Adding graceful server shutdown

.air.toml

@@ -16,7 +16,7 @@ tmp_dir = "tmp"
   include_dir = []
   include_ext = ["go", "tpl", "tmpl", "html", "go.tmpl"]
   include_file = []
-  kill_delay = "0s"
+  kill_delay = "1s"
   log = "build-errors.log"
   poll = false
   poll_interval = 0
@@ -24,7 +24,7 @@ tmp_dir = "tmp"
   pre_cmd = []
   rerun = false 
   rerun_delay = 500
-  send_interrupt = false
+  send_interrupt = true
   stop_on_error = false
 
 [color]

README.md

@@ -52,6 +52,7 @@ The `ratchetd` cmd binary uses Oauth so you will need to create a new Oauth App.
 
 ## Additional Resources
 
+- [Graceful Shutdown](https://dev.to/mokiat/proper-http-shutdown-in-go-3fji)
 - [Content Range Requests](https://web.archive.org/web/20230918195519/https://benramsey.com/blog/2008/05/206-partial-content-and-range-requests/)
 - [HTTP 204 and 205 Status Codes](https://web.archive.org/web/20230918193536/https://benramsey.com/blog/2008/05/http-status-204-no-content-and-205-reset-content/)
 - [How to Disable FileServer Directory Listings](https://www.alexedwards.net/blog/disable-http-fileserver-directory-listings)

cmd/ratchetd/main.go

@@ -1,12 +1,17 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
+	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/http"
 	"os"
+	"os/signal"
+	"syscall"
 	"time"
 
 	rdb "git.runcible.io/learning/ratchet/internal/database"
@@ -22,17 +27,20 @@ import (
 // 	commit  string
 // )
 
-func main() {
+func run(ctx context.Context, w io.Writer, args []string) error {
 	// CONFIGURATION
 	// Parse command line options
-	addr := flag.String("addr", "0.0.0.0", "HTTP network address")
-	port := flag.String("port", "5001", "HTTP port")
-	logLevel := flag.String("logging", "INFO", "Logging Level. Valid values [INFO, DEBUG, WARN, ERROR].")
-	dbPath := flag.String("database", "./ratchet.db", "A path to a sqlite3 database")
-	certPath := flag.String("cert", "./tls/cert.pem", "A public cert in .pem format")
-	keyPath := flag.String("key", "./tls/key.pem", "A private key in .pem format")
+	flags := flag.NewFlagSet(args[0], flag.ExitOnError)
+	addr := flags.String("addr", "0.0.0.0", "HTTP network address")
+	port := flags.String("port", "5001", "HTTP port")
+	logLevel := flags.String("logging", "INFO", "Logging Level. Valid values [INFO, DEBUG, WARN, ERROR].")
+	dbPath := flags.String("database", "./ratchet.db", "A path to a sqlite3 database")
+	certPath := flags.String("cert", "./tls/cert.pem", "A public cert in .pem format")
+	keyPath := flags.String("key", "./tls/key.pem", "A private key in .pem format")
 	// must call parse or all values will be the defaults
-	flag.Parse()
+	if err := flags.Parse(args[1:]); err != nil {
+		return err
+	}
 
 	// DEPENDENCY INJECTION FOR HANDLERS
 	// Setup Logging
@@ -41,17 +49,22 @@ func main() {
 	db, err := rdb.OpenSqlite3DB(*dbPath)
 
 	if err != nil {
-		slog.Error(err.Error())
-		os.Exit(1)
+		return err
 	}
 	// Close db connection before exiting main.
-	defer db.Close()
+	defer func() {
+		slog.Info("Cleaning up database")
+		_, err := db.Exec("PRAGMA wal_checkpoint(TRUNCATE)")
+		if err != nil {
+			slog.Error(fmt.Sprintf("Error checkpointing database: %v", err))
+		}
+		db.Close()
+	}()
 
 	//tc, err := server.InitTemplateCache()
 	tc, err := server.InitFSTemplateCache()
 	if err != nil {
-		slog.Error(err.Error())
-		os.Exit(1)
+		return err
 	}
 
 	// SessionManager
@@ -126,8 +139,37 @@ func main() {
 
 	slog.Info(fmt.Sprintf("Listening on https://%s", srv.Addr))
 
-	err = srv.ListenAndServeTLS(*certPath, *keyPath)
-	slog.Error(err.Error())
-	os.Exit(1)
+	go func() {
+		if err = srv.ListenAndServeTLS(*certPath, *keyPath); !errors.Is(err, http.ErrServerClosed) {
+			slog.Error(err.Error())
+			os.Exit(1)
+		}
+		slog.Info("Stopped serving connections")
+	}()
+
+	// Handle  graceful shutdown
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	// Block until signal is recieved
+	<-sigChan
 
+	shutdownCtx, shutdownRelease := context.WithTimeout(ctx, 10*time.Second)
+	defer shutdownRelease()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		slog.Error("Failed to close within context timeout. Forcing server close.")
+		srv.Close()
+		return err
+	}
+
+	return nil
+
+}
+
+func main() {
+	ctx := context.Background()
+	if err := run(ctx, os.Stdout, os.Args); err != nil {
+		slog.Error(err.Error())
+		os.Exit(1)
+	}
 }