Enhanced the pipeline to propagate the watching exception to the wisd…

…om server (#26)

Signed-off-by: Clement Escoffier <[email protected]>

core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/mojos/CoffeeScriptCompilerMojo.java

@@ -166,7 +166,7 @@ private void invokeCoffeeScriptCompiler(File input, File out) throws WatchingExc
     public WatchingException build(String message) {
         String[] lines = message.split("\n");
         for (String l : lines) {
-            if (! Strings.isNullOrEmpty(l)) {
+            if (!Strings.isNullOrEmpty(l)) {
                 message = l.trim();
                 break;
             }
@@ -178,7 +178,8 @@ public WatchingException build(String message) {
             String character = matcher.group(3);
             String reason = matcher.group(4);
             File file = new File(path);
-            return new WatchingException(reason, file, Integer.valueOf(line), Integer.valueOf(character), null);
+            return new WatchingException("CoffeeScript Compilation Error: " + reason, file,
+                    Integer.valueOf(line), Integer.valueOf(character), null);
         } else {
             return new WatchingException("CoffeeScript Compilation Error : " + message);
         }

core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/pipeline/Pipeline.java

@@ -19,23 +19,26 @@
  */
 package org.wisdom.maven.pipeline;
 
+import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.filefilter.TrueFileFilter;
 import org.apache.commons.io.monitor.FileAlterationMonitor;
 import org.apache.commons.io.monitor.FileAlterationObserver;
 import org.apache.maven.plugin.Mojo;
+import org.json.simple.JSONObject;
 import org.wisdom.maven.Watcher;
 import org.wisdom.maven.WatchingException;
 import org.wisdom.maven.utils.DefensiveThreadFactory;
 
 import java.io.File;
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * The pipeline is the spine of the watching system of Wisdom.
  * Each Mojo, i.e. Maven Plugin, willing to become a watcher, will be plugged to the pipeline. Registration is made
  * using org.wisdom.maven.pipeline.Watchers#add(org.apache.maven.execution.MavenSession, org.wisdom.maven.Watcher).
- * <p/>
+ * <p>
  * The pipeline is an internal class and should not be used directly. It just delegates the file events to the
  * watchers. So this class holds the file alteration monitor that triggers the reactions of the different mojos.
  */
@@ -47,14 +50,20 @@ public class Pipeline {
     private FileAlterationMonitor watcher;
     private final File baseDir;
 
+    /**
+     * The file used to store a JSON representation of Watching Exceptions happening on a watched event.
+     */
+    private final File error;
+
     private final static String WATCHING_EXCEPTION_MESSAGE = "Watching exception: %s (check log for more details)";
 
 
     /**
      * Creates a new pipeline. Notice that the set of watchers cannot change.
-     * @param mojo the 'run' mojo
+     *
+     * @param mojo    the 'run' mojo
      * @param baseDir the base directory of the watched project
-     * @param list the set of watchers plugged on the pipeline, the order of the list will be the notification order.
+     * @param list    the set of watchers plugged on the pipeline, the order of the list will be the notification order.
      */
     public Pipeline(Mojo mojo, File baseDir, List<? extends Watcher> list) {
         this.mojo = mojo;
@@ -64,6 +73,9 @@ public Pipeline(Mojo mojo, File baseDir, List<? extends Watcher> list) {
         for (Object o : list) {
             watchers.add(new WatcherDelegate(o));
         }
+        File pipelineDirectory = new File(baseDir, "target/pipeline");
+        mojo.getLog().debug("Creating the target/pipeline directory : " + pipelineDirectory.mkdirs());
+        error = new File(pipelineDirectory, "error.json");
     }
 
     /**
@@ -80,6 +92,7 @@ public void shutdown() {
 
     /**
      * Starts the watching.
+     *
      * @return the current pipeline.
      */
     public Pipeline watch() {
@@ -100,9 +113,11 @@ public Pipeline watch() {
 
