more serve cmd and post updates

commands/serve.go

@@ -88,7 +88,6 @@ func runWatcher(config *config.Config) (*fsnotify.Watcher, *EventBroker, error)
 	if err != nil {
 		return nil, nil, err
 	}
-	defer watchProjectFiles(watcher, config)
 
 	broker := newEventBroker()
 
@@ -119,21 +118,8 @@ func runWatcher(config *config.Config) (*fsnotify.Watcher, *EventBroker, error)
 	return watcher, broker, err
 }
 
-// Configure the given watcher to notify for changes in the project source files
-func watchProjectFiles(watcher *fsnotify.Watcher, config *config.Config) error {
-	watcher.Add(config.LayoutsDir)
-	watcher.Add(config.DataDir)
-	watcher.Add(config.IncludesDir)
-	// fsnotify watches all files within a dir, but non recursively
-	// this walks through the src dir and adds watches for each found directory
-	return filepath.WalkDir(config.SrcDir, func(path string, entry fs.DirEntry, err error) error {
-		if entry.IsDir() {
-			watcher.Add(path)
-		}
-		return nil
-	})
-}
-
+// React to source file change events by re-watching the source directories,
+// rebuilding the site and publishing a rebuild event to clients.
 func rebuildSite(config *config.Config, watcher *fsnotify.Watcher, broker *EventBroker) {
 	fmt.Printf("building site\n")
 
@@ -153,6 +139,21 @@ func rebuildSite(config *config.Config, watcher *fsnotify.Watcher, broker *Event
 	fmt.Println("done\nserving at", config.SiteUrl)
 }
 
+// Configure the given watcher to notify for changes in the project source files
+func watchProjectFiles(watcher *fsnotify.Watcher, config *config.Config) error {
+	watcher.Add(config.LayoutsDir)
+	watcher.Add(config.DataDir)
+	watcher.Add(config.IncludesDir)
+	// fsnotify watches all files within a dir, but non recursively
+	// this walks through the src dir and adds watches for each found directory
+	return filepath.WalkDir(config.SrcDir, func(path string, entry fs.DirEntry, err error) error {
+		if entry.IsDir() {
+			watcher.Add(path)
+		}
+		return nil
+	})
+}
+
 // Tweaks the http file system to construct a server that hides the .html suffix from requests.
 // Based on https://stackoverflow.com/a/57281956/993769
 type HTMLFileSystem struct {

docs/src/blog/a-site-server-with-live-reload.org

@@ -81,7 +81,6 @@ func runWatcher(config *config.Config) {
 			// new src directories could be triggering this event
 			// so project files need to be re-added every time
 			watchProjectFiles(watcher, config)
-
 			site.Build(*config)
 		}
 	}()
@@ -101,6 +100,35 @@ func watchProjectFiles(watcher *fsnotify.Watcher, config *config.Config) {
 }
 #+end_src
 
+- delay to prevent bursts
+
+#+begin_src diff
+func runWatcher(config *config.Config) {
+	watcher, _ := fsnotify.NewWatcher()
+-	defer watchProjectFiles(watcher, config)
++
++	rebuildAfter := time.AfterFunc(0, func() {
++		watchProjectFiles(watcher, config)
++		site.Build(*config)
++	})
+
+	go func() {
+		for event := range watcher.Events {
+			fmt.Printf("\nfile %s changed, rebuilding site\n", event.Name)
+
+-			watchProjectFiles(watcher, config)
+-			site.Build(*config)
++			// Schedule a rebuild to trigger after a delay.
++			// If there was another one pending it will be canceled.
++			rebuildAfter.Stop()
++			rebuildAfter.Reset(100 * time.Millisecond)
+
+
+		}
+	}()
+}
+#+end_src
+
 *** Build optimizations
 - optimization: worker pool
 
@@ -173,6 +201,7 @@ func (site *site) build() error {
 }
 #+end_src
 
+- in other languages, a similar change would have required adding async/await statements on half of my codebase.
 - optimization: ln static files
 
 *** Live reload
@@ -250,23 +279,27 @@ newSSE();
 -func runWatcher(config *config.Config) {
 +func runWatcher(config *config.Config) *EventBroker {
 	watcher, _ := fsnotify.NewWatcher()
-	defer watchProjectFiles(watcher, config)
 +	broker := newEventBroker()
 
+	rebuildAfter := time.AfterFunc(0, func() {
+		watchProjectFiles(watcher, config)
+		site.Build(*config)
++		broker.publish("rebuild")
+	})
+
+
 	go func() {
 		for event := range watcher.Events {
 			fmt.Printf("\nfile %s changed, rebuilding site\n", event.Name)
 
-			// new src directories could be triggering this event
-			// so project files need to be re-added every time
-			watchProjectFiles(watcher, config)
+			// Schedule a rebuild to trigger after a delay.
+			// If there was another one pending it will be canceled.
+			rebuildAfter.Stop()
+			rebuildAfter.Reset(100 * time.Millisecond)
 
-			site.Build(*config)
-+			broker.publish("rebuild")
 		}
 	}()
 
 +	return broker
 }
 #+end_src
-- delay to prevent bursts