Remove unused render_template_to_file method

In a filesystem access code audit I found the method render_template_to_file is not used in the code. This patch removes it and it's tests.

Change-Id: I0264349176763f9aa4a87750aca270a6acd2c529

designate/tests/unit/test_utils.py

@@ -213,44 +213,6 @@ class TestUtils(oslotest.base.BaseTestCase):
 
         self.assertEqual('Hello World', result)
 
-    @mock.patch('builtins.open', new_callable=mock.mock_open)
-    @mock.patch('os.path.exists')
-    def test_render_template_to_file(self, mock_exists, mock_open):
-        mock_exists.return_value = True
-
-        output_path = '/tmp/designate/resources/templates/hello.jinja2'
-
-        template = jinja2.Template('Hello {{name}}')
-
-        utils.render_template_to_file(
-            template, makedirs=False, output_path=output_path, name='World'
-        )
-
-        mock_open.assert_called_once_with(output_path, 'w')
-        mock_open().write.assert_called_once_with('Hello World')
-
-    @mock.patch('builtins.open', new_callable=mock.mock_open)
-    @mock.patch('os.path.exists')
-    @mock.patch('os.makedirs')
-    def test_render_template_to_file_with_makedirs(self, mock_makedirs,
-                                                   mock_exists,
-                                                   mock_open):
-        mock_exists.return_value = False
-
-        output_path = '/tmp/designate/resources/templates/hello.jinja2'
-
-        template = jinja2.Template('Hello {{name}}')
-
-        utils.render_template_to_file(
-            template, makedirs=True, output_path=output_path, name='World'
-        )
-
-        mock_makedirs.assert_called_once_with(
-            '/tmp/designate/resources/templates'
-        )
-        mock_open.assert_called_once_with(output_path, 'w')
-        mock_open().write.assert_called_once_with('Hello World')
-
     @mock.patch.object(timeutils, 'utcnow_ts')
     def test_increment_serial_lower_than_ts(self, mock_utcnow_ts):
         mock_utcnow_ts.return_value = 1561698354

designate/utils.py

@@ -110,21 +110,6 @@ def render_template(template, **template_context):
     return template.render(**template_context)
 
 
-def render_template_to_file(template_name, output_path, makedirs=True,
-                            **template_context):
-    output_folder = os.path.dirname(output_path)
-
-    # Create the output folder tree if necessary
-    if makedirs and not os.path.exists(output_folder):
-        os.makedirs(output_folder)
-
-    # Render the template
-    content = render_template(template_name, **template_context)
-
-    with open(output_path, 'w') as output_fh:
-        output_fh.write(content)
-
-
 def execute(*cmd, **kw):
     """Execute a command in a subprocess, blocking.
     """