     /**
      * The FAM has detected a new file. It dispatches this event to the watchers plugged on the current pipeline.
+     *
      * @param file the created file
      */
     public void onFileCreate(File file) {
+        cleanupErrorFile();
         mojo.getLog().info(EMPTY_STRING);
         mojo.getLog().info("The watcher has detected a new file: " + file.getAbsolutePath());
         mojo.getLog().info(EMPTY_STRING);
@@ -116,6 +131,7 @@ public void onFileCreate(File file) {
                     mojo.getLog().debug(watcher + " has thrown an exception while handling the " + file.getName() + EMPTY_STRING +
                             " creation", e);
                     mojo.getLog().error(String.format(WATCHING_EXCEPTION_MESSAGE, e.getMessage()));
+                    createErrorFile(e);
                     continueProcessing = false;
                 }
                 if (!continueProcessing) {
@@ -127,12 +143,52 @@ public void onFileCreate(File file) {
         mojo.getLog().info(EMPTY_STRING);
     }
 
+    /**
+     * Creates the error file storing the information from the given exception in JSON. This file is consumed by the
+     * Wisdom server to generate an error page reporting the watching exception.
+     *
+     * @param e the exception
+     */
+    @SuppressWarnings("unchecked")
+    private void createErrorFile(WatchingException e) {
+        mojo.getLog().debug("Creating error file for '" + e.getMessage() + "' happening at " + e.getLine() + ":" + e
+                .getCharacter() + " of " + e.getFile());
+        JSONObject obj = new JSONObject();
+        obj.put("message", e.getMessage());
+        if (e.getFile() != null) {
+            obj.put("file", e.getFile().getAbsolutePath());
+        }
+        if (e.getLine() != -1) {
+            obj.put("line", e.getLine());
+        }
+        if (e.getCharacter() != -1) {
+            obj.put("character", e.getCharacter());
+        }
+        if (e.getCause() != null) {
+            obj.put("cause", e.getCause().getMessage());
+        }
+        try {
+            FileUtils.writeStringToFile(error, obj.toJSONString(), false);
+        } catch (IOException e1) {
+            mojo.getLog().error("Cannot write the error file", e1);
+        }
+    }
+
+    /**
+     * Method called on each event before the processing, deleting the error file is this file exists.
+     */
+    private void cleanupErrorFile() {
+        FileUtils.deleteQuietly(error);
+    }
+
     /**
      * The FAM has detected a change in a file. It dispatches this event to the watchers plugged on the current
      * pipeline.
+     *
      * @param file the updated file
      */
     public void onFileChange(File file) {
+        cleanupErrorFile();
         mojo.getLog().info(EMPTY_STRING);
         mojo.getLog().info("The watcher has detected a change in " + file.getAbsolutePath());
         mojo.getLog().info(EMPTY_STRING);
@@ -146,6 +202,7 @@ public void onFileChange(File file) {
                     mojo.getLog().debug(watcher + " has thrown an exception while handling the " + file.getName() + EMPTY_STRING +
                             " update", e);
                     mojo.getLog().error(String.format(WATCHING_EXCEPTION_MESSAGE, e.getMessage()));
+                    createErrorFile(e);
                     continueProcessing = false;
                 }
                 if (!continueProcessing) {
@@ -160,9 +217,11 @@ public void onFileChange(File file) {
     /**
      * The FAM has detected a file deletion. It dispatches this event to the watchers plugged on the current
      * pipeline.
+     *
      * @param file the deleted file
      */
     public void onFileDelete(File file) {
+        cleanupErrorFile();
         mojo.getLog().info(EMPTY_STRING);
         mojo.getLog().info("The watcher has detected a deleted file: " + file.getAbsolutePath());
         mojo.getLog().info(EMPTY_STRING);
@@ -176,6 +235,7 @@ public void onFileDelete(File file) {
                     mojo.getLog().debug(watcher + " has thrown an exception while handling the " + file.getName() + EMPTY_STRING +
                             " deletion", e);
                     mojo.getLog().error(String.format(WATCHING_EXCEPTION_MESSAGE, e.getMessage()));
+                    createErrorFile(e);
                     continueProcessing = false;
                 }
                 if (!continueProcessing) {

core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/pipeline/WatcherDelegate.java

