Add an option to hard link files from static/ instead of copying. (#723)

* Add hard_link_static config option.

* Copy or hardlink file depending on an argument.

Modify the call sites for `copy_file` to account for the extra argument.

* Plug the config setting through to copy_file.

Don't apply the config option to theme's static directory.

* Update documentation.

* Backticks make no sense in this comment.

* Addressing PR comments.

* Be consistent with argument naming.

components/config/src/config.rs

@@ -106,6 +106,8 @@ pub struct Config {
     pub generate_rss: bool,
     /// The number of articles to include in the RSS feed. Defaults to including all items.
     pub rss_limit: Option<usize>,
+    /// If set, files from static/ will be hardlinked instead of copied to the output dir.
+    pub hard_link_static: bool,
 
     pub taxonomies: Vec<Taxonomy>,
 
@@ -280,6 +282,7 @@ impl Default for Config {
             languages: Vec::new(),
             generate_rss: false,
             rss_limit: None,
+            hard_link_static: false,
             taxonomies: Vec::new(),
             compile_sass: false,
             check_external_links: false,

components/site/src/lib.rs

@@ -597,11 +597,12 @@ impl Site {
             copy_directory(
                 &self.base_path.join("themes").join(theme).join("static"),
                 &self.output_path,
+                false
             )?;
         }
         // We're fine with missing static folders
         if self.static_path.exists() {
-            copy_directory(&self.static_path, &self.output_path)?;
+            copy_directory(&self.static_path, &self.output_path, self.config.hard_link_static)?;
         }
 
         Ok(())

components/utils/src/fs.rs

@@ -95,7 +95,7 @@ pub fn find_related_assets(path: &Path) -> Vec<PathBuf> {
 
 /// Copy a file but takes into account where to start the copy as
 /// there might be folders we need to create on the way
-pub fn copy_file(src: &Path, dest: &PathBuf, base_path: &PathBuf) -> Result<()> {
+pub fn copy_file(src: &Path, dest: &PathBuf, base_path: &PathBuf, hard_link: bool) -> Result<()> {
     let relative_path = src.strip_prefix(base_path).unwrap();
     let target_path = dest.join(relative_path);
 
@@ -103,11 +103,15 @@ pub fn copy_file(src: &Path, dest: &PathBuf, base_path: &PathBuf) -> Result<()>
         create_dir_all(parent_directory)?;
     }
 
-    copy(src, target_path)?;
+    if hard_link {
+        std::fs::hard_link(src, target_path)?
+    } else {
+        copy(src, target_path)?;
+    }
     Ok(())
 }
 
-pub fn copy_directory(src: &PathBuf, dest: &PathBuf) -> Result<()> {
+pub fn copy_directory(src: &PathBuf, dest: &PathBuf, hard_link: bool) -> Result<()> {
     for entry in WalkDir::new(src).into_iter().filter_map(std::result::Result::ok) {
         let relative_path = entry.path().strip_prefix(src).unwrap();
         let target_path = dest.join(relative_path);
@@ -117,7 +121,7 @@ pub fn copy_directory(src: &PathBuf, dest: &PathBuf) -> Result<()> {
                 create_directory(&target_path)?;
             }
         } else {
-            copy_file(entry.path(), dest, src)?;
+            copy_file(entry.path(), dest, src, hard_link)?;
         }
     }
     Ok(())

docs/content/documentation/getting-started/configuration.md

@@ -41,6 +41,12 @@ generate_rss = false
 # not set (the default).
 # rss_limit = 20
 
+# Whether to copy or hardlink files in static/ directory. Useful for sites
+# whose static files are large. Note that for this to work, both static/ and
+# output directory need to be on the same filesystem. Also, theme's static/
+# files are always copies, regardles of this setting. False by default.
+# hard_link_static = false
+
 # The taxonomies to be rendered for that site and their configuration
 # Example:
 #     taxonomies = [

docs/content/documentation/getting-started/directory-structure.md

@@ -38,6 +38,8 @@ The directory structure of the `sass` folder will be preserved when copying over
 
 ## `static`
 Contains any kind of files. All the files/folders in the `static` folder will be copied as-is in the output directory.
+If your static files are large you can configure Zola to [hard link](https://en.wikipedia.org/wiki/Hard_link) them
+instead of copying by setting `hard_link_static = true` in the config file.
 
 ## `templates`
 Contains all the [Tera](https://tera.netlify.com) templates that will be used to render this site.

src/cmd/serve.rs

@@ -325,7 +325,7 @@ pub fn serve(
         } else {
             rebuild_done_handling(
                 &broadcaster,
-                copy_file(&path, &site.output_path, &site.static_path),
+                copy_file(&path, &site.output_path, &site.static_path, site.config.hard_link_static),
                 &partial_path.to_string_lossy(),
             );
         }