Update QueryOutFileArgument permission logic

This allows the permission mode to be set prior to writing any
content for new created files.

awscli/customizations/arguments.py

@@ -14,6 +14,7 @@
 import re
 
 from awscli.arguments import CustomArgument
+from awscli.compat import compat_open
 import jmespath
 
 
@@ -126,12 +127,18 @@ def save_query(self, parsed, **kwargs):
         """
         if is_parsed_result_successful(parsed):
             contents = jmespath.search(self.query, parsed)
-            with open(self.value, 'w') as fp:
+            with compat_open(
+                    self.value, 'w', access_permissions=self.perm) as fp:
                 # Don't write 'None' to a file -- write ''.
                 if contents is None:
                     fp.write('')
                 else:
                     fp.write(contents)
+                # Even though the file is opened using self.perm permissions,
+                # the file may already exist and as a result, retain it's
+                # preexisting file permissions. The os.chmod is retained here
+                # to preserve behavior of this argument always clobbering
+                # a preexisting file's permissions.
                 os.chmod(self.value, self.perm)
 
 

tests/unit/customizations/test_arguments.py

@@ -144,7 +144,7 @@ def test_saves_query_to_file_as_empty_string_when_none_result(self):
 
     @skip_if_windows("Test not valid on windows.")
     def test_permissions_on_created_file(self):
-        outfile = self.files.create_file('not-empty-test', '')
+        outfile = self.files.full_path('not-empty-test')
         session = mock.Mock()
         arg = QueryOutFileArgument(session, 'foo', 'baz', 'event', 0o600)
         arg.add_to_params({}, outfile)