@@ -29,7 +29,7 @@
 /**
  * An implementation of watcher using delegation.
  * The invocation are delegate on an object by reflection. This is necessary because the retrieve watchers are not
- * loaded with the same classloader as the run mojo. This comes form the forked lifecycle done by the run mojo.
+ * loaded with the same classloader as the run mojo. This comes from the forked lifecycle done by the run mojo.
  */
 public class WatcherDelegate implements Watcher {
 
@@ -42,10 +42,10 @@ public class WatcherDelegate implements Watcher {
     public WatcherDelegate(Object delegate) {
         this.delegate = delegate;
         try {
-            this.accept = delegate.getClass().getMethod("accept", new Class[] {File.class});
-            this.fileCreated = delegate.getClass().getMethod("fileCreated", new Class[] {File.class});
-            this.fileUpdated = delegate.getClass().getMethod("fileUpdated", new Class[] {File.class});
-            this.fileDeleted = delegate.getClass().getMethod("fileDeleted", new Class[] {File.class});
+            this.accept = delegate.getClass().getMethod("accept", new Class[]{File.class});
+            this.fileCreated = delegate.getClass().getMethod("fileCreated", new Class[]{File.class});
+            this.fileUpdated = delegate.getClass().getMethod("fileUpdated", new Class[]{File.class});
+            this.fileDeleted = delegate.getClass().getMethod("fileDeleted", new Class[]{File.class});
         } catch (NoSuchMethodException e) {
             throw new RuntimeException(e);
         }
@@ -67,18 +67,52 @@ public boolean fileCreated(File file) throws WatchingException {
         try {
             return (Boolean) fileCreated.invoke(delegate, file);
         } catch (InvocationTargetException e) { //NOSONAR
-            throw new WatchingException(e.getTargetException().getMessage(), file, e.getTargetException());
+            throw createWatchingException(e, file);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
     }
 
+    /**
+     * Even {@link org.wisdom.maven.WatchingException} cannot be used directly, so we need to use reflection to
+     * recreate the exception with the same content.
+     * <p>
+     * This method checks if the cause of the {@link java.lang.reflect
+     * .InvocationTargetException} is a {@link org.wisdom.maven.WatchingException},
+     * in this case if create an exception with the same content. Otherwise it creates a new {@link org.wisdom.maven
+     * .WatchingException} from the given exception's cause.
+     *
+     * @param exception the invocation target exception caught by the delegate
+     * @param file      the file having thrown the exception (the processed file).
+     * @return a Watching Exception containing the content from the given exception if possible or a new exception
+     * from the {@literal exception}'s cause.
+     */
+    public static WatchingException createWatchingException(InvocationTargetException exception, File file) {
+        Throwable cause = exception.getTargetException();
+        if (WatchingException.class.getName().equals(exception.getTargetException().getClass().getName())) {
+            try {
+                Method line = cause.getClass().getMethod("getLine");
+                Method character = cause.getClass().getMethod("getCharacter");
+                Method source = cause.getClass().getMethod("getFile");
+
+                return new WatchingException(cause.getMessage(), (File) source.invoke(cause),
+                        (Integer) line.invoke(cause),
+                        (Integer) character.invoke(cause),
+                        cause.getCause());
+            } catch (InvocationTargetException | NoSuchMethodException | IllegalAccessException e) {
+                throw new IllegalArgumentException("Cannot create the watching exception from " + cause);
+            }
+        } else {
+            return new WatchingException(cause.getMessage(), file, cause);
+        }
+    }
+
     @Override
     public boolean fileUpdated(File file) throws WatchingException {
         try {
             return (Boolean) fileUpdated.invoke(delegate, file);
         } catch (InvocationTargetException e) { //NOSONAR
-            throw new WatchingException(e.getTargetException().getMessage(), file, e.getTargetException());
+            throw createWatchingException(e, file);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
@@ -89,7 +123,7 @@ public boolean fileDeleted(File file) throws WatchingException {
         try {
             return (Boolean) fileDeleted.invoke(delegate, file);
         } catch (InvocationTargetException e) { //NOSONAR
-            throw new WatchingException(e.getTargetException().getMessage(), file, e.getTargetException());
+            throw createWatchingException(e, file);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }

