Allow rendering static files to disk and dynamic to memory in server mode

Updates #9625

commands/commandeer.go

@@ -92,6 +92,7 @@ type commandeer struct {
 	languagesConfigured bool
 	languages           langs.Languages
 	doLiveReload        bool
+	renderStaticToDisk  bool
 	fastRenderMode      bool
 	showErrorInBrowser  bool
 	wasError            bool
@@ -368,8 +369,9 @@ func (c *commandeer) loadConfig() error {
 	}
 
 	createMemFs := config.GetBool("renderToMemory")
+	c.renderStaticToDisk = config.GetBool("renderStaticToDisk")
 
-	if createMemFs {
+	if createMemFs && !c.renderStaticToDisk {
 		// Rendering to memoryFS, publish to Root regardless of publishDir.
 		config.Set("publishDir", "/")
 	}
@@ -380,6 +382,14 @@ func (c *commandeer) loadConfig() error {
 		if c.destinationFs != nil {
 			// Need to reuse the destination on server rebuilds.
 			fs.Destination = c.destinationFs
+		} else if createMemFs && c.renderStaticToDisk {
+			// Writes the dynamic output on memory,
+			// while serve others directly from publishDir
+			publishDir := config.GetString("publishDir")
+			writableFs := afero.NewBasePathFs(afero.NewMemMapFs(), publishDir)
+			publicFs := afero.NewOsFs()
+			fs.Destination = afero.NewCopyOnWriteFs(afero.NewReadOnlyFs(publicFs), writableFs)
+			fs.DestinationStatic = publicFs
 		} else if createMemFs {
 			// Hugo writes the output to memory instead of the disk.
 			fs.Destination = new(afero.MemMapFs)
@@ -397,11 +407,13 @@ func (c *commandeer) loadConfig() error {
 
 			changeDetector.PrepareNew()
 			fs.Destination = hugofs.NewHashingFs(fs.Destination, changeDetector)
+			fs.DestinationStatic = hugofs.NewHashingFs(fs.DestinationStatic, changeDetector)
 			c.changeDetector = changeDetector
 		}
 
 		if c.Cfg.GetBool("logPathWarnings") {
 			fs.Destination = hugofs.NewCreateCountingFs(fs.Destination)
+			fs.DestinationStatic = hugofs.NewCreateCountingFs(fs.DestinationStatic)
 		}
 
 		// To debug hard-to-find path issues.

commands/hugo.go

@@ -652,6 +652,9 @@ func (c *commandeer) copyStaticTo(sourceFs *filesystems.SourceFilesystem) (uint6
 	syncer.ChmodFilter = chmodFilter
 	syncer.SrcFs = fs
 	syncer.DestFs = c.Fs.Destination
+	if c.renderStaticToDisk {
+		syncer.DestFs = c.Fs.DestinationStatic
+	}
 	// Now that we are using a unionFs for the static directories
 	// We can effectively clean the publishDir on initial sync
 	syncer.Delete = c.Cfg.GetBool("cleanDestinationDir")

commands/server.go

@@ -48,15 +48,16 @@ type serverCmd struct {
 	// Can be used to stop the server. Useful in tests
 	stop <-chan bool
 
-	disableLiveReload bool
-	navigateToChanged bool
-	renderToDisk      bool
-	serverAppend      bool
-	serverInterface   string
-	serverPort        int
-	liveReloadPort    int
-	serverWatch       bool
-	noHTTPCache       bool
+	disableLiveReload  bool
+	navigateToChanged  bool
+	renderToDisk       bool
+	renderStaticToDisk bool
+	serverAppend       bool
+	serverInterface    string
+	serverPort         int
+	liveReloadPort     int
+	serverWatch        bool
+	noHTTPCache        bool
 
 	disableFastRender   bool
 	disableBrowserError bool
@@ -101,6 +102,7 @@ of a second, you will be able to save and see your changes nearly instantly.`,
 	cc.cmd.Flags().BoolVar(&cc.renderToDisk, "renderToDisk", false, "render to Destination path (default is render to memory & serve from there)")
 	cc.cmd.Flags().BoolVar(&cc.disableFastRender, "disableFastRender", false, "enables full re-renders on changes")
 	cc.cmd.Flags().BoolVar(&cc.disableBrowserError, "disableBrowserError", false, "do not show build errors in the browser")
+	cc.cmd.Flags().BoolVar(&cc.renderStaticToDisk, "renderStaticToDisk", false, "render static files to disk but dynamic files render to memory.")
 
 	cc.cmd.Flags().String("memstats", "", "log memory usage to this file")
 	cc.cmd.Flags().String("meminterval", "100ms", "interval to poll memory usage (requires --memstats), valid time units are \"ns\", \"us\" (or \"µs\"), \"ms\", \"s\", \"m\", \"h\".")
@@ -141,6 +143,7 @@ func (sc *serverCmd) server(cmd *cobra.Command, args []string) error {
 
 	cfgInit := func(c *commandeer) error {
 		c.Set("renderToMemory", !sc.renderToDisk)
+		c.Set("renderStaticToDisk", sc.renderStaticToDisk)
 		if cmd.Flags().Changed("navigateToChanged") {
 			c.Set("navigateToChanged", sc.navigateToChanged)
 		}
@@ -332,6 +335,8 @@ func (f *fileServer) createEndpoint(i int) (*http.ServeMux, string, string, erro
 	if i == 0 {
 		if f.s.renderToDisk {
 			jww.FEEDBACK.Println("Serving pages from " + absPublishDir)
+		} else if f.s.renderStaticToDisk {
+			jww.FEEDBACK.Println("Serving pages from memory and static files from " + absPublishDir)
 		} else {
 			jww.FEEDBACK.Println("Serving pages from memory")
 		}

commands/static_syncer.go

@@ -56,6 +56,9 @@ func (s *staticSyncer) syncsStaticEvents(staticEvents []fsnotify.Event) error {
 		syncer.ChmodFilter = chmodFilter
 		syncer.SrcFs = sourceFs.Fs
 		syncer.DestFs = c.Fs.Destination
+		if c.renderStaticToDisk {
+			syncer.DestFs = c.Fs.DestinationStatic
+		}
 
 		// prevent spamming the log on changes
 		logger := helpers.NewDistinctErrorLogger()
@@ -101,7 +104,11 @@ func (s *staticSyncer) syncsStaticEvents(staticEvents []fsnotify.Event) error {
 					toRemove := filepath.Join(publishDir, relPath)
 
 					logger.Println("File no longer exists in static dir, removing", toRemove)
-					_ = c.Fs.Destination.RemoveAll(toRemove)
+					if c.renderStaticToDisk {
+						_ = c.Fs.DestinationStatic.RemoveAll(toRemove)
+					} else {
+						_ = c.Fs.Destination.RemoveAll(toRemove)
+					}
 				} else if err == nil {
 					// If file still exists, sync it
 					logger.Println("Syncing", relPath, "to", publishDir)