✨ Add support for symlinks in FileWatcher

This commit allows using symlinks for SSL certificate hot reloading.
TAKETODAY · Feb 22, 2025 · 131b1d4 · 131b1d4
1 parent ad7f7b2
commit 131b1d4
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Showing 2 changed files with 41 additions and 3 deletions.
diff --git a/today-framework/src/main/java/infra/annotation/config/ssl/FileWatcher.java b/today-framework/src/main/java/infra/annotation/config/ssl/FileWatcher.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2024 the original author or authors.
+ * Copyright 2017 - 2025 the original author or authors.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -91,14 +91,26 @@ void watch(Set<Path> paths, Runnable action) {
           this.thread = new WatcherThread();
           this.thread.start();
         }
-        this.thread.register(new Registration(paths, action));
+        Set<Path> actualPaths = new HashSet<>();
+        for (Path path : paths) {
+          actualPaths.add(resolveSymlinkIfNecessary(path));
+        }
+        this.thread.register(new Registration(actualPaths, action));
       }
       catch (IOException ex) {
         throw new UncheckedIOException("Failed to register paths for watching: " + paths, ex);
       }
     }
   }
 
+  private static Path resolveSymlinkIfNecessary(Path path) throws IOException {
+    if (Files.isSymbolicLink(path)) {
+      Path target = Files.readSymbolicLink(path);
+      return resolveSymlinkIfNecessary(target);
+    }
+    return path;
+  }
+
   public void destroy() throws IOException {
     synchronized(this.lock) {
       if (this.thread != null) {

diff --git a/today-framework/src/test/java/infra/annotation/config/ssl/FileWatcherTests.java b/today-framework/src/test/java/infra/annotation/config/ssl/FileWatcherTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2024 the original author or authors.
+ * Copyright 2017 - 2025 the original author or authors.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -94,6 +94,32 @@ void shouldWatchFile(@TempDir Path tempDir) throws Exception {
     callback.expectChanges();
   }
 
+  @Test
+  void shouldFollowSymlink(@TempDir Path tempDir) throws Exception {
+    Path realFile = tempDir.resolve("realFile.txt");
+    Path symLink = tempDir.resolve("symlink.txt");
+    Files.createFile(realFile);
+    Files.createSymbolicLink(symLink, realFile);
+    WaitingCallback callback = new WaitingCallback();
+    this.fileWatcher.watch(Set.of(symLink), callback);
+    Files.writeString(realFile, "Some content");
+    callback.expectChanges();
+  }
+
+  @Test
+  void shouldFollowSymlinkRecursively(@TempDir Path tempDir) throws Exception {
+    Path realFile = tempDir.resolve("realFile.txt");
+    Path symLink = tempDir.resolve("symlink.txt");
+    Path symLink2 = tempDir.resolve("symlink2.txt");
+    Files.createFile(realFile);
+    Files.createSymbolicLink(symLink, symLink2);
+    Files.createSymbolicLink(symLink2, realFile);
+    WaitingCallback callback = new WaitingCallback();
+    this.fileWatcher.watch(Set.of(symLink), callback);
+    Files.writeString(realFile, "Some content");
+    callback.expectChanges();
+  }
+
   @Test
   void shouldIgnoreNotWatchedFiles(@TempDir Path tempDir) throws Exception {
     Path watchedFile = tempDir.resolve("watched.txt");