Create scaffolding of ddl-simulator

Implement global server as control plane

Implement device to get their info from global server and connect each
others

pkg/global/global.go

@@ -0,0 +1,92 @@
+package global
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+
+	pb "git.pengzhan.dev/ddp-simulator/proto"
+	log "github.com/sirupsen/logrus"
+	"google.golang.org/protobuf/proto"
+)
+
+type GlobalServer struct {
+	pb.UnimplementedGlobalServiceServer
+
+	Configs map[string]config
+}
+
+type config struct {
+	ID         string  `json:"id"`
+	Role       string  `json:"role"`
+	Capacity   float32 `json:"capacity"`
+	IP         string  `json:"ip"`
+	Port       int     `json:"port"`
+	ParentID   string  `json:"parentID"`
+	ParentIP   string  `json:"parentIP"`
+	ParentPort int     `json:"parentPort"`
+}
+
+func NewGlobalServer(configPath string) *GlobalServer {
+	configs, err := ReadConfigFromPath(configPath)
+	if err != nil {
+		log.Fatalf("could not read config file: %v", err)
+	}
+	return &GlobalServer{
+		Configs: configs,
+	}
+}
+
+func ReadConfigFromPath(configPath string) (map[string]config, error) {
+	file, err := os.Open(configPath)
+	if err != nil {
+		return nil, fmt.Errorf("could not open file: %v", err)
+	}
+	defer file.Close()
+
+	fileContent, err := io.ReadAll(file)
+	if err != nil {
+		return nil, fmt.Errorf("could not read file content: %v", err)
+	}
+
+	var configs []config
+	err = json.Unmarshal(fileContent, &configs)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse JSON content: %v", err)
+	}
+
+	configMap := make(map[string]config)
+
+	for _, c := range configs {
+		configMap[c.ID] = c
+	}
+
+	return configMap, nil
+}
+
+func (g *GlobalServer) Init(ctx context.Context, in *pb.InitRequest) (*pb.InitResponse, error) {
+	config, ok := g.Configs[in.Id]
+	if !ok {
+		log.Errorf("device %s not found", in.Id)
+		return nil, fmt.Errorf("device %s not found", in.Id)
+	}
+	log.Infof("device %s init", config.ID)
+	
+	resp := &pb.InitResponse{
+		Role:     config.Role,
+		Capacity: proto.Float32(config.Capacity),
+		Ip:       config.IP,
+		Port:     int32(config.Port),
+	}
+	if config.ParentID != "" {
+		resp.ParentId = proto.String(config.ParentID)
+		resp.Pip = proto.String(config.ParentIP)
+		resp.Pport = proto.Int32(int32(config.ParentPort))
+	}
+	if config.Capacity != 0 {
+		resp.Capacity = proto.Float32(config.Capacity)
+	}
+	return resp, nil
+}