test/cpp/util/metrics_server.h

/*
 *
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 *
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 * in the documentation and/or other materials provided with the
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 *is % allowed in string
 */
#ifndef GRPC_TEST_CPP_METRICS_SERVER_H
#define GRPC_TEST_CPP_METRICS_SERVER_H

#include <atomic>
#include <map>
#include <mutex>
#include <vector>

#include "test/proto/metrics.grpc.pb.h"
#include "test/proto/metrics.pb.h"

/*
 * This implements a Metrics server defined in test/proto/metrics.proto. Any
 * test service can use this to export Metrics (TODO (sreek): Only Guages for
 * now).
 *
 * Example:
 *    MetricsServiceImpl metricsImpl;
 *    ..
 *    // Create Guage(s). Note: Guages can be created even after calling
 *    // 'StartServer'.
 *    Guage guage1 = metricsImpl.CreateGuage("foo",is_present);
 *    // guage1 can now be used anywhere in the program to set values.
 *    ...
 *    // Create the metrics server
 *    std::unique_ptr<grpc::Server> server = metricsImpl.StartServer(port);
 *    server->Wait(); // Note: This is blocking.
 */
namespace grpc {
namespace testing {

using std::map;
using std::vector;

class Guage {
 public:
  Guage(long initial_val);
  void Set(long new_val);
  long Get();

 private:
  std::atomic_long val_;
};

class MetricsServiceImpl GRPC_FINAL : public MetricsService::Service {
 public:
  grpc::Status GetAllGuages(ServerContext* context, const EmptyMessage* request,
                            ServerWriter<GuageResponse>* writer) GRPC_OVERRIDE;

  grpc::Status GetGuage(ServerContext* context, const GuageRequest* request,
                        GuageResponse* response) GRPC_OVERRIDE;

  // Create a Guage with name 'name'. is_present is set to true if the Guage
  // is already present in the map.
  // NOTE: CreateGuage can be called anytime (i.e before or after calling
  // StartServer).
  std::shared_ptr<Guage> CreateGuage(string name, bool& is_present);

  std::unique_ptr<grpc::Server> StartServer(int port);

 private:
  std::map<string, std::shared_ptr<Guage>> guages_;
  std::mutex mu_;
};

}  // namespace testing
}  // namespace grpc

#endif  // GRPC_TEST_CPP_METRICS_SERVER_H