From 42811407a902749214ec6e8e7e1d88c1067f1771 Mon Sep 17 00:00:00 2001
From: Florent Messa <florent.messa@gmail.com>
Date: Mon, 25 Sep 2023 16:30:42 +0200
Subject: [PATCH] feat: free memory periodically

---
 cmd/picfit/main.go |  4 +---
 config/config.go   |  8 ++++++--
 server/http.go     | 26 +++++++++++++++++++++++---
 server/server.go   | 40 +++++++++++++++++++++++-----------------
 4 files changed, 53 insertions(+), 25 deletions(-)

diff --git a/cmd/picfit/main.go b/cmd/picfit/main.go
index 728145be..9de3558c 100644
--- a/cmd/picfit/main.go
+++ b/cmd/picfit/main.go
@@ -88,9 +88,7 @@ func main() {
 			os.Exit(1)
 		}
 
-		err := server.Run(context.Background(), config)
-
-		if err != nil {
+		if err := server.Run(context.Background(), config); err != nil {
 			fmt.Fprint(os.Stderr, err)
 			os.Exit(1)
 		}
diff --git a/config/config.go b/config/config.go
index 558da45a..1fe8ead7 100644
--- a/config/config.go
+++ b/config/config.go
@@ -39,6 +39,7 @@ type Options struct {
 	EnableUpload        bool          `mapstructure:"enable_upload"`
 	EnablePrometheus    bool          `mapstructure:"enable_prometheus"`
 	MimetypeDetector    string        `mapstructure:"mimetype_detector"`
+	FreeMemoryInterval  int           `mapstructure:"free_memory_interval"`
 }
 
 // Sentry is a struct to configure sentry using a dsn
@@ -125,11 +126,14 @@ func load(content string, isPath bool) (*Config, error) {
 		}
 	}
 
-	err = viper.Unmarshal(&config)
-	if err != nil {
+	if err = viper.Unmarshal(&config); err != nil {
 		return nil, err
 	}
 
+	if config.Options.FreeMemoryInterval == 0 {
+		config.Options.FreeMemoryInterval = 10
+	}
+
 	return config, nil
 }
 
diff --git a/server/http.go b/server/http.go
index 00c404a0..f3b7eeb0 100644
--- a/server/http.go
+++ b/server/http.go
@@ -1,6 +1,7 @@
 package server
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"net/http/pprof"
@@ -39,6 +40,10 @@ func NewHTTPServer(cfg *config.Config, processor *picfit.Processor) (*HTTPServer
 	return server, nil
 }
 
+func (s *HTTPServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	s.engine.ServeHTTP(w, req)
+}
+
 func (s *HTTPServer) Init() error {
 	var (
 		router    = gin.New()
@@ -223,8 +228,23 @@ func prometheusHandler() gin.HandlerFunc {
 }
 
 // Run loads a new http server
-func (s *HTTPServer) Run() error {
-	s.engine.Run(fmt.Sprintf(":%s", strconv.Itoa(s.config.Port)))
+func (s *HTTPServer) Run(ctx context.Context) error {
+	addr := fmt.Sprintf(":%s", strconv.Itoa(s.config.Port))
+	srv := &http.Server{
+		Addr:    addr,
+		Handler: s.engine.Handler(),
+	}
 
-	return nil
+	cerr := make(chan error)
+	go func() {
+		s.processor.Logger.Debug(fmt.Sprintf("Starting HTTP server on %s", addr))
+		cerr <- srv.ListenAndServe()
+	}()
+	select {
+	case err := <-cerr:
+		return err
+	case <-ctx.Done():
+		s.processor.Logger.Debug("Shutdown HTTP server")
+		return srv.Shutdown(context.Background())
+	}
 }
diff --git a/server/server.go b/server/server.go
index 23a2f5fb..2929862b 100644
--- a/server/server.go
+++ b/server/server.go
@@ -2,17 +2,16 @@ package server
 
 import (
 	"context"
-	"net/http"
+	"os/signal"
+	"runtime/debug"
+	"syscall"
+	"time"
 
 	"github.com/thoas/picfit"
 	"github.com/thoas/picfit/config"
 )
 
-type Server struct {
-	http *HTTPServer
-}
-
-func New(ctx context.Context, cfg *config.Config) (*Server, error) {
+func New(ctx context.Context, cfg *config.Config) (*HTTPServer, error) {
 	processor, err := picfit.NewProcessor(ctx, cfg)
 	if err != nil {
 		return nil, err
@@ -23,16 +22,7 @@ func New(ctx context.Context, cfg *config.Config) (*Server, error) {
 		return nil, err
 	}
 
-	server := &Server{http: httpServer}
-	return server, nil
-}
-
-func (s *Server) Run() error {
-	return s.http.Run()
-}
-
-func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	s.http.engine.ServeHTTP(w, req)
+	return httpServer, nil
 }
 
 // Run runs the application and launch servers
@@ -46,6 +36,22 @@ func Run(ctx context.Context, path string) error {
 	if err != nil {
 		return err
 	}
+	ctx, stop := signal.NotifyContext(ctx, syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+	if err := server.Run(ctx); err != nil {
+		return err
+	}
+
+	go func() {
+		for range time.Tick(time.Duration(cfg.Options.FreeMemoryInterval) * time.Second) {
+			debug.FreeOSMemory()
+		}
+	}()
+
+	select { // nolint:gosimple
+	case <-ctx.Done():
+		stop()
+	}
 
-	return server.Run()
+	return nil
 }