Graceful shutdown

package server

import (
  "context"
  "errors"
  "net/http"
  "os"
  "os/signal"
  "rgb/internal/conf"
  "rgb/internal/database"
  "rgb/internal/store"
  "syscall"
  "time"

  "github.com/rs/zerolog/log"
)

const InternalServerError = "Something went wrong!"

func Start(cfg conf.Config) {
  jwtSetup(cfg)

  store.SetDBConnection(database.NewDBOptions(cfg))

  router := setRouter()

  server := &http.Server{
    Addr:    cfg.Host + ":" + cfg.Port,
    Handler: router,
  }

  // Initializing the server in a goroutine so that
  // it won't block the graceful shutdown handling below
  go func() {
    if err := server.ListenAndServe(); err != nil && errors.Is(err, http.ErrServerClosed) {
      log.Error().Err(err).Msg("Server ListenAndServe error")
    }
  }()

  // Wait for interrupt signal to gracefully shutdown the server with
  // a timeout of 5 seconds.
  quit := make(chan os.Signal)
  // kill (no param) default send syscall.SIGTERM
  // kill -2 is syscall.SIGINT
  // kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
  signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
  <-quit
  log.Info().Msg("Shutting down server...")

  // The context is used to inform the server it has 5 seconds to finish
  // the request it is currently handling
  ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
  defer cancel()

  if err := server.Shutdown(ctx); err != nil {
    log.Fatal().Err(err).Msg("Server forced to shutdown")
  }

  log.Info().Msg("Server exiting.")
}