apply pyupgrade fixes via ruff

ruff check --fix --select UP

examples/postgres/hub/jupyterhub_config.py

@@ -25,6 +25,4 @@ import os
 
 pg_pass = os.getenv('POSTGRES_ENV_JPY_PSQL_PASSWORD')
 pg_host = os.getenv('POSTGRES_PORT_5432_TCP_ADDR')
-c.JupyterHub.db_url = 'postgresql://jupyterhub:{}@{}:5432/jupyterhub'.format(
-    pg_pass, pg_host
-)
+c.JupyterHub.db_url = f'postgresql://jupyterhub:{pg_pass}@{pg_host}:5432/jupyterhub'

examples/spawn-form/jupyterhub_config.py

@@ -11,7 +11,7 @@ c = get_config()  # noqa
 class DemoFormSpawner(LocalProcessSpawner):
     def _options_form_default(self):
         default_env = "YOURNAME=%s\n" % self.user.name
-        return """
+        return f"""
         <div class="form-group">
             <label for="args">Extra notebook CLI arguments</label>
             <input name="args" class="form-control"
@@ -19,11 +19,9 @@ class DemoFormSpawner(LocalProcessSpawner):
         </div>
         <div class="form-group">
             <label for="env">Environment variables (one per line)</label>
-            <textarea class="form-control" name="env">{env}</textarea>
+            <textarea class="form-control" name="env">{default_env}</textarea>
         </div>
-        """.format(
-            env=default_env
-        )
+        """
 
     def options_from_form(self, formdata):
         options = {}

jupyterhub/alembic/versions/99a28a4418e1_user_created.py

@@ -29,11 +29,10 @@ def upgrade():
     # fill created date with current time
     now = utcnow()
     c.execute(
-        """
+        f"""
         UPDATE users
-        SET created='%s'
+        SET created='{now}'
         """
-        % (now,)
     )
 
     tables = sa.inspect(c.engine).get_table_names()
@@ -42,12 +41,11 @@ def upgrade():
         op.add_column('spawners', sa.Column('started', sa.DateTime, nullable=True))
         # fill started value with now for running servers
         c.execute(
-            """
+            f"""
             UPDATE spawners
-            SET started='%s'
+            SET started='{now}'
             WHERE server_id IS NOT NULL
             """
-            % (now,)
         )
 
 

jupyterhub/apihandlers/base.py

@@ -40,7 +40,7 @@ class APIHandler(BaseHandler):
         return 'application/json'
 
     @property
-    @lru_cache()
+    @lru_cache
     def accepts_pagination(self):
         """Return whether the client accepts the pagination preview media type"""
         accept_header = self.request.headers.get("Accept", "")
@@ -460,8 +460,7 @@ class APIHandler(BaseHandler):
             if not isinstance(value, model_types[key]):
                 raise web.HTTPError(
                     400,
-                    "%s.%s must be %s, not: %r"
-                    % (name, key, model_types[key], type(value)),
+                    f"{name}.{key} must be {model_types[key]}, not: {type(value)!r}",
                 )
 
     def _check_user_model(self, model):

jupyterhub/apihandlers/users.py

@@ -782,7 +782,7 @@ class SpawnProgressAPIHandler(APIHandler):
                 'progress': 100,
                 'ready': True,
                 'message': f"Server ready at {url}",
-                'html_message': 'Server ready at <a href="{0}">{0}</a>'.format(url),
+                'html_message': f'Server ready at <a href="{url}">{url}</a>',
                 'url': url,
             }
             original_ready_event = ready_event.copy()
@@ -881,9 +881,7 @@ def _parse_timestamp(timestamp):
     if (dt - now) > timedelta(minutes=59):
         raise web.HTTPError(
             400,
-            "Rejecting activity from more than an hour in the future: {}".format(
-                isoformat(dt)
-            ),
+            f"Rejecting activity from more than an hour in the future: {isoformat(dt)}",
         )
     return dt
 

jupyterhub/app.py

@@ -24,8 +24,6 @@ from textwrap import dedent
 from typing import Optional
 from urllib.parse import unquote, urlparse, urlunparse
 
-if sys.version_info[:2] < (3, 3):
-    raise ValueError("Python < 3.3 not supported: %s" % sys.version)
 
 import tornado.httpserver
 import tornado.options
@@ -385,9 +383,7 @@ class JupyterHub(Application):
     def _validate_config_file(self, proposal):
         if not self.generate_config and not os.path.isfile(proposal.value):
             print(
-                "ERROR: Failed to find specified config file: {}".format(
-                    proposal.value
-                ),
+                f"ERROR: Failed to find specified config file: {proposal.value}",
                 file=sys.stderr,
             )
             sys.exit(1)
@@ -1581,7 +1577,7 @@ class JupyterHub(Application):
         if change.new:
             self.log.warning(
                 dedent(
-                    """
+                    f"""
                 extra_log_file is DEPRECATED in jupyterhub-0.8.2.
 
                 extra_log_file only redirects logs of the Hub itself,
@@ -1591,10 +1587,8 @@ class JupyterHub(Application):
                 It is STRONGLY recommended that you redirect process
                 output instead, e.g.
 
