Fix reader of slim. (#2477)

* Fix reader of slim.

* Remove unused comments.

PaddleSlim/reader.py

@@ -133,33 +133,36 @@ def _reader_creator(file_list,
                     data_dir=DATA_DIR,
                     batch_size=1):
     def reader():
-        with open(file_list) as flist:
-            full_lines = [line.strip() for line in flist]
-            if shuffle:
-                np.random.shuffle(full_lines)
-            if mode == 'train' and os.getenv('PADDLE_TRAINING_ROLE'):
-                # distributed mode if the env var `PADDLE_TRAINING_ROLE` exits
-                trainer_id = int(os.getenv("PADDLE_TRAINER_ID", "0"))
-                trainer_count = int(os.getenv("PADDLE_TRAINERS", "1"))
-                per_node_lines = len(full_lines) // trainer_count
-                lines = full_lines[trainer_id * per_node_lines:(trainer_id + 1)
-                                   * per_node_lines]
-                print(
-                    "read images from %d, length: %d, lines length: %d, total: %d"
-                    % (trainer_id * per_node_lines, per_node_lines, len(lines),
-                       len(full_lines)))
-            else:
-                lines = full_lines
-
-            for line in lines:
-                if mode == 'train' or mode == 'val':
-                    img_path, label = line.split()
-                    #                    img_path = img_path.replace("JPEG", "jpeg")
-                    img_path = os.path.join(data_dir, img_path)
-                    yield img_path, int(label)
-                elif mode == 'test':
-                    img_path = os.path.join(data_dir, line)
-                    yield [img_path]
+        try:
+            with open(file_list) as flist:
+                full_lines = [line.strip() for line in flist]
+                if shuffle:
+                    np.random.shuffle(full_lines)
+                if mode == 'train' and os.getenv('PADDLE_TRAINING_ROLE'):
+                    # distributed mode if the env var `PADDLE_TRAINING_ROLE` exits
+                    trainer_id = int(os.getenv("PADDLE_TRAINER_ID", "0"))
+                    trainer_count = int(os.getenv("PADDLE_TRAINERS", "1"))
+                    per_node_lines = len(full_lines) // trainer_count
+                    lines = full_lines[trainer_id * per_node_lines:(
+                        trainer_id + 1) * per_node_lines]
+                    print(
+                        "read images from %d, length: %d, lines length: %d, total: %d"
+                        % (trainer_id * per_node_lines, per_node_lines,
+                           len(lines), len(full_lines)))
+                else:
+                    lines = full_lines
+
+                for line in lines:
+                    if mode == 'train' or mode == 'val':
+                        img_path, label = line.split()
+                        img_path = os.path.join(data_dir, img_path)
+                        yield img_path, int(label)
+                    elif mode == 'test':
+                        img_path = os.path.join(data_dir, line)
+                        yield [img_path]
+        except Exception as e:
+            print("Reader failed!\n{}".format(str(e)))
+            os._exit(1)
 
     mapper = functools.partial(
         process_image, mode=mode, color_jitter=color_jitter, rotate=rotate)