Add a cron to delete expired sessions

src/auth/session.go

@@ -11,6 +11,7 @@ import (
 
 	"git.handmade.network/hmn/hmn/src/config"
 	"git.handmade.network/hmn/hmn/src/db"
+	"git.handmade.network/hmn/hmn/src/logging"
 	"git.handmade.network/hmn/hmn/src/models"
 	"git.handmade.network/hmn/hmn/src/oops"
 	"github.com/jackc/pgx/v4/pgxpool"
@@ -94,3 +95,39 @@ var DeleteSessionCookie = &http.Cookie{
 	Domain: config.Config.Auth.CookieDomain,
 	MaxAge: -1,
 }
+
+func DeleteExpiredSessions(ctx context.Context, conn *pgxpool.Pool) (int64, error) {
+	tag, err := conn.Exec(ctx, "DELETE FROM sessions WHERE expires_at <= CURRENT_TIMESTAMP")
+	if err != nil {
+		return 0, oops.New(err, "failed to delete expired sessions")
+	}
+
+	return tag.RowsAffected(), nil
+}
+
+func PeriodicallyDeleteExpiredSessions(ctx context.Context, conn *pgxpool.Pool) <-chan struct{} {
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+
+		t := time.NewTicker(1 * time.Minute)
+		for {
+			select {
+			case <-t.C:
+				n, err := DeleteExpiredSessions(ctx, conn)
+				if err == nil {
+					if n > 0 {
+						logging.Info().Int64("num deleted sessions", n).Msg("Deleted expired sessions")
+					} else {
+						logging.Debug().Msg("no sessions to delete")
+					}
+				} else {
+					logging.Error().Err(err).Msg("Failed to delete expired sessions")
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return done
+}

src/website/website.go

@@ -8,6 +8,7 @@ import (
 	"os/signal"
 	"time"
 
+	"git.handmade.network/hmn/hmn/src/auth"
 	"git.handmade.network/hmn/hmn/src/config"
 	"git.handmade.network/hmn/hmn/src/db"
 	"git.handmade.network/hmn/hmn/src/logging"
@@ -31,6 +32,11 @@ var WebsiteCommand = &cobra.Command{
 			Handler: NewWebsiteRoutes(conn),
 		}
 
+		backgroundJobContext, cancelBackgroundJobs := context.WithCancel(context.Background())
+		backgroundJobsDone := zipJobs(
+			auth.PeriodicallyDeleteExpiredSessions(backgroundJobContext, conn),
+		)
+
 		signals := make(chan os.Signal, 1)
 		signal.Notify(signals, os.Interrupt)
 		go func() {
@@ -39,6 +45,7 @@ var WebsiteCommand = &cobra.Command{
 			timeout, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 			defer cancel()
 			server.Shutdown(timeout)
+			cancelBackgroundJobs()
 
 			<-signals
 			logging.Warn().Msg("Forcibly killed the website")
@@ -50,5 +57,18 @@ var WebsiteCommand = &cobra.Command{
 		if !errors.Is(serverErr, http.ErrServerClosed) {
 			logging.Error().Err(serverErr).Msg("Server shut down unexpectedly")
 		}
+
+		<-backgroundJobsDone
 	},
 }
+
+func zipJobs(cs ...<-chan struct{}) <-chan struct{} {
+	out := make(chan struct{})
+	go func() {
+		for _, c := range cs {
+			<-c
+		}
+		close(out)
+	}()
+	return out
+}