-                    jupyterhub &>> '{}'
-            """.format(
-                        change.new
-                    )
+                    jupyterhub &>> '{change.new}'
+            """
                 )
             )
 
@@ -1962,9 +1956,7 @@ class JupyterHub(Application):
         if urlinfo.password:
             # avoid logging the database password
             urlinfo = urlinfo._replace(
-                netloc='{}:[redacted]@{}:{}'.format(
-                    urlinfo.username, urlinfo.hostname, urlinfo.port
-                )
+                netloc=f'{urlinfo.username}:[redacted]@{urlinfo.hostname}:{urlinfo.port}'
             )
             db_log_url = urlinfo.geturl()
         else:
@@ -3496,9 +3488,7 @@ class JupyterHub(Application):
                 self.internal_ssl = True
             self.init_internal_ssl()
             self.log.info(
-                "Certificates written to directory `{}`".format(
-                    self.internal_certs_location
-                )
+                f"Certificates written to directory `{self.internal_certs_location}`"
             )
             loop.stop()
             return

jupyterhub/auth.py

@@ -820,13 +820,8 @@ def _deprecated_method(old_name, new_name, version):
     def deprecated(self, *args, **kwargs):
         warnings.warn(
             (
-                "{cls}.{old_name} is deprecated in JupyterHub {version}."
-                " Please use {cls}.{new_name} instead."
-            ).format(
-                cls=self.__class__.__name__,
-                old_name=old_name,
-                new_name=new_name,
-                version=version,
+                f"{self.__class__.__name__}.{old_name} is deprecated in JupyterHub {version}."
+                f" Please use {self.__class__.__name__}.{new_name} instead."
             ),
             DeprecationWarning,
             stacklevel=2,
@@ -961,11 +956,9 @@ class LocalAuthenticator(Authenticator):
                 await maybe_future(self.add_system_user(user))
             else:
                 raise KeyError(
-                    "User {} does not exist on the system."
+                    f"User {user.name} does not exist on the system."
                     " Set LocalAuthenticator.create_system_users=True"
-                    " to automatically create system users from jupyterhub users.".format(
-                        user.name
-                    )
+                    " to automatically create system users from jupyterhub users."
                 )
 
         await maybe_future(super().add_user(user))

jupyterhub/dbutil.py

@@ -121,9 +121,7 @@ def upgrade_if_needed(db_url, backup=True, log=None):
     if urlinfo.password:
         # avoid logging the database password
         urlinfo = urlinfo._replace(
-            netloc='{}:[redacted]@{}:{}'.format(
-                urlinfo.username, urlinfo.hostname, urlinfo.port
-            )
+            netloc=f'{urlinfo.username}:[redacted]@{urlinfo.hostname}:{urlinfo.port}'
         )
         db_log_url = urlinfo.geturl()
     else:

jupyterhub/handlers/base.py

@@ -372,7 +372,7 @@ class BaseHandler(RequestHandler):
             auth_info['auth_state'] = await user.get_auth_state()
         return await self.auth_to_user(auth_info, user)
 
-    @functools.lru_cache()
+    @functools.lru_cache
     def get_token(self):
         """get token from authorization header"""
         token = self.get_auth_token()
@@ -473,7 +473,7 @@ class BaseHandler(RequestHandler):
                 self.expanded_scopes = scopes.get_scopes_for(self.current_user)
         self.parsed_scopes = scopes.parse_scopes(self.expanded_scopes)
 
-    @functools.lru_cache()
+    @functools.lru_cache
     def get_scope_filter(self, req_scope):
         """Produce a filter function for req_scope on resources
 
