server.go

package instruments

import (
	"encoding/json"
	"fmt"
	"net/http"

	"code.cloudfoundry.org/lager"
	"github.com/cloudfoundry-incubator/etcd-metrics-server/instrumentation"
)

type Server struct {
	statsEndpoint string
	logger        lager.Logger
	getter        getter
}

type getter interface {
	Get(address string) (*http.Response, error)
}

func NewServer(getter getter, etcdAddr string, logger lager.Logger) *Server {
	return &Server{
		statsEndpoint: fmt.Sprintf("%s/v2/stats/self", etcdAddr),

		logger: logger,
		getter: getter,
	}
}

func (server *Server) Emit() instrumentation.Context {
	context := instrumentation.Context{
		Name: "server",
	}

	var stats RaftServerStats

	resp, err := server.getter.Get(server.statsEndpoint)
	if err != nil {
		server.logger.Error("failed-to-collect-self-stats", err)
		return context
	}

	defer resp.Body.Close()

	err = json.NewDecoder(resp.Body).Decode(&stats)
	if err != nil {
		server.logger.Error("failed-to-unmarshal-self-stats", err)
		return context
	}

	isLeader := 0
	if stats.State == "StateLeader" {
		isLeader = 1
	}

	context.Metrics = []instrumentation.Metric{
		{
			Name:  "IsLeader",
			Value: isLeader,
		},
		{
			Name:  "SendingBandwidthRate",
			Value: stats.SendingBandwidthRate,
		},
		{
			Name:  "ReceivingBandwidthRate",
			Value: stats.RecvingBandwidthRate,
		},
		{
			Name:  "SendingRequestRate",
			Value: stats.SendingPkgRate,
		},
		{
			Name:  "ReceivingRequestRate",
			Value: stats.RecvingPkgRate,
		},
		{
			Name:  "SentAppendRequests",
			Value: stats.SendAppendRequestCnt,
		},
		{
			Name:  "ReceivedAppendRequests",
			Value: stats.RecvAppendRequestCnt,
		},
	}

	return context
}