Use f-strings

setup.py

@@ -43,7 +43,7 @@ def run(self):
                 if strict or missing:
                     log.warn('rebuilding js and css failed')
                     if missing:
-                        log.error('missing files: %s' % missing)
+                        log.error(f'missing files: {missing}')
                     raise e
                 else:
                     log.warn('rebuilding js and css failed (not a problem)')
@@ -103,9 +103,9 @@ def run(cmd, **kwargs):
         cmd = shlex.split(cmd)
     cmd_path = shutil.which(cmd[0])
     if not cmd_path:
-        sys.exit("Aborting. Could not find cmd (%s) in path. "
+        sys.exit(f"Aborting. Could not find cmd ({cmd[0]}) in path. "
                  "If command is not expected to be in user's path, "
-                 "use an absolute path." % cmd[0])
+                 "use an absolute path.")
     cmd[0] = cmd_path
     return check_call(cmd, **kwargs)
 
@@ -159,7 +159,7 @@ def run(self):
 
         for t in self.targets:
             if not os.path.exists(t):
-                msg = 'Missing file: %s' % t
+                msg = f'Missing file: {t}'
                 if not has_npm:
                     msg += '\nnpm is required to build a development version'
                 raise ValueError(msg)

tests/app/config_paths_test.py

@@ -10,7 +10,7 @@
 @pytest.fixture
 def voila_config_file_paths_arg():
     path = os.path.join(BASE_DIR, '..', 'configs', 'general')
-    return '--VoilaTest.config_file_paths=[%r]' % path
+    return f'--VoilaTest.config_file_paths=[{path!r}]'
 
 
 def test_config_app(voila_app):

tests/app/cwd_subdir_test.py

@@ -4,12 +4,12 @@
 
 @pytest.fixture
 def cwd_subdir_notebook_url(base_url):
-    return base_url + "voila/render/subdir/cwd_subdir.ipynb"
+    return f"{base_url}/voila/render/subdir/cwd_subdir.ipynb"
 
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 async def test_hello_world(http_server_client, cwd_subdir_notebook_url):

tests/app/execute_cpp_test.py

@@ -6,7 +6,7 @@
 
 @pytest.fixture
 def cpp_file_url(base_url):
-    return base_url + "voila/render/print.xcpp"
+    return f"{base_url}/voila/render/print.xcpp"
 
 
 @pytest.fixture

tests/app/nbextensions_test.py

@@ -19,7 +19,7 @@ def config(app):
 def voila_config_file_paths_arg():
     # we don't want the tests to use any configuration on the system
     path = os.path.abspath(os.path.join(BASE_DIR, '../configs/general'))
-    return '--VoilaTest.config_file_paths=[%r]' % path
+    return f'--VoilaTest.config_file_paths=[{path!r}]'
 
 
 async def test_lists_extension(http_server_client, base_url):

tests/app/no_kernelspec_test.py

@@ -3,12 +3,12 @@
 
 @pytest.fixture
 def non_existing_kernel_notebook(base_url):
-    return base_url + "voila/render/no_kernelspec.ipynb"
+    return f"{base_url}/voila/render/no_kernelspec.ipynb"
 
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}'] + voila_args_extra
 
 
 async def test_non_existing_kernel(http_server_client, non_existing_kernel_notebook):

tests/app/non_existing_kernel_test.py

@@ -3,12 +3,12 @@
 
 @pytest.fixture
 def non_existing_kernel_notebook(base_url):
-    return base_url + "voila/render/non_existing_kernel.ipynb"
+    return f"{base_url}/voila/render/non_existing_kernel.ipynb"
 
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}'] + voila_args_extra
 
 
 async def test_non_existing_kernel(http_server_client, non_existing_kernel_notebook):

tests/app/notebooks_test.py

@@ -4,10 +4,10 @@
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 async def test_other_comms(http_server_client, base_url):
-    response = await http_server_client.fetch(base_url + 'voila/render/other_comms.ipynb')
+    response = await http_server_client.fetch(f'{base_url}/voila/render/other_comms.ipynb')
     html_text = response.body.decode('utf-8')
     assert 'This notebook executed' in html_text

tests/app/serve_directory_test.py

@@ -7,7 +7,7 @@
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 async def test_print(http_server_client, print_notebook_url):

tests/app/template_cli_test.py

@@ -10,7 +10,7 @@
 def voila_args_extra():
     path_test_template = os.path.abspath(os.path.join(BASE_DIR, '../test_template/share/jupyter/voila/templates/test_template/'))
     path_default = os.path.abspath(os.path.join(BASE_DIR, '../../share/jupyter/voila/templates/default'))
-    return ['--template=None', '--VoilaTest.template_paths=[%r, %r]' % (path_test_template, path_default), '--VoilaExecutor.timeout=240']
+    return ['--template=None', f'--VoilaTest.template_paths=[{path_test_template, path_default}, {'--VoilaExecutor.timeout=240'}]'
 
 
 async def test_template_test(http_server_client, base_url):

tests/app/tree_test.py

@@ -4,7 +4,7 @@
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 @pytest.fixture

tests/conftest.py

@@ -14,7 +14,7 @@ def notebook_directory():
 
