[Go] Lambda CRUD với Postgres

Prepare

create simple lambda function, read blog: https://viblo.asia/p/golang-aws-lambda-thong-qua-serverless-framework-phan-1-EoW4ob9xVml
handle request and response in api: https://viblo.asia/p/golang-aws-lambda-thong-qua-serverless-framework-phan-2-5pPLkPY8VRZ

Mục tiêu

add new user
get user by id
update user
delete user

Khởi tạo project

Ở series này mình dùng serverless để làm việc với lambda(env, create, deploy,..)
Để biết chi tiết hơn, checkout link đọc thêm.

Script create table:

sql create table user

CREATETABLE"users"("id" bigserial,
  username charactervarying(50)COLLATE pg_catalog."default",
  name charactervarying(50)COLLATE pg_catalog."default"NOTNULL,
  phone charactervarying(50)COLLATE pg_catalog."default",PRIMARYKEY("id"));

model database

type UserModel struct{
  ID       uint`gorm:"primarykey"`
  UserName string`gorm:"column:username" bson:"username"`
  Email    string`gorm:"column:email" bson:"email"`
  Phone    string`gorm:"column:phone" bson:"phone"`}

List function

file serverless: https://github.com/ducnpdev/open-dev/blob/master/aws/lambda/crud/serverless.yml

Thêm 1 user

tạo endpoint trong file serverless:

functions:create:handler: bin/create # file binary sau khi buildtimeout:3# thời gian tối đa của functoin có thể xử lý memorySize:512# resource memory được cấp phát cho function,description: create new user
    events:-http:path: /create # context-pathmethod: post # method

Code implement:

function connection đến postgres database:

// load env from os, cast to structfuncloadConfig() Postgres {// những value khi get từ os lên thì đã được define trong file serverless.yaml
    user := os.Getenv("DB_USER")
    dbpass := os.Getenv("DB_PASS")
    dbhost := os.Getenv("DB_HOST")
    dbservice := os.Getenv("DB_SERVICE")return Postgres{
      Username: user,
      Password: dbpass,
      Database: dbservice,
      Host:     dbhost,
      Port:5432,}}// create database postgres instancefuncInitPostgres()(*gorm.DB,error){
    log.Default().Println("connecting postgres database")
    config :=loadConfig()
    dsn := fmt.Sprintf("host=%s user=%s password=%s dbname=%s port=%d ", config.Host, config.Username, config.Password, config.Database, config.Port)
    db, err := gorm.Open(postgres.Open(dsn),&gorm.Config{})if err !=nil{
        log.Default().Println("connect postgres err:", err)return db, err
    }
    log.Default().Println("connect postgres successfully")return db, err
}

struct nhận request client:

type UserDTO struct{
  Email string`json:"email"`
  User  string`json:"userName"`
  Phone string`json:"phone"`}

main function của lambda

funcmain(){
    lambda.Start(CreateUser)}

function response data

funcParseResponse(respBody HttpResponse)string{
  respBody.Time = time.Now().Format("2006-01-02T15:04:05.000-07:00")if respBody.Err !=nil{returnresponseErr(respBody)}returnresponseOk(respBody)}funcresponseOk(respBody HttpResponse)string{var buf bytes.Buffer
  mapRes :=map[string]interface{}{"responseId":      respBody.Uuid,"responseMessage":"successfully","responseTime":    respBody.Time,}if respBody.Data !=nil{
    mapRes["data"]= respBody.Data
  }
  body, errMarshal := json.Marshal(mapRes)if errMarshal !=nil{
    log.Default().Println("marshal response err", errMarshal)}
  json.HTMLEscape(&buf, body)return buf.String()}funcresponseErr(respBody HttpResponse)string{var buf bytes.Buffer
  mapRes :=map[string]interface{}{"responseId":      respBody.Uuid,"responseMessage": respBody.Err.Error(),"responseTime":    respBody.Time,}

  body, errMarshal := json.Marshal(mapRes)if errMarshal !=nil{
    log.Default().Println("marshal response err", errMarshal)}
  json.HTMLEscape(&buf, body)return buf.String()}

