Install Protocol Buffers
The latest release of Protocol Buffers can be found on the release page https://github.com/protocolbuffers/protobuf/releases/tag/v3.9.1
Install Libraries
Make sure Git is installed on your machine and in your system’s PATH. Install the package to your $GOPATH with the go tool from shell:
$ go get google.golang.org/grpc
Create Proto Service
Create new folder named src. In src folder, create new folder named productservice. In productservice folder, create new folder named proto. In proto folder, create new file named product.proto as below:
syntax = "proto3";
package productservice;
service ProductService {
rpc FindAll (FindAllRequest) returns (FindAllResponse);
rpc Search(SearchRequest) returns (SearchResponse);
}
message SearchRequest {
string keyword = 1;
}
message SearchResponse {
repeated Product Products = 1;
}
message FindAllRequest {
}
message FindAllResponse {
repeated Product Products = 1;
}
message Product {
string id = 1;
string name = 2;
int32 quantity = 3;
double price = 4;
bool status = 5;
}
Generate Protocol Buffers
Select productservice folder and open it in Terminal window of Visual Studio Code. Use command line as below to generate product.pb.go file:
protoc -I ./ proto/product.proto --go_out=plugins=grpc:.
Create Handlers
In productservice folder, create new folder named handlers. In this folder, create new file named handler.go as below:
package handlers
import (
"context"
productservice "productservice/proto"
"strings"
)
type ProductServiceServer struct {
}
var products []*productservice.Product
func init() {
products = []*productservice.Product{
&productservice.Product{
Id: "p01",
Name: "tivi 1",
Price: 4.5,
Quantity: 4,
Status: true,
},
&productservice.Product{
Id: "p02",
Name: "tivi 2",
Price: 22,
Quantity: 3,
Status: false,
},
&productservice.Product{
Id: "p03",
Name: "laptop 3",
Price: 27,
Quantity: 3,
Status: true,
},
}
}
func (*ProductServiceServer) FindAll(ctx context.Context, in *productservice.FindAllRequest) (*productservice.FindAllResponse, error) {
return &productservice.FindAllResponse{Products: products}, nil
}
func (*ProductServiceServer) Search(ctx context.Context, in *productservice.SearchRequest) (*productservice.SearchResponse, error) {
var result []*productservice.Product
for _, product := range products {
if strings.Contains(product.Name, in.Keyword) {
result = append(result, product)
}
}
return &productservice.SearchResponse{Products: result}, nil
}
Create Server
In productservice folder, create new folder named server. In this folder, create new file named main.go as below:
package main
import (
"fmt"
"net"
"productservice/handlers"
productservice "productservice/proto"
"google.golang.org/grpc"
)
func main() {
lis, err := net.Listen("tcp", ":1111")
if err != nil {
fmt.Println(err)
}
defer lis.Close()
s := handlers.ProductServiceServer{}
server := grpc.NewServer()
productservice.RegisterProductServiceServer(server, &s)
if err := server.Serve(lis); err != nil {
fmt.Println(err)
}
}
Start Server
Select main.go file in server folder and open it in Terminal window of Visual Studio Code. Use command line as below to start server:
go run main.go
Create Client Interceptors
In src folder, create new folder named client. In src folder, create new folder named interceptors. In interceptors folder, create new client interceptors as below:
DateLog Client Interceptor
In interceptors folder, create new go file named datelogclientinterceptor.go as below:
package interceptors
import (
"context"
"fmt"
"time"
"google.golang.org/grpc"
)
func DateLogClientInterceptor(ctx context.Context, method string, req interface{}, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
today := time.Now()
fmt.Println("client call services date: " + today.Format("01/02/2006 15:04:05"))
err := invoker(ctx, method, req, reply, cc, opts...)
return err
}
MethodLog Client Interceptor
In interceptors folder, create new go file named methodlogclientinterceptor.go as below:
package interceptors
import (
"context"
"fmt"
"google.golang.org/grpc"
)
func MethodLogClientInterceptor(ctx context.Context, method string, req interface{}, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
fmt.Println("client call " + method + " service")
err := invoker(ctx, method, req, reply, cc, opts...)
return err
}
Create Client
In client folder, create new file named main.go as below:
package main
import (
interceptors "client/interceptors"
"context"
"fmt"
productservice "productservice/proto"
grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
"google.golang.org/grpc"
)
func main() {
conn, err := grpc.Dial(
":1111",
grpc.WithInsecure(),
grpc.WithUnaryInterceptor(
grpc_middleware.ChainUnaryClient(
interceptors.DateLogClientInterceptor,
interceptors.MethodLogClientInterceptor,
),
),
)
if err != nil {
fmt.Println(err)
}
defer conn.Close()
productServ := productservice.NewProductServiceClient(conn)
response1, err1 := productServ.FindAll(context.Background(), &productservice.FindAllRequest{})
if err1 != nil {
fmt.Println(err1)
} else {
products := response1.Products
fmt.Println("Product List")
for _, product := range products {
fmt.Println("id: ", product.Id)
fmt.Println("name: ", product.Name)
fmt.Println("price: ", product.Price)
fmt.Println("quantity: ", product.Quantity)
fmt.Println("status: ", product.Status)
fmt.Println("========================")
}
}
response2, err2 := productServ.Search(context.Background(), &productservice.SearchRequest{Keyword: "vi"})
if err2 != nil {
fmt.Println(err2)
} else {
products := response2.Products
fmt.Println("Search Products")
for _, product := range products {
fmt.Println("id: ", product.Id)
fmt.Println("name: ", product.Name)
fmt.Println("price: ", product.Price)
fmt.Println("quantity: ", product.Quantity)
fmt.Println("status: ", product.Status)
fmt.Println("========================")
}
}
}
Start Client
Select main.go file in client folder and open it in Terminal window of Visual Studio Code. Use command line as below to start client:
go run main.go
Output
client call services date: 08/19/2019 16:26:32
client call /productservice.ProductService/FindAll service
Product List
id: p01
name: tivi 1
price: 4.5
quantity: 4
status: true
========================
id: p02
name: tivi 2
price: 22
quantity: 3
status: false
========================
id: p03
name: laptop 3
price: 27
quantity: 3
status: true
========================
client call services date: 08/19/2019 16:26:32
client call /productservice.ProductService/Search service
Search Products
id: p01
name: tivi 1
price: 4.5
quantity: 4
status: true
========================
id: p02
name: tivi 2
price: 22
quantity: 3
status: false
========================
Structure of Project
