server: dump the cache when server shutting down

2 files changed, 47 insertions, 10 deletions

diff --git a/cmd/www-kbbi/main.go b/cmd/www-kbbi/main.go
index bb4cd86..7a959d5 100644
--- a/cmd/www-kbbi/main.go
+++ b/cmd/www-kbbi/main.go
@@ -28,4 +28,6 @@ func main() {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
 	<-c
+
+	server.Shutdown()
 }
diff --git a/server.go b/server.go
index a241f05..ec4aedd 100644
--- a/server.go
+++ b/server.go
@@ -9,6 +9,7 @@ import (
 	"log"
 	stdhttp "net/http"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/shuLhan/share/lib/http"
@@ -32,6 +33,9 @@ type Server struct {
 	// If offline is true and the word definition is not found on cache,
 	// the server will not forward request to official KBBI server.
 	offline bool
+
+	wg      sync.WaitGroup
+	stopped chan bool
 }
 
 //
@@ -42,7 +46,9 @@ func NewServer() (server *Server, err error) {
 		Address: defListen,
 	}
 
-	server = &Server{}
+	server = &Server{
+		stopped: make(chan bool, 1),
+	}
 
 	server.kamus, err = newKamusCache("")
 	if err != nil {
@@ -72,27 +78,56 @@ func NewServer() (server *Server, err error) {
 //
 func (server *Server) Start() (err error) {
 	go server.dumpCache()
+	server.wg.Add(1)
 
 	return server.http.Start()
 }
 
 //
-// dumpCache periodically dump the cache to file to be loaded later.
+// Shutdown the HTTP server and save the cache for future use.
 //
-func (server *Server) dumpCache() {
+func (server *Server) Shutdown() (err error) {
+	err = server.Shutdown()
+
+	server.stopped <- true
+
+	// Wait for all jobs to be completed.
+	server.wg.Wait()
+
+	return err
+}
+
+//
+// dumpCacheJob periodically save the cache or when the server stopped.
+//
+func (server *Server) dumpCacheJob() {
 	ticker := time.NewTicker(1 * time.Hour)
 
-	for range ticker.C {
-		if !server.kamus.isChanging() {
-			continue
-		}
-		err := server.kamus.store()
-		if err != nil {
-			log.Println("server.dumpCache: ", err)
+	for {
+		select {
+		case <-ticker.C:
+			server.dumpCache()
+		case <-server.stopped:
+			server.dumpCache()
+			server.wg.Done()
+			return
 		}
 	}
 }
 
+//
+// dumpCache to storage to be loaded later.
+//
+func (server *Server) dumpCache() {
+	if !server.kamus.isChanging() {
+		return
+	}
+	err := server.kamus.store()
+	if err != nil {
+		log.Println("server.dumpCache: ", err)
+	}
+}
+
 func (server *Server) handleDefinisi(
 	httpRes stdhttp.ResponseWriter,
 	httpReq *stdhttp.Request,