diff --git a/src/brpc/builtin/prometheus_metrics_service.cpp b/src/brpc/builtin/prometheus_metrics_service.cpp
index d903c86248..27b89fa717 100644
--- a/src/brpc/builtin/prometheus_metrics_service.cpp
+++ b/src/brpc/builtin/prometheus_metrics_service.cpp
@@ -103,10 +103,10 @@ bool PrometheusMetricsDumper::dump(const std::string& name,
 
     auto metrics_name = GetMetricsName(name);
 
-    if(emitted_metrics.find(metrics_name.as_string()) == emitted_metrics.end()){
-        *_os<< "# HELP " << metrics_name <<'\n'
-            << "# TYPE " << metrics_name <<" gauge\n";
-            emitted_metrics.insert(metrics_name.as_string());
+    if (emitted_metrics.find(metrics_name.as_string()) == emitted_metrics.end()) {
+        *_os << "# HELP " << metrics_name << '\n'
+             << "# TYPE " << metrics_name << " gauge\n";
+        emitted_metrics.insert(metrics_name.as_string());
     }
 
     *_os << name << " " << desc << '\n';
@@ -169,7 +169,7 @@ bool PrometheusMetricsDumper::DumpLatencyRecorderSuffix(
     if (!si->IsComplete()) {
         return true;
     }
-    if(emitted_metrics.find(si->metric_name) == emitted_metrics.end()){
+    if (emitted_metrics.find(si->metric_name) == emitted_metrics.end()) {
         *_os << "# HELP " << si->metric_name << '\n'
              << "# TYPE " << si->metric_name << " summary\n";
         emitted_metrics.insert(si->metric_name);