@@ -981,9 +981,7 @@ class BaseHandler(RequestHandler):
             )
             err = web.HTTPError(
                 429,
-                "Too many users trying to log in right now. Try again in {}.".format(
-                    human_retry_time
-                ),
+                f"Too many users trying to log in right now. Try again in {human_retry_time}.",
             )
             # can't call set_header directly here because it gets ignored
             # when errors are raised
@@ -1155,8 +1153,7 @@ class BaseHandler(RequestHandler):
 
                 raise web.HTTPError(
                     500,
-                    "Spawner failed to start [status=%s]. The logs for %s may contain details."
-                    % (status, spawner._log_name),
+                    f"Spawner failed to start [status={status}]. The logs for {spawner._log_name} may contain details.",
                 )
 
             if spawner._waiting_for_response:
@@ -1295,7 +1292,7 @@ class BaseHandler(RequestHandler):
         home = url_path_join(self.hub.base_url, 'home')
         return (
             "You can try restarting your server from the "
-            "<a href='{home}'>home page</a>.".format(home=home)
+            f"<a href='{home}'>home page</a>."
         )
 
     def get_template(self, name, sync=False):

jupyterhub/objects.py

@@ -163,9 +163,7 @@ class Server(HasTraits):
         return f"{self.host}{self.base_url}"
 
     def __repr__(self):
-        return "{name}(url={url}, bind_url={bind})".format(
-            name=self.__class__.__name__, url=self.url, bind=self.bind_url
-        )
+        return f"{self.__class__.__name__}(url={self.url}, bind_url={self.bind_url})"
 
     def wait_up(self, timeout=10, http=False, ssl_context=None, extra_path=""):
         """Wait for this server to come up"""

jupyterhub/orm.py

@@ -730,7 +730,7 @@ class _Share:
         return cls._apply_filter(frozenset(scopes), spawner.user.name, spawner.name)
 
     @staticmethod
-    @lru_cache()
+    @lru_cache
     def _apply_filter(scopes, owner_name, server_name):
         """
         implementation of Share.apply_filter
@@ -1518,11 +1518,9 @@ def check_db_revision(engine):
         app_log.debug("database schema version found: %s", alembic_revision)
     else:
         raise DatabaseSchemaMismatch(
-            "Found database schema version {found} != {head}. "
+            f"Found database schema version {alembic_revision} != {head}. "
             "Backup your database and run `jupyterhub upgrade-db`"
-            " to upgrade to the latest schema.".format(
-                found=alembic_revision, head=head
-            )
+            " to upgrade to the latest schema."
         )
 
 

jupyterhub/proxy.py

@@ -337,8 +337,7 @@ class Proxy(LoggingConfigurable):
 
         if spawner.pending and spawner.pending != 'spawn':
             raise RuntimeError(
-                "%s is pending %s, shouldn't be added to the proxy yet!"
-                % (spawner._log_name, spawner.pending)
+                f"{spawner._log_name} is pending {spawner.pending}, shouldn't be added to the proxy yet!"
             )
 
         await self.add_route(
@@ -941,9 +940,7 @@ class ConfigurableHTTPProxy(Proxy):
                 # errors.
                 if e.code >= 500:
                     self.log.warning(
-                        "api_request to the proxy failed with status code {}, retrying...".format(
-                            e.code
-                        )
+                        f"api_request to the proxy failed with status code {e.code}, retrying..."
                     )
                     return False  # a falsy return value make exponential_backoff retry
                 else:

jupyterhub/scopes.py

@@ -212,7 +212,7 @@ def _intersect_expanded_scopes(scopes_a, scopes_b, db=None):
     scopes_b = frozenset(scopes_b)
 
     # cached lookups for group membership of users and servers
-    @lru_cache()
+    @lru_cache
     def groups_for_user(username):
         """Get set of group names for a given username"""
         # if we need a group lookup, the result is not cacheable
@@ -225,7 +225,7 @@ def _intersect_expanded_scopes(scopes_a, scopes_b, db=None):
         )
         return {row[0] for row in group_query}
 
-    @lru_cache()
+    @lru_cache
     def groups_for_server(server):
         """Get set of group names for a given server"""
         username, _, servername = server.partition("/")
@@ -456,7 +456,7 @@ def expand_share_scopes(share):
     )
 
 
-@lru_cache()
+@lru_cache
 def _expand_self_scope(username):
     """
     Users have a metascope 'self' that should be expanded to standard user privileges.

jupyterhub/tests/test_api.py

@@ -1194,7 +1194,7 @@ async def test_progress(request, app, no_patience, slow_spawn):
     assert evt == {
         'progress': 100,
         'message': f'Server ready at {url}',
-        'html_message': 'Server ready at <a href="{0}">{0}</a>'.format(url),
+        'html_message': f'Server ready at <a href="{url}">{url}</a>',
         'url': url,
         'ready': True,
     }
@@ -1307,7 +1307,7 @@ async def test_progress_ready_hook_async_func_exception(request, app):
     db = app.db
     name = 'saga'
     app_user = add_user(db, app=app, name=name)
-    html_message = 'Server ready at <a href="{0}">{0}</a>'.format(app_user.url)
+    html_message = f'Server ready at <a href="{app_user.url}">{app_user.url}</a>'
     spawner = app_user.spawner
 
