From f5698fbd84e3a1e674309b9dc0beee2ecfa10967 Mon Sep 17 00:00:00 2001
From: Leandro Ezequiel Barrios <lbarrios@mulesoft.com>
Date: Thu, 5 Sep 2024 15:56:02 -0300
Subject: [PATCH] Fixed

---
 .../TracingConfigurationFileWatcher.java      | 53 ++++++++++---------
 ...FileSpanExporterConfigurationTestCase.java |  2 +-
 2 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/modules/tracing/mule-tracer-common/src/main/java/org/mule/runtime/tracer/common/watcher/TracingConfigurationFileWatcher.java b/modules/tracing/mule-tracer-common/src/main/java/org/mule/runtime/tracer/common/watcher/TracingConfigurationFileWatcher.java
index beb6e0601a04..70f07aa3b93c 100644
--- a/modules/tracing/mule-tracer-common/src/main/java/org/mule/runtime/tracer/common/watcher/TracingConfigurationFileWatcher.java
+++ b/modules/tracing/mule-tracer-common/src/main/java/org/mule/runtime/tracer/common/watcher/TracingConfigurationFileWatcher.java
@@ -6,11 +6,19 @@
  */
 package org.mule.runtime.tracer.common.watcher;
 
+import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
 import static org.mule.runtime.tracer.exporter.config.api.OpenTelemetrySpanExporterConfigurationProperties.MULE_OPEN_TELEMETRY_EXPORTER_CONFIGURATION_WATCHER_DEFAULT_DELAY_PROPERTY;
 
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.Path;
+import java.nio.file.WatchEvent;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
+import java.util.concurrent.TimeUnit;
 
 import org.slf4j.Logger;
 
@@ -23,44 +31,42 @@ public class TracingConfigurationFileWatcher extends Thread {
   public final long DEFAULT_DELAY = Long
       .getLong(MULE_OPEN_TELEMETRY_EXPORTER_CONFIGURATION_WATCHER_DEFAULT_DELAY_PROPERTY,
                60000l);
-  private final String filename;
   private final Runnable doOnChange;
+  private final File file;
+  private final WatchService watchService;
 
   protected long delay = DEFAULT_DELAY;
-  private final File file;
-  private long lastModified;
-  private boolean warnedAlready;
 
   public TracingConfigurationFileWatcher(String filename, Runnable doOnChange) {
     super("FileSpanExporterConfigurationWatcher");
-    this.filename = filename;
     this.file = new File(filename);
     this.doOnChange = doOnChange;
-    this.lastModified = file.lastModified();
+
+    try {
+      this.watchService = FileSystems.getDefault().newWatchService();
+      file.toPath().getParent().register(watchService, ENTRY_MODIFY);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+
     this.setDaemon(true);
   }
 
-  protected void checkAndConfigure() {
-    boolean fileExists;
-    try {
-      fileExists = file.exists();
-    } catch (SecurityException var4) {
-      LOGGER.warn("The tracing config file " + filename + " was possibly removed.");
-      this.interrupt();
+  protected void checkAndConfigure() throws InterruptedException {
+    WatchKey key = watchService.poll(delay, TimeUnit.MILLISECONDS);
+    if (key == null) {
       return;
     }
 
-    if (fileExists) {
-      long fileLastMod = file.lastModified();
-      if (fileLastMod > lastModified) {
-        this.lastModified = fileLastMod;
-        this.doOnChange();
-        this.warnedAlready = false;
+    for (WatchEvent<?> event : key.pollEvents()) {
+      if (ENTRY_MODIFY.equals(event.kind())) {
+        Path changedFile = (Path) event.context();
+        if (changedFile.equals(file.toPath().getFileName())) {
+          this.doOnChange();
+        }
       }
-    } else if (!this.warnedAlready) {
-      LOGGER.warn("Configuration for file exporter was not found. It was possibly removed.");
-      this.warnedAlready = true;
     }
+    key.reset();
   }
 
   @Override
@@ -68,8 +74,7 @@ public void run() {
     while (!interrupted()) {
       try {
         checkAndConfigure();
-        sleep(delay);
-      } catch (InterruptedException var2) {
+      } catch (InterruptedException ignored) {
         return;
       }
     }
diff --git a/modules/tracing/mule-tracer-exporter-configuration-impl/src/test/java/org/mule/runtime/tracer/exporter/config/impl/FileSpanExporterConfigurationTestCase.java b/modules/tracing/mule-tracer-exporter-configuration-impl/src/test/java/org/mule/runtime/tracer/exporter/config/impl/FileSpanExporterConfigurationTestCase.java
index 69db362e1835..9e64e4f90030 100644
--- a/modules/tracing/mule-tracer-exporter-configuration-impl/src/test/java/org/mule/runtime/tracer/exporter/config/impl/FileSpanExporterConfigurationTestCase.java
+++ b/modules/tracing/mule-tracer-exporter-configuration-impl/src/test/java/org/mule/runtime/tracer/exporter/config/impl/FileSpanExporterConfigurationTestCase.java
@@ -183,7 +183,7 @@ public void whenValueCorrespondingToPathGetAbsoluteValue() {
     assertThat(keyFileLocationPath.isAbsolute(), is(TRUE));
   }
 
-  @Test @Ignore("To be fixed in W-16676258")
+  @Test
   public void configurationFileChanged() throws Exception {
     File file = createTempFile("tracing", "test");
     Path testFile = get(file.getPath());