ID service (#143)

* Add examples for DB

* add the id service

Co-authored-by: Janos Dobronszki <dobronszki@gmail.com>

id/handler/id.go

@@ -0,0 +1,78 @@
+package handler
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+
+	"github.com/teris-io/shortid"
+	"github.com/google/uuid"
+	"github.com/mattheath/kala/bigflake"
+	"github.com/mattheath/kala/snowflake"
+	"github.com/micro/micro/v3/service/logger"
+	"github.com/micro/micro/v3/service/errors"
+	pb "github.com/micro/services/id/proto"
+)
+
+type Id struct {
+	Snowflake *snowflake.Snowflake
+	Bigflake  *bigflake.Bigflake
+}
+
+func New() *Id {
+	id := rand.Intn(100)
+
+	sf, err := snowflake.New(uint32(id))
+	if err != nil {
+		panic(err.Error())
+	}
+	bg, err := bigflake.New(uint64(id))
+	if err != nil {
+		panic(err.Error())
+	}
+
+	return &Id{
+		Snowflake: sf,
+		Bigflake:  bg,
+	}
+}
+
+func (id *Id) Generate(ctx context.Context, req *pb.GenerateRequest, rsp *pb.GenerateResponse) error {
+	if len(req.Type) == 0 {
+		req.Type = "uuid"
+	}
+
+	switch req.Type {
+	case "uuid":
+		rsp.Type = "uuid"
+		rsp.Id = uuid.New().String()
+	case "snowflake":
+		id, err := id.Snowflake.Mint()
+		if err != nil {
+			logger.Errorf("Failed to generate snowflake id: %v", err)
+			return errors.InternalServerError("id.generate", "failed to mint snowflake id")
+		}
+		rsp.Type = "snowflake"
+		rsp.Id = fmt.Sprintf("%v", id)
+	case "bigflake":
+		id, err := id.Bigflake.Mint()
+		if err != nil {
+			logger.Errorf("Failed to generate bigflake id: %v", err)
+			return errors.InternalServerError("id.generate", "failed to mint bigflake id")
+		}
+		rsp.Type = "bigflake"
+		rsp.Id = fmt.Sprintf("%v", id)
+	case "shortid":
+		id, err := shortid.Generate()
+		if err != nil {
+			logger.Errorf("Failed to generate shortid id: %v", err)
+			return errors.InternalServerError("id.generate", "failed to generate short id")
+		}
+		rsp.Type = "shortid"
+		rsp.Id = id
+	default:
+		return errors.BadRequest("id.generate", "unsupported id type")
+	}
+
+	return nil
+}