     async def custom_progress_ready_hook(spawner, ready_event):

jupyterhub/tests/test_named_servers.py

@@ -85,9 +85,7 @@ async def test_default_server(app, named_servers):
                     'pending': None,
                     'ready': True,
                     'stopped': False,
-                    'progress_url': 'PREFIX/hub/api/users/{}/server/progress'.format(
-                        username
-                    ),
+                    'progress_url': f'PREFIX/hub/api/users/{username}/server/progress',
                     'state': {'pid': 0},
                     'user_options': {},
                 }

jupyterhub/traitlets.py

@@ -82,16 +82,12 @@ class ByteSpecification(Integer):
             num = float(value[:-1])
         except ValueError:
             raise TraitError(
-                '{val} is not a valid memory specification. Must be an int or a string with suffix K, M, G, T'.format(
-                    val=value
-                )
+                f'{value} is not a valid memory specification. Must be an int or a string with suffix K, M, G, T'
             )
         suffix = value[-1]
         if suffix not in self.UNIT_SUFFIXES:
             raise TraitError(
-                '{val} is not a valid memory specification. Must be an int or a string with suffix K, M, G, T'.format(
-                    val=value
-                )
+                f'{value} is not a valid memory specification. Must be an int or a string with suffix K, M, G, T'
             )
         else:
             return int(float(num) * self.UNIT_SUFFIXES[suffix])

jupyterhub/user.py

@@ -897,9 +897,7 @@ class User:
                 self.settings['statsd'].incr('spawner.failure.timeout')
             else:
                 self.log.exception(
-                    "Unhandled error starting {user}'s server: {error}".format(
-                        user=self.name, error=e
-                    )
+                    f"Unhandled error starting {self.name}'s server: {e}"
                 )
                 self.settings['statsd'].incr('spawner.failure.error')
                 e.reason = 'error'
@@ -907,9 +905,7 @@ class User:
                 await self.stop(spawner.name)
             except Exception:
                 self.log.exception(
-                    "Failed to cleanup {user}'s server that failed to start".format(
-                        user=self.name
-                    ),
+                    f"Failed to cleanup {self.name}'s server that failed to start",
                     exc_info=True,
                 )
             # raise original exception
@@ -967,9 +963,7 @@ class User:
                 await self.stop(spawner.name)
             except Exception:
                 self.log.exception(
-                    "Failed to cleanup {user}'s server that failed to start".format(
-                        user=self.name
-                    ),
+                    f"Failed to cleanup {self.name}'s server that failed to start",
                     exc_info=True,
                 )
             # raise original TimeoutError

jupyterhub/utils.py

@@ -253,9 +253,7 @@ async def wait_for_server(ip, port, timeout=10):
     tic = time.perf_counter()
     await exponential_backoff(
         lambda: can_connect(ip, port),
-        "Server at {ip}:{port} didn't respond in {timeout} seconds".format(
-            ip=ip, port=port, timeout=timeout
-        ),
+        f"Server at {ip}:{port} didn't respond in {timeout} seconds",
         timeout=timeout,
     )
     toc = time.perf_counter()
@@ -301,9 +299,7 @@ async def wait_for_http_server(url, timeout=10, ssl_context=None):
 
     re = await exponential_backoff(
         is_reachable,
-        "Server at {url} didn't respond in {timeout} seconds".format(
-            url=url, timeout=timeout
-        ),
+        f"Server at {url} didn't respond in {timeout} seconds",
         timeout=timeout,
     )
     toc = time.perf_counter()
@@ -507,14 +503,12 @@ def print_ps_info(file=sys.stderr):
     threadlen = len('threads')
 
     print(
-        "%s %s %s %s"
-        % ('%CPU'.ljust(cpulen), 'MEM'.ljust(memlen), 'FDs'.ljust(fdlen), 'threads'),
+        "{} {} {} {}".format('%CPU'.ljust(cpulen), 'MEM'.ljust(memlen), 'FDs'.ljust(fdlen), 'threads'),
         file=file,
     )
 
     print(
-        "%s %s %s %s"
-        % (
+        "{} {} {} {}".format(
             cpu_s.ljust(cpulen),
             mem_s.ljust(memlen),
             fd_s.ljust(fdlen),
@@ -788,7 +782,7 @@ _dns_safe = set(string.ascii_letters + string.digits + '-.')
 _dns_needs_replace = _dns_safe | {"%"}
 
 
-@lru_cache()
+@lru_cache
 def _dns_quote(name):
     """Escape a name for use in a dns label