GO GRPC BASIC

Requirements ( Do It Letter )

Setup Project

• create proto dir
• create versioning dir and service dir health
• create proto file health.proto
• compile / generate proto with compile-proto.sh in proto dir

Setup config file

• create config.yaml
• create pkg dir , create versioning dir and create configs dir
• go get gopkg.in/yaml.v2 , is a lib for parsing yaml config file to struct
• create config.go file, implement New and other func
• create configs dir on root project , create configs.go, this is file that bundle or wrap any services or packages
• go get github.com/sirupsen/logrus, is a lib to show log on run
• implement New to configs.go file
• create main.go, implement to call config and log environtment read is ready
• test go run .

Implement Server GRPC

• create utils/constants dir in pkg/v1, to create global constants, implement EnvProduction, Successcode, SuccessDesc
• implement grpc service create api/v1/health service, create health.go as server service
• create api/v1/health/status.go as method implment from protobuf / pb file
• create router dir in root project
• create grpc.go in router dir and implement NewGRPCServer and register health api service
• go get github.com/soheilhy/cmux, is for ?
• create router.go in router dir and implement IgnoreErr, this is for ignore error so can be safely ignore
• go get golang.org/x/sync/errgroup, is for ?
• implement main.go to create grpc server from grpc.go with errgroup handler
• go run ., run server grpc
• go install github.com/fullstorydev/grpcurl/cmd/grpcurl@latest
• test grpcurl -plaintext localhost:5566 list, to show list name of services
• test grpcurl -plaintext localhost:5566 list api.gogrpc.v1.health.HealthService, to show list name of service methods
• test grpcurl -plaintext localhost:5566 api.gogrpc.v1.health.HealthService.Status, to test method call in grpc
• result

{
    "success": true,
    "code": "0000",
    "desc": "SUCCESS"
}

• or test via postman , new -> grpc request -> Enter Server Url : localhost:5566 -> Import proto file / Select Method : Status -> Click Invoke

Implement gRPC-Gateway

ref https://github.com/grpc-ecosystem/grpc-gateway

• implement import "google/api/annotations.proto"; in proto file
• changes line below in all service methods for rest compile to rest

service HealthService {
    rpc Status(google.protobuf.Empty) returns (Response) {
        + option (google.api.http) = {
        +    get: "/api/gogrpc/v1/health/status"
        + };
    }
}

• re - compile / re - generate proto with compile-proto.sh in proto dir
• go mod tidy
• go get "github.com/gorilla/handlers"
• create http.go in router dir and implement NewHTTPServer and register health api service
• register httpserver to main.go

g.Go(func() error { return router.NewHTTPServer(configs, logger) })

• go run . run grpc and http server
• test curl localhost:8080/api/v1/health/status, reponse

{
    "success":true,
    "code":"0000",
    "desc":"SUCCESS"
}

• GENERATE API DOCS:
• mkdir swagger
• cd proto
• ./gen-apidoc.sh
• register apidoc to http server in http.go implement

#########

if configs.Config.Env != constants.EnvProduction {
	CreateSwagger(mux)
}

##########

func CreateSwagger(gwmux *http.ServeMux) {
	gwmux.HandleFunc("/api/health/docs.json", func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, "swagger/docs.json")
	})
}

Implement DB_Connection (With PostgreSQL)

• Execute example.sql in db, you know how to do it
• add config.yaml with line below

postgres:
  host: 127.0.0.1
  port: 5432
  dbname: test
  username: postgres
  password: mysecretpassword

• changes pkg/v1/config/config.go to add new config line in config struct and and validateConfigData rule
• go get github.com/lib/pq
• create pkg/v1/postgres dir, create postgres.go file in there implement string conn and test connection
• create pkg/v1/utils/converter dir, create converter.go file in there, to convert camelcase to snake_case
• create pkg/v1/postgres/custom.main.go to implement all query to database table custom
• changes configs/configs.go to bundle pg connection
• how to use custom.main.go call function from custom main in api status, check api/v1/health/status.go