 @pytest.fixture
 def print_notebook_url(base_url):
-    return base_url + "voila/render/print.ipynb"
+    return f"{base_url}/voila/render/print.ipynb"
 
 
 @pytest.fixture

tests/server/cwd_subdir_test.py

@@ -5,12 +5,12 @@
 
 @pytest.fixture
 def cwd_subdir_notebook_url(base_url):
-    return base_url + "voila/render/subdir/cwd_subdir.ipynb"
+    return f"{base_url}/voila/render/subdir/cwd_subdir.ipynb"
 
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 async def test_hello_world(http_server_client, cwd_subdir_notebook_url):

tests/server/execute_cpp_test.py

@@ -6,7 +6,7 @@
 
 @pytest.fixture
 def cpp_file_url(base_url):
-    return base_url + "voila/render/print.xcpp"
+    return f"{base_url}/voila/render/print.xcpp"
 
 
 @pytest.fixture
@@ -16,7 +16,7 @@ def jupyter_server_args_extra():
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}'] + voila_args_extra
 
 
 @pytest.mark.skipif(not TEST_XEUS_CLING, reason='opt in to avoid having to install xeus-cling')

tests/server/tree_test.py

@@ -4,7 +4,7 @@
 
 @pytest.fixture
 def voila_args(notebook_directory, voila_args_extra):
-    return ['--VoilaTest.root_dir=%r' % notebook_directory, '--VoilaTest.log_level=DEBUG'] + voila_args_extra
+    return [f'--VoilaTest.root_dir={notebook_directory!r}', '--VoilaTest.log_level=DEBUG'] + voila_args_extra
 
 
 @pytest.fixture
@@ -13,7 +13,7 @@ def jupyter_server_args_extra():
 
 
 async def test_tree(http_server_client, base_url):
-    response = await http_server_client.fetch(base_url+'voila/tree')
+    response = await http_server_client.fetch(f'{base_url}voila/tree')
     assert response.code == 200
     text = response.body.decode('utf-8')
     assert 'print.ipynb' in text, 'tree handler should render ipynb files'

voila/app.py

@@ -238,7 +238,7 @@ def display_url(self):
                 url += '/'
         else:
             if self.ip in ('', '0.0.0.0'):
-                ip = "%s" % socket.gethostname()
+                ip = f"{socket.gethostname()}"
             else:
                 ip = self.ip
             url = self._url(ip)
@@ -260,7 +260,7 @@ def _url(self, ip):
         # TODO: https / certfile
         # proto = 'https' if self.certfile else 'http'
         proto = 'http'
-        return "%s://%s:%i%s" % (proto, ip, self.port, self.base_url)
+        return f"{proto}://{ip}:{self.port}{self.base_url}"
 
     config_file_paths = List(
         Unicode(),
@@ -285,7 +285,7 @@ def _config_file_paths_default(self):
     @default('connection_dir_root')
     def _default_connection_dir(self):
         connection_dir = tempfile.gettempdir()
-        self.log.info('Using %s to store connection files' % connection_dir)
+        self.log.info(f'Using {connection_dir} to store connection files')
         return connection_dir
 
     @default('log_level')
@@ -314,7 +314,7 @@ def _default_root_dir(self):
             return getcwd()
 
     def initialize(self, argv=None):
-        self.log.debug("Searching path %s for config files", self.config_file_paths)
+        self.log.debug(f"Searching path {self.config_file_paths} for config files")
         # to make config_file_paths settable via cmd line, we first need to parse it
         super(Voila, self).initialize(argv)
         if len(self.extra_args) == 1:
@@ -326,9 +326,9 @@ def initialize(self, argv=None):
                 elif os.path.isfile(arg):
                     self.notebook_path = arg
                 else:
-                    raise ValueError('argument is neither a file nor a directory: %r' % arg)
+                    raise ValueError(f'argument is neither a file nor a directory: {arg!r}')
         elif len(self.extra_args) != 0:
-            raise ValueError('provided more than 1 argument: %r' % self.extra_args)
+            raise ValueError(f'provided more than 1 argument: {self.extra_args!r}')
 