function createUser

funcCreateUser(ctx context.Context,
  eventReq events.APIGatewayProxyRequest)(Response,error){var(
    req  = RequestBodyAPIGW{}
    resp = Response{
      StatusCode:400,
      IsBase64Encoded:false,
      Headers:map[string]string{"Content-Type":"application/json",},})
  err := json.Unmarshal([]byte(eventReq.Body),&req)if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})return resp,nil}
  db, err := pkg.InitPostgres()if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})
    resp.StatusCode =500return resp,nil}// set http-code 200
  resp.StatusCode =200// save new user
  err = db.Debug().Exec(`insert into users(username,email,phone) values(?,?,?)`, req.Data.User, req.Data.Email, req.Data.Phone).Error
  if err !=nil{
    resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Err: err})return resp,nil}
  resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Data:nil})return resp,nil}

Get user by id

tạo endpoint trong file serverless:

functions:read:handler: bin/read
    description: get user detail by id
    events:-http:path: /read
          method: get

Code implement:

Struct nhận request từ client

type UserDTO struct{
  ID string`json:"userId"`}

function get user detail by id

funcReadUser(ctx context.Context,
  eventReq events.APIGatewayProxyRequest)(Response,error){var(
    req  = RequestBodyAPIGW{}
    resp = Response{
      StatusCode:400,
      IsBase64Encoded:false,
      Headers:map[string]string{"Content-Type":"application/json",},})// get parameter from url
  req.Data.ID = eventReq.QueryStringParameters["id"]// init database,
  db, err := pkg.InitPostgres()if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})
    resp.StatusCode =500return resp,nil}
  resp.StatusCode =200var user = models.UserModel{}
  err = db.Table("users").Where("id = ?", req.Data.ID).First(&user).Error
  if err !=nil{
    resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Err: err})return resp,nil}
  resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Data: user})return resp,nil}

Get update user

tạo endpoint trong file serverless

functions:
  update:
    handler: bin/update
    description: update user by id
    events:
      - http:
          path: /update
          method: post

Struct nhận request từ client

type UserDTO struct{
    ID    int`json:"userId"`
    Email string`json:"email"`
    Phone string`json:"phone"`}

Code implement

function get update user

funcUpdateUser(ctx context.Context, eventReq events. APIGatewayProxyRequest)(Response,error){var(
    req  = RequestBodyAPIGW{}
    resp = Response{
      StatusCode:400,
      IsBase64Encoded:false,
      Headers:map[string]string{"Content-Type":"application/json",},})
  err := json.Unmarshal([]byte(eventReq.Body),&req)if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})return resp,nil}
  db, err := pkg.InitPostgres()if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})
    resp.StatusCode =500return resp,nil}
  resp.StatusCode =200
  err = db.Exec(`update users set email = ?, phone = ? where id = ?`, req.Data.Email, req.Data.Phone, req.Data.ID).Error
  if err !=nil{
    resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Err: err})return resp,nil}
  resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Data:nil})return resp,nil}

Detele user

tạo endpoint trong file serverless

functions:
  delete:
    handler: bin/delete
    description: delete user by id
    events:
      - http:
          path: /delete
          method: post

Struct nhận request từ client

type UserDTO struct{
    ID    int`json:"userId"`}

Code implement

function get delete user by id

funcDeleteUser(ctx context.Context, eventReq events.APIGatewayProxyRequest)(Response,error){var(
    req  = RequestBodyAPIGW{}
    resp = Response{
      StatusCode:400,
      IsBase64Encoded:false,
      Headers:map[string]string{"Content-Type":"application/json",},})
  err := json.Unmarshal([]byte(eventReq.Body),&req)if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})return resp,nil}
  db, err := pkg.InitPostgres()if err !=nil{
    resp.Body =ParseResponse(HttpResponse{
      Uuid: req.RequestID,
      Err:  err,})
    resp.StatusCode =500return resp,nil}
  resp.StatusCode =200var user = models.UserModel{}
  err = db.Debug().Table("users").Delete(&user, req.Data.ID).Error
  if err !=nil{
    resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Err: err})return resp,nil}
  resp.Body =ParseResponse(HttpResponse{Uuid: req.RequestID, Data: req.Data})return resp,nil}

Nguồn: viblo.asia

Prepare

Mục tiêu

Khởi tạo project

Script create table:

List function

Thêm 1 user

Get user by id

Get update user

Detele user

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