refactor code for context fallthrough

cmd/mochi/main.go

@@ -37,7 +37,7 @@ func main() {
 	if err := s.Run(*configPath); err != nil {
 		log.Fatal("unable to start server: ", err)
 	}
-	defer s.Dispose()
+	defer s.Shutdown()
 	ch := make(chan os.Signal, 2)
 	signal.Notify(ch, os.Interrupt, syscall.SIGTERM)
 	<-ch

cmd/mochi/server.go

@@ -3,20 +3,23 @@ package main
 import (
 	"errors"
 	"fmt"
+	"io"
+	"sync"
+
+	"github.com/rs/zerolog"
 
 	"github.com/sot-tech/mochi/frontend"
 	"github.com/sot-tech/mochi/middleware"
 	"github.com/sot-tech/mochi/pkg/log"
 	"github.com/sot-tech/mochi/pkg/metrics"
-	"github.com/sot-tech/mochi/pkg/stop"
 	"github.com/sot-tech/mochi/storage"
 )
 
 // Server represents the state of a running instance.
 type Server struct {
-	storage storage.PeerStorage
-	logic   *middleware.Logic
-	sg      *stop.Group
+	frontends []io.Closer
+	hooks     []io.Closer
+	storage   storage.PeerStorage
 }
 
 // Run begins an instance of Conf.
@@ -28,11 +31,9 @@ func (r *Server) Run(configFilePath string) error {
 		return fmt.Errorf("failed to read config: %w", err)
 	}
 
-	r.sg = stop.NewGroup()
-
 	if len(cfg.MetricsAddr) > 0 {
 		log.Info().Str("address", cfg.MetricsAddr).Msg("starting metrics server")
-		r.sg.Add(metrics.NewServer(cfg.MetricsAddr))
+		r.frontends = append(r.frontends, metrics.NewServer(cfg.MetricsAddr))
 	} else {
 		log.Info().Msg("metrics disabled because of empty address")
 	}
@@ -46,17 +47,30 @@ func (r *Server) Run(configFilePath string) error {
 	if err != nil {
 		return fmt.Errorf("failed to configure pre-hooks: %w", err)
 	}
+
+	for _, h := range preHooks {
+		if c, isOk := h.(io.Closer); isOk {
+			r.hooks = append(r.hooks, c)
+		}
+	}
+
 	postHooks, err := middleware.NewHooks(cfg.PostHooks, r.storage)
 	if err != nil {
 		return fmt.Errorf("failed to configure post-hooks: %w", err)
 	}
 
+	for _, h := range postHooks {
+		if c, isOk := h.(io.Closer); isOk {
+			r.hooks = append(r.hooks, c)
+		}
+	}
+
 	if len(cfg.Frontends) > 0 {
 		var fs []frontend.Frontend
-		r.logic = middleware.NewLogic(cfg.AnnounceInterval, cfg.MinAnnounceInterval, r.storage, preHooks, postHooks)
-		if fs, err = frontend.NewFrontends(cfg.Frontends, r.logic); err == nil {
+		logic := middleware.NewLogic(cfg.AnnounceInterval, cfg.MinAnnounceInterval, r.storage, preHooks, postHooks)
+		if fs, err = frontend.NewFrontends(cfg.Frontends, logic); err == nil {
 			for _, f := range fs {
-				r.sg.Add(f)
+				r.frontends = append(r.frontends, f)
 			}
 		} else {
 			err = fmt.Errorf("failed to configure frontends: %w", err)
@@ -68,21 +82,50 @@ func (r *Server) Run(configFilePath string) error {
 	return err
 }
 
-// Dispose shuts down an instance of Server.
-func (r *Server) Dispose() {
+// Shutdown shuts down an instance of Server.
+func (r *Server) Shutdown() {
 	log.Debug().Msg("stopping frontends and metrics server")
-	if errs := r.sg.Stop().Wait(); len(errs) > 0 {
-		log.Error().Errs("errors", errs).Msg("error occurred while shutting down frontends")
-	}
+	closeGroup(r.frontends).Msg("frontends stopped")
 
-	log.Debug().Msg("stopping logic")
-	if errs := r.logic.Stop().Wait(); len(errs) > 0 {
-		log.Error().Errs("errors", errs).Msg("error occurred while shutting down middlewares")
-	}
+	log.Debug().Msg("stopping middleware")
+	closeGroup(r.hooks).Msg("hooks stopped")
 
 	log.Debug().Msg("stopping peer store")
-	if errs := r.storage.Stop().Wait(); len(errs) != 0 {
-		log.Error().Errs("errors", errs).Msg("error occurred while shutting down peer store")
+	var err error
+	if r.storage != nil {
+		err = r.storage.Close()
+	} else {
+		err = errors.New("peer store not configured")
 	}
+	log.Err(err).Msg("peer store stopped")
 	log.Close()
 }
+
+func closeGroup(cls []io.Closer) (e *zerolog.Event) {
+	l := len(cls)
+	errs := make([]error, l)
+	wg := sync.WaitGroup{}
+	wg.Add(l)
+	for i, cl := range cls {
+		go func(i int, cl io.Closer) {
+			defer wg.Done()
+			if e := cl.Close(); e != nil {
+				errs[i] = e
+			}
+		}(i, cl)
+	}
+	wg.Wait()
+	nnErrs := make([]error, 0, l)
+	for _, e := range errs {
+		if e != nil {
+			nnErrs = append(nnErrs, e)
+		}
+	}
+	var evt *zerolog.Event
+	if len(nnErrs) > 0 {
+		evt = log.Error().Errs("errors", nnErrs)
+	} else {
+		evt = log.Info()
+	}
+	return evt
+}