main.go for working with mysql

main.go

package main

import (
	"context"
	"os"

	"aws-golang-lambda/api/handler"
	"aws-golang-lambda/usecase/users"

	mysqldb "aws-golang-lambda/repository/mysql"

	"github.com/aws/aws-lambda-go/events"
	"github.com/aws/aws-lambda-go/lambda"
	ginadapter "github.com/awslabs/aws-lambda-go-api-proxy/gin"
	"github.com/gin-gonic/gin"
	"github.com/jmoiron/sqlx"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
)

var (
	ginLambda *ginadapter.GinLambda
	srv       *users.Service
	secret    string
)

func init() {
	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
	zerolog.SetGlobalLevel(zerolog.DebugLevel)
	logger := log.With().Logger()

	secret = os.Getenv("JWT_SECRET")
	if secret == "" {
		logger.Panic().
			Msg("jwt secret environment varialbe is missing")
	}

	// make sure to store it in a secure way, such as ssm/secrets manager
	db, err := sqlx.Connect("mysql", "myuser:password@(<MY DATABASE HOST>:3306)/usersdb")
	if err != nil {
		logger.Panic().
			Err(err).
			Msg("unable to connect to mysql database")
	}

	repo := mysqldb.NewMysqlDB(db)

	srv = users.LoadService(repo, &logger)

	gin.SetMode(gin.ReleaseMode)
	r := handler.NewGinHandler(srv, secret)
	ginLambda = ginadapter.New(r)
}

func Handler(ctx context.Context, req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
	return ginLambda.ProxyWithContext(ctx, req)
}

func main() {
	lambda.Start(Handler)
}