         # then we load the config
         self.load_config_file('voila', path=self.config_file_paths)
@@ -358,19 +358,19 @@ def setup_template_dirs(self):
         self.log.debug('template paths:\n\t%s', '\n\t'.join(self.template_paths))
         self.log.debug('static paths:\n\t%s', '\n\t'.join(self.static_paths))
         if self.notebook_path and not os.path.exists(self.notebook_path):
-            raise ValueError('Notebook not found: %s' % self.notebook_path)
+            raise ValueError(f'Notebook not found: {self.notebook_path}')
 
     def _handle_signal_stop(self, sig, frame):
-        self.log.info('Handle signal %s.' % sig)
+        self.log.info(f'Handle signal {sig}.')
         self.ioloop.add_callback_from_signal(self.ioloop.stop)
 
     def start(self):
         self.connection_dir = tempfile.mkdtemp(
             prefix='voila_',
             dir=self.connection_dir_root
         )
-        self.log.info('Storing connection files in %s.' % self.connection_dir)
-        self.log.info('Serving static files from %s.' % self.static_root)
+        self.log.info(f'Storing connection files in {self.connection_dir}.')
+        self.log.info(f'Serving static files from {self.static_root}.')
 
         self.kernel_spec_manager = KernelSpecManager(
             parent=self
@@ -424,8 +424,8 @@ def start(self):
         handlers = []
 
         handlers.extend([
-            (url_path_join(self.server_url, r'/api/kernels/%s' % _kernel_id_regex), KernelHandler),
-            (url_path_join(self.server_url, r'/api/kernels/%s/channels' % _kernel_id_regex), ZMQChannelsHandler),
+            (url_path_join(self.server_url, fr'/api/kernels/{_kernel_id_regex}'), KernelHandler),
+            (url_path_join(self.server_url, fr'/api/kernels/{_kernel_id_regex}/channels'), ZMQChannelsHandler),
             (
                 url_path_join(self.server_url, r'/voila/static/(.*)'),
                 MultiStaticFileHandler,
@@ -475,7 +475,7 @@ def start(self):
                 }
             ))
         else:
-            self.log.debug('serving directory: %r', self.root_dir)
+            self.log.debug(f'serving directory: {self.root_dir!r})
             handlers.extend([
                 (self.server_url, VoilaTreeHandler, tree_handler_conf),
                 (url_path_join(self.server_url, r'/voila/tree' + path_regex),
@@ -547,7 +547,7 @@ def launch_browser(self):
         try:
             browser = webbrowser.get(self.browser or None)
         except webbrowser.Error as e:
-            self.log.warning(_('No web browser found: %s.') % e)
+            self.log.warning(_(f'No web browser found: {e}.')
             browser = None
 
         if not browser:

voila/execute.py

@@ -109,7 +109,7 @@ def strip_code_cell_errors(self, cell):
 
         error_outputs = [output for output in outputs if output['output_type'] == 'error']
 
-        error_message = 'There was an error when executing cell [{}]. {}'.format(cell['execution_count'], self.cell_error_instruction)
+        error_message = 'There was an error when executing cell [{cell["execution_count"]}]. {self.cell_error_instruction}'
 
         for output in error_outputs:
             output['ename'] = 'ExecutionError'
@@ -121,7 +121,7 @@ def strip_code_cell_errors(self, cell):
     def show_code_cell_timeout(self, cell):
         """Show a timeout error output in a code cell."""
 
-        timeout_message = 'Cell execution timed out, aborting notebook execution. {}'.format(self.cell_timeout_instruction)
+        timeout_message = f'Cell execution timed out, aborting notebook execution. {self.cell_timeout_instruction}'
 
         output = {'output_type': 'error',
                   'ename': 'TimeoutError',

voila/treehandler.py

@@ -80,7 +80,7 @@ def allowed_content(content):
             url = url_path_join(
                 self.base_url, service, url_escape(path),
             )
-            self.log.debug("Redirecting %s to %s", self.request.path, url)
+            self.log.debug(f"Redirecting {self.request.path} to {url}")
             self.redirect(url)
         else:
             raise web.HTTPError(404)

voila/utils.py

@@ -13,5 +13,5 @@ def get_server_root_dir(settings):
     home = os.path.expanduser('~')
     if root_dir.startswith(home + os.path.sep):
         # collapse $HOME to ~
-        root_dir = '~' + root_dir[len(home):]
+        root_dir = f"~{root_dir[len(home):]}"
     return root_dir