Print failure when create local file fails

Fix #1645

This only applies when downloading large files. See issue #1645 for more
details

awscli/customizations/s3/s3handler.py

@@ -260,8 +260,9 @@ def _enqueue_range_download_tasks(self, filename, remove_remote_file=False):
         chunksize = find_chunksize(filename.size, self.chunksize)
         num_downloads = int(filename.size / chunksize)
         context = tasks.MultipartDownloadContext(num_downloads)
-        create_file_task = tasks.CreateLocalFileTask(context=context,
-                                                     filename=filename)
+        create_file_task = tasks.CreateLocalFileTask(
+            context=context, filename=filename,
+            result_queue=self.result_queue)
         self.executor.submit(create_file_task)
         self._do_enqueue_range_download_tasks(
             filename=filename, chunksize=chunksize,

awscli/customizations/s3/tasks.py

@@ -263,9 +263,10 @@ def __call__(self):
 
 
 class CreateLocalFileTask(OrderableTask):
-    def __init__(self, context, filename):
+    def __init__(self, context, filename, result_queue):
         self._context = context
         self._filename = filename
+        self._result_queue = result_queue
 
     def __call__(self):
         dirname = os.path.dirname(self._filename.dest)
@@ -284,6 +285,11 @@ def __call__(self):
             with open(self._filename.dest, 'wb'):
                 pass
         except Exception as e:
+            message = print_operation(self._filename, failed=True,
+                                      dryrun=False)
+            message += '\n' + str(e)
+            result = {'message': message, 'error': True}
+            self._result_queue.put(PrintTask(**result))
             self._context.cancel()
         else:
             self._context.announce_file_created()

tests/unit/customizations/s3/test_tasks.py

@@ -15,6 +15,10 @@
 import threading
 import mock
 import socket
+import os
+import tempfile
+import shutil
+from six.moves import queue
 
 from botocore.exceptions import IncompleteReadError
 from botocore.vendored.requests.packages.urllib3.exceptions import \
@@ -326,6 +330,39 @@ def test_print_operation(self):
         self.assertIn(r'e:\foo', message)
 
 
+class TestCreateLocalFileTask(unittest.TestCase):
+    def setUp(self):
+        self.result_queue = queue.Queue()
+        self.tempdir = tempfile.mkdtemp()
+        self.filename = mock.Mock()
+        self.filename.src = 'bucket/key'
+        self.filename.dest = os.path.join(self.tempdir, 'local', 'file')
+        self.filename.operation_name = 'download'
+        self.context = mock.Mock()
+        self.task = CreateLocalFileTask(self.context,
+                                        self.filename,
+                                        self.result_queue)
+
+    def tearDown(self):
+        shutil.rmtree(self.tempdir)
+
+    def test_creates_file_and_announces(self):
+        self.task()
+        self.assertTrue(os.path.isfile(self.filename.dest))
+        self.context.announce_file_created.assert_called_with()
+        self.assertTrue(self.result_queue.empty())
+
+    def test_cancel_command_on_exception(self):
+        # Set destination directory to read-only
+        os.chmod(self.tempdir, 444)
+        self.task()
+        self.assertFalse(os.path.isfile(self.filename.dest))
+        self.context.cancel.assert_called_with()
+        self.assertFalse(self.result_queue.empty())
+        error_message = self.result_queue.get()
+        self.assertIn("download failed", error_message.message)
+
+
 class TestDownloadPartTask(unittest.TestCase):
     def setUp(self):
         self.result_queue = mock.Mock()
@@ -495,7 +532,7 @@ def setUp(self):
     def create_task(self):
         # We don't actually care about the arguments, we just want to test
         # the ordering of the tasks.
-        return CreateLocalFileTask(None, None)
+        return CreateLocalFileTask(None, None, None)
 
     def complete_task(self):
         return CompleteDownloadTask(None, None, None, None, None)