refactor/serializing (#1)

Co-authored-by: matst80 <mats.tornberg@gmail.com>
Reviewed-on: https://git.tornberg.me/mats/go-cart-actor/pulls/1

rpc-pool.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"io"
+	"net"
+	"strings"
+)
+
+type RemoteGrainPool struct {
+	Hosts  []string
+	grains map[CartId]RemoteGrain
+}
+
+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 {
+	client  net.Conn
+	Id      CartId
+	Address string
+}
+
+func NewRemoteGrain(id CartId, address string) *RemoteGrain {
+	return &RemoteGrain{
+		Id:      id,
+		Address: address,
+	}
+}
+
+func (g *RemoteGrain) Connect() error {
+	if g.client == nil {
+		client, err := net.Dial("tcp", g.Address)
+		if err != nil {
+			return err
+		}
+		g.client = client
+	}
+	return nil
+}
+
+func (g *RemoteGrain) HandleMessage(message *Message, isReplay bool) ([]byte, error) {
+
+	err := SendCartPacket(g.client, g.Id, RemoteHandleMessage, message.Write)
+	if err != nil {
+		return nil, err
+	}
+	_, data, err := ReceivePacket(g.client)
+	return data, err
+}
+
+func (g *RemoteGrain) GetId() CartId {
+	return g.Id
+}
+
+func (g *RemoteGrain) GetCurrentState() ([]byte, error) {
+
+	err := SendCartPacket(g.client, g.Id, RemoteGetState, func(w io.Writer) error {
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	_, data, err := ReceivePacket(g.client)
+	return data, err
+}
+
+func NewRemoteGrainPool(addr ...string) *RemoteGrainPool {
+	return &RemoteGrainPool{
+		Hosts:  addr,
+		grains: make(map[CartId]RemoteGrain),
+	}
+}
+
+func (p *RemoteGrainPool) findRemoteGrain(id CartId) *RemoteGrain {
+	grain, ok := p.grains[id]
+	if !ok {
+		return nil
+	}
+	return &grain
+}
+
+func (p *RemoteGrainPool) Process(id CartId, messages ...Message) ([]byte, error) {
+	var result []byte
+	var err error
+	grain := p.findRemoteGrain(id)
+	if grain == nil {
+		grain = NewRemoteGrain(id, p.Hosts[0])
+		grain.Connect()
+		p.grains[id] = *grain
+	}
+	for _, message := range messages {
+		result, err = grain.HandleMessage(&message, false)
+	}
+	return result, err
+}
+
+func (p *RemoteGrainPool) Get(id CartId) ([]byte, error) {
+	grain := p.findRemoteGrain(id)
+	if grain == nil {
+		return nil, nil
+	}
+	return grain.GetCurrentState()
+}