feat: graceful shutdown server (#1016)

bin/server/main.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	"net/http"
 	"os"
+	"os/signal"
+	"syscall"
 
 	_ "github.com/mattn/go-sqlite3"
-	"github.com/pkg/errors"
 
 	"context"
 	"fmt"
@@ -24,11 +26,11 @@ const (
 `
 )
 
-func run() error {
-	ctx := context.Background()
+func main() {
 	profile, err := profile.GetProfile()
 	if err != nil {
-		return err
+		fmt.Printf("failed to get profile, error: %+v\n", err)
+		return
 	}
 	println("---")
 	println("profile")
@@ -38,19 +40,35 @@ func run() error {
 	println("version:", profile.Version)
 	println("---")
 
-	serverInstance, err := server.NewServer(ctx, profile)
+	ctx, cancel := context.WithCancel(context.Background())
+	s, err := server.NewServer(ctx, profile)
 	if err != nil {
-		return errors.Wrap(err, "failed to start server")
+		cancel()
+		fmt.Printf("failed to create server, error: %+v\n", err)
+		return
 	}
 
+	c := make(chan os.Signal, 1)
+	// Trigger graceful shutdown on SIGINT or SIGTERM.
+	// The default signal sent by the `kill` command is SIGTERM,
+	// which is taken as the graceful shutdown signal for many systems, eg., Kubernetes, Gunicorn.
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		sig := <-c
+		fmt.Printf("%s received.\n", sig.String())
+		s.Shutdown(ctx)
+		cancel()
+	}()
+
 	println(greetingBanner)
 	fmt.Printf("Version %s has started at :%d\n", profile.Version, profile.Port)
-	return serverInstance.Start(ctx)
-}
-
-func main() {
-	if err := run(); err != nil {
-		fmt.Printf("error: %+v\n", err)
-		os.Exit(1)
+	if err := s.Start(ctx); err != nil {
+		if err != http.ErrServerClosed {
+			fmt.Printf("failed to start server, error: %+v\n", err)
+			cancel()
+		}
 	}
+
+	// Wait for CTRL-C.
+	<-ctx.Done()
 }