/*
 *
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

package main

import (
	"flag"
	"fmt"
	"io"

	"golang.org/x/net/context"
	"google.golang.org/grpc"
	"google.golang.org/grpc/grpclog"
	metricspb "google.golang.org/grpc/stress/grpc_testing"
)

var (
	metricsServerAddress = flag.String("metrics_server_address", "", "The metrics server addresses in the fomrat <hostname>:<port>")
	totalOnly            = flag.Bool("total_only", false, "If true, this prints only the total value of all gauges")
)

func printMetrics(client metricspb.MetricsServiceClient, totalOnly bool) {
	stream, err := client.GetAllGauges(context.Background(), &metricspb.EmptyMessage{})
	if err != nil {
		grpclog.Fatalf("failed to call GetAllGuages: %v", err)
	}

	var (
		overallQPS int64
		rpcStatus  error
	)
	for {
		gaugeResponse, err := stream.Recv()
		if err != nil {
			rpcStatus = err
			break
		}
		if _, ok := gaugeResponse.GetValue().(*metricspb.GaugeResponse_LongValue); !ok {
			panic(fmt.Sprintf("gauge %s is not a long value", gaugeResponse.Name))
		}
		v := gaugeResponse.GetLongValue()
		if !totalOnly {
			grpclog.Printf("%s: %d", gaugeResponse.Name, v)
		}
		overallQPS += v
	}
	if rpcStatus != io.EOF {
		grpclog.Fatalf("failed to finish server streaming: %v", rpcStatus)
	}
	grpclog.Printf("overall qps: %d", overallQPS)
}

func main() {
	flag.Parse()
	if *metricsServerAddress == "" {
		grpclog.Fatalf("Metrics server address is empty.")
	}

	conn, err := grpc.Dial(*metricsServerAddress, grpc.WithInsecure())
	if err != nil {
		grpclog.Fatalf("cannot connect to metrics server: %v", err)
	}
	defer conn.Close()

	c := metricspb.NewMetricsServiceClient(conn)
	printMetrics(c, *totalOnly)
}