implement statuscode in packets

remote-grain.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+func (id CartId) String() string {
+	return strings.Trim(string(id[:]), "\x00")
+}
+
+func ToCartId(id string) CartId {
+	var result [16]byte
+	copy(result[:], []byte(id))
+	return result
+}
+
+type RemoteGrain struct {
+	*CartClient
+	Id   CartId
+	Host string
+}
+
+func NewRemoteGrain(id CartId, host string) (*RemoteGrain, error) {
+	client, err := CartDial(fmt.Sprintf("%s:1337", host))
+	if err != nil {
+		return nil, err
+	}
+
+	return &RemoteGrain{
+		Id:         id,
+		Host:       host,
+		CartClient: client,
+	}, nil
+}
+
+var (
+	remoteCartLatency = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "cart_remote_grain_calls_total_latency",
+		Help: "The total latency of remote grains",
+	})
+	remoteCartCallsTotal = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "cart_remote_grain_calls_total",
+		Help: "The total number of calls to remote grains",
+	})
+)
+
+var start time.Time
+
+func MeasureLatency(fn func() (*CallResult, error)) (*CallResult, error) {
+	start = time.Now()
+	data, err := fn()
+	if err != nil {
+		return data, err
+	}
+	elapsed := time.Since(start).Milliseconds()
+	go func() {
+		remoteCartLatency.Add(float64(elapsed))
+		remoteCartCallsTotal.Inc()
+	}()
+	return data, nil
+}
+
+func (g *RemoteGrain) HandleMessage(message *Message, isReplay bool) (*CallResult, error) {
+
+	data, err := GetData(message.Write)
+	if err != nil {
+		return nil, err
+	}
+	reply, err := MeasureLatency(func() (*CallResult, error) {
+		return g.Call(RemoteHandleMutation, g.Id, RemoteHandleMutationReply, data)
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return reply, err
+}
+
+func (g *RemoteGrain) GetId() CartId {
+	return g.Id
+}
+
+func (g *RemoteGrain) GetCurrentState() (*CallResult, error) {
+	return MeasureLatency(func() (*CallResult, error) { return g.Call(RemoteGetState, g.Id, RemoteGetStateReply, []byte{}) })
+}