "number of sampling");
+// TODO(Capstan): Consider using absl::Duration
+ABSL_FLAG(int64_t, sampling_interval_seconds, 0,
+ "sampling interval in seconds");
+ABSL_FLAG(std::string, output_json, "", "output filename in json format");