Shut down cleanly when 'api serve' is interrupted

This will properly close the db and, more particularly, flush out any
profile files being written. Otherwise, they can end up empty or
truncated.

Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>

cmd/api_serve.go

@@ -1,11 +1,15 @@
 package cmd
 
 import (
+	stdcontext "context"
+	"errors"
 	"fmt"
 	"net"
 	"net/http"
 	"net/url"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"github.com/aptly-dev/aptly/api"
 	"github.com/aptly-dev/aptly/systemd/activation"
@@ -55,6 +59,17 @@ func aptlyAPIServe(cmd *commander.Command, args []string) error {
 	listen := context.Flags().Lookup("listen").Value.String()
 	fmt.Printf("\nStarting web server at: %s (press Ctrl+C to quit)...\n", listen)
 
+	server := http.Server{Handler: api.Router(context)}
+
+	sigchan := make(chan os.Signal, 1)
+	signal.Notify(sigchan, syscall.SIGINT, syscall.SIGTERM)
+	go (func() {
+		if _, ok := <-sigchan; ok {
+			server.Shutdown(stdcontext.Background())
+		}
+	})()
+	defer close(sigchan)
+
 	listenURL, err := url.Parse(listen)
 	if err == nil && listenURL.Scheme == "unix" {
 		file := listenURL.Path
@@ -67,19 +82,17 @@ func aptlyAPIServe(cmd *commander.Command, args []string) error {
 		}
 		defer listener.Close()
 
-		err = http.Serve(listener, api.Router(context))
-		if err != nil {
-			return fmt.Errorf("unable to serve: %s", err)
-		}
-		return nil
+		err = server.Serve(listener)
+	} else {
+		server.Addr = listen
+		err = server.ListenAndServe()
 	}
 
-	err = http.ListenAndServe(listen, api.Router(context))
-	if err != nil {
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
 		return fmt.Errorf("unable to serve: %s", err)
 	}
 
-	return err
+	return nil
 }
 
 func makeCmdAPIServe() *commander.Command {