Notify user when broken symlinks are encountered

You will now see an error message shown as well as a non zero
RC:

  $ aws s3 sync anotherdir/ s3://jamesls-test-sync/
  [Errno 2] No such file or directory: '/private/tmp/symlnk/anotherdir/z-badsylmink'

  $ echo $?
  1

There is potential to add something like a ``--skip-bad-symlinks``
option, but the default behavior is to let the user know that we've hit
a bad symlink.  Fies aws#425 and aws#487.

CHANGELOG.rst

@@ -12,6 +12,9 @@ Next Release (TBD)
   (issue 494 <https://github.com/aws/aws-cli/issues/494>`__)
 * Fix issue with ``--associate-public-ip-address`` when a ``--subnet-id``
   is provided `(issue 501 <https://github.com/aws/aws-cli/issues/501>`__)
+* Fix issue with symlinks silently failing during ``s3 sync/cp``
+  (`issue 425 <https://github.com/aws/aws-cli/issues/425>`__
+   and `issue 487 <https://github.com/aws/aws-cli/issues/487>`__)
 
 
 1.2.5

awscli/customizations/s3/executer.py

@@ -144,6 +144,7 @@ def __init__(self, result_queue, done, quiet, interrupt, timeout):
         self._num_parts = 0
         self._file_count = 0
         self._lock = threading.Lock()
+        self._needs_newline = False
 
         self._total_parts = 0
         self._total_files = '...'
@@ -179,6 +180,8 @@ def run(self):
             except Queue.Empty:
                 pass
             if self._done.isSet():
+                if self._needs_newline:
+                    sys.stdout.write('\n')
                 break
 
     def _process_print_task(self, print_task):
@@ -226,4 +229,5 @@ def _process_print_task(self, print_task):
             final_str += prog_str
         if not self._quiet:
             uni_print(final_str)
+            self._needs_newline = not final_str.endswith('\n')
             sys.stdout.flush()

awscli/customizations/s3/s3handler.py

@@ -80,10 +80,9 @@ def call(self, files):
             self.result_queue.join()
 
         except Exception as e:
-            LOGGER.error('Exception caught during task execution: %s',
-                          str(e))
-            # Log the traceback at DEBUG level.
-            LOGGER.debug(str(e), exc_info=True)
+            LOGGER.debug('Exception caught during task execution: %s',
+                         str(e), exc_info=True)
+            self.result_queue.put({'message': str(e), 'error': True})
         except KeyboardInterrupt:
             self.interrupt.set()
             self.result_queue.put({'message': "Cleaning up. Please wait...",

tests/integration/customizations/s3/test_plugin.py

@@ -362,6 +362,23 @@ def test_sync_with_delete_option_with_same_prefix(self):
         self.assertEqual('', p.stdout)
 
 
+class TestBadSymlinks(BaseS3CLICommand):
+    def test_bad_symlink_stops_sync_process(self):
+        bucket_name = self.create_bucket()
+        nested_dir = os.path.join(self.files.rootdir, 'realfiles')
+        os.mkdir(nested_dir)
+        full_path = self.files.create_file(os.path.join(nested_dir, 'foo.txt'),
+                                           contents='foo.txt contents')
+        symlink_dir = os.path.join(self.files.rootdir, 'symlinkdir')
+        os.mkdir(symlink_dir)
+        os.symlink(full_path, os.path.join(symlink_dir, 'a-goodsymlink'))
+        os.symlink('non-existent-file', os.path.join(symlink_dir, 'b-badsymlink'))
+        os.symlink(full_path, os.path.join(symlink_dir, 'c-goodsymlink'))
+        p = aws('s3 sync %s s3://%s/' % (symlink_dir, bucket_name))
+        self.assertEqual(p.rc, 1, p.stdout)
+        self.assertIn('[Errno 2] No such file or directory', p.stdout)
+
+
 class TestUnicode(BaseS3CLICommand):
     """
     The purpose of these tests are to ensure that the commands can handle