change download log format (#21290)

* change download log formate; test=develop

* add unittest for data download; test=develop

* remove cache before download; test=develop

python/paddle/dataset/common.py

@@ -79,14 +79,15 @@ def download(url, module_name, md5sum, save_name=None):
     retry_limit = 3
     while not (os.path.exists(filename) and md5file(filename) == md5sum):
         if os.path.exists(filename):
-            sys.stderr.write("file %s  md5 %s" % (md5file(filename), md5sum))
+            sys.stderr.write("file %s  md5 %s\n" % (md5file(filename), md5sum))
         if retry < retry_limit:
             retry += 1
         else:
             raise RuntimeError("Cannot download {0} within retry limit {1}".
                                format(url, retry_limit))
-        sys.stderr.write("Cache file %s not found, downloading %s" %
+        sys.stderr.write("Cache file %s not found, downloading %s \n" %
                          (filename, url))
+        sys.stderr.write("Begin to download\n")
         r = requests.get(url, stream=True)
         total_length = r.headers.get('content-length')
 
@@ -95,18 +96,20 @@ def download(url, module_name, md5sum, save_name=None):
                 shutil.copyfileobj(r.raw, f)
         else:
             with open(filename, 'wb') as f:
-                dl = 0
+                chunk_size = 4096
                 total_length = int(total_length)
-                for data in r.iter_content(chunk_size=4096):
+                total_iter = total_length / chunk_size + 1
+                log_interval = total_iter / 20 if total_iter > 20 else 1
+                log_index = 0
+                for data in r.iter_content(chunk_size=chunk_size):
                     if six.PY2:
                         data = six.b(data)
-                    dl += len(data)
                     f.write(data)
-                    done = int(50 * dl / total_length)
-                    sys.stderr.write("\r[%s%s]" % ('=' * done,
-                                                   ' ' * (50 - done)))
+                    log_index += 1
+                    if log_index % log_interval == 0:
+                        sys.stderr.write(".")
                     sys.stdout.flush()
-    sys.stderr.write("\n")
+    sys.stderr.write("\nDownload finished\n")
     sys.stdout.flush()
     return filename
 

python/paddle/fluid/tests/unittests/test_dataset_download.py

@@ -0,0 +1,46 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import unittest
+from paddle.dataset.common import download, DATA_HOME, md5file
+
+
+class TestDataSetDownload(unittest.TestCase):
+    def setUp(self):
+        flower_path = DATA_HOME + "/flowers/imagelabels.mat"
+
+        if os.path.exists(flower_path):
+            os.remove(flower_path)
+
+    def test_download_url(self):
+        LABEL_URL = 'http://paddlemodels.bj.bcebos.com/flowers/imagelabels.mat'
+        LABEL_MD5 = 'e0620be6f572b9609742df49c70aed4d'
+
+        catch_exp = False
+        try:
+            download(LABEL_URL, 'flowers', LABEL_MD5)
+        except Exception as e:
+            catch_exp = True
+
+        self.assertTrue(catch_exp == False)
+
+        file_path = DATA_HOME + "/flowers/imagelabels.mat"
+
+        self.assertTrue(os.path.exists(file_path))
+        self.assertTrue(md5file(file_path), LABEL_MD5)
+
+
+if __name__ == '__main__':
+    unittest.main()