core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/utils/CompilerExecutor.java

@@ -116,7 +116,8 @@ public static WatchingException build(AbstractWisdomMojo mojo, Throwable excepti
             String character = matcher.group(3);
             String reason = matcher.group(4);
             File file = new File(path);
-            return new WatchingException(reason, file, Integer.valueOf(line), Integer.valueOf(character), null);
+            return new WatchingException("Java Compilation Error: " + reason, file, Integer.valueOf(line),
+                    Integer.valueOf(character), null);
         } else {
             return new WatchingException("Java Compilation Error", exception);
         }

core/wisdom-maven-plugin/src/test/java/org/wisdom/maven/pipeline/PipelineTest.java

@@ -50,13 +50,14 @@ public class PipelineTest {
     Pipeline pipeline;
     private SpyWatcher textWatcher;
     private SpyWatcher mdWatcher;
+    private Mojo mojo;
 
     @Before
     public void setUp() throws IOException {
         FileUtils.forceMkdir(SOURCES);
         textWatcher = new SpyWatcher(SOURCES, "txt");
         mdWatcher = new SpyWatcher(SOURCES, "md");
-        Mojo mojo = mock(Mojo.class);
+        mojo = mock(Mojo.class);
         Log log = mock(Log.class);
         when(mojo.getLog()).thenReturn(log);
         pipeline = new Pipeline(mojo, FAKE, Arrays.asList(textWatcher, mdWatcher));
@@ -112,6 +113,28 @@ public void testAdditionUpdateAndDeleteOfSubFiles() throws IOException {
         assertThat(mdWatcher.deleted).containsExactly("touch.md");
     }
 
+    @Test
+    public void testWatchingException() throws IOException {
+        pipeline.shutdown();
+
+        BadWatcher bad = new BadWatcher(SOURCES, "md");
+        pipeline = new Pipeline(mojo, FAKE, Arrays.asList(bad));
+        pipeline.watch();
+
+        File dir = new File(SOURCES, "foo");
+        dir.mkdirs();
+        File md = new File(SOURCES, "foo/touch.md");
+        md.createNewFile();
+        assertThat(md.isFile()).isTrue();
+        waitPullPeriod();
+
+        // Check that the error file was created.
+        File error = new File(FAKE, "target/pipeline/error.json");
+        assertThat(error).exists();
+        assertThat(FileUtils.readFileToString(error)).contains("10").contains("11").contains("touch.md").contains
+                ("bad");
+    }
+
     private void waitPullPeriod() {
         try {
             Thread.sleep(2500);
@@ -156,4 +179,21 @@ public boolean fileDeleted(File file) throws WatchingException {
             return true;
         }
     }
+
+    private class BadWatcher extends SpyWatcher {
+
+        public BadWatcher(File root, String extension) {
+            super(root, extension);
+        }
+
+        @Override
+        public boolean fileCreated(File file) throws WatchingException {
+            throw new WatchingException("Bad bad bad", file, 10, 11, null);
+        }
+
+        @Override
+        public boolean fileUpdated(File file) throws WatchingException {
+            throw new WatchingException("Bad bad bad", file, 10, 11, null);
+        }
+    }
 }