add DumpPrometheusMetricsToIOBuf

src/brpc/builtin/prometheus_metrics_service.cpp

@@ -22,6 +22,7 @@
 #include "brpc/closure_guard.h"             // ClosureGuard
 #include "brpc/builtin/prometheus_metrics_service.h"
 #include "brpc/builtin/common.h"
+#include "brpc/details/server_private_accessor.h"
 #include "bvar/bvar.h"
 
 namespace bvar {
@@ -181,14 +182,21 @@ void PrometheusMetricsService::default_method(::google::protobuf::RpcController*
     ClosureGuard done_guard(done);
     Controller *cntl = static_cast<Controller*>(cntl_base);
     cntl->http_response().set_content_type("text/plain");
+    if (DumpPrometheusMetricsToIOBuf(_server, &cntl->response_attachment()) != 0) {
+        cntl->SetFailed("Fail to dump metrics");
+        return;
+    }
+}
+
+int DumpPrometheusMetricsToIOBuf(const Server* server, butil::IOBuf* output) {
     butil::IOBufBuilder os;
-    PrometheusMetricsDumper dumper(&os, _server->ServerPrefix());
+    PrometheusMetricsDumper dumper(&os, brpc::ServerPrivateAccessor(server).ServerPrefix());
     const int ndump = bvar::Variable::dump_exposed(&dumper, NULL);
     if (ndump < 0) {
-        cntl->SetFailed("Fail to dump metrics");
-        return;
+        return -1;
     }
-    os.move_to(cntl->response_attachment());
+    os.move_to(*output);
+    return 0;
 }
 
 } // namespace brpc

src/brpc/builtin/prometheus_metrics_service.h

@@ -31,10 +31,13 @@ public:
                         const ::brpc::MetricsRequest* request,
                         ::brpc::MetricsResponse* response,
                         ::google::protobuf::Closure* done) override;
+
 private:
     Server* _server;
 };
 
+int DumpPrometheusMetricsToIOBuf(const Server* server, butil::IOBuf* output);
+
 } // namepace brpc
 
 #endif  // BRPC_PROMETHEUS_METRICS_SERVICE_H

src/brpc/details/server_private_accessor.h

@@ -97,6 +97,8 @@ public:
 
     RestfulMap* global_restful_map() const
     { return _server->_global_restful_map; }
+
+    std::string ServerPrefix() const { return _server->ServerPrefix(); }
     
 private:
     const Server* _server;