Deprecation imports google.appengine.api.rdbms in _gae and google adapter

[jparga]

This warning appears when running in google app engine:

Please remove any imports of google.appengine.api.rdbms. First Generation Cloud SQL instances have been shut down, and rdbms.py will be removed in a future release. See: https://cloud.google.com/sql/docs/mysql/deprecation-notice

The rdbms library is imported in _gae.py:
`# -- coding: utf-8 --

try:
from new import classobj
except ImportError:
classobj = type

try:
from google.appengine.ext import db as gae
except ImportError:
gae = None
Key = None
else:
from google.appengine.ext import ndb
from google.appengine.api import namespace_manager, rdbms
from google.appengine.api.datastore_types import Key # for belongs on ID
from google.appengine.ext.ndb.polymodel import PolyModel as NDBPolyModel`

And it is used for the google:sql connection in google.py adpater:

`if gae:
from .._gae import ndb, rdbms, namespace_manager, classobj, NDBPolyModel
from ..helpers.gae import NDBDecimalProperty

class GoogleMigratorMixin(object):
migrator_cls = InDBMigrator

@adapters.register_for("google:sql")
class GoogleSQL(GoogleMigratorMixin, MySQL):
uploads_in_blob = True
REGEX_URI = "^(?P.*)/(?P.+)$"

def _find_work_folder(self):
    super(GoogleSQL, self)._find_work_folder()
    if os.path.isabs(self.folder) and self.folder.startswith(os.getcwd()):
        self.folder = os.path.relpath(self.folder, os.getcwd())

def _initialize_(self):
    super(GoogleSQL, self)._initialize_()
    self.folder = self.folder or pjoin(
        "$HOME",
        THREAD_LOCAL._pydal_folder_.split(os.sep + "applications" + os.sep, 1)[1],
    )
    ruri = self.uri.split("://", 1)[1]
    m = re.match(self.REGEX_URI, ruri)
    if not m:
        raise SyntaxError("Invalid URI string in DAL")
    self.driver_args["instance"] = self.credential_decoder(m.group("instance"))
    self.dbstring = self.credential_decoder(m.group("db"))
    self.createdb = self.adapter_args.get("createdb", True)
    if not self.createdb:
        self.driver_args["database"] = self.dbstring

def find_driver(self):
    self.driver = "google"

def connector(self):
    return rdbms.connect(**self.driver_args)

`

https://cloud.google.com/appengine/docs/standard/python/refdocs/modules/google/appengine/api/rdbms#connect

[thedeltaflyer]

google.appengine.api.rdbms has now been removed from the Python 3 appengine-python-standard library

Simply having the library installed will cause an import error:

...[truncated for clarity]...
    from pydal import Field
  File "/path/to/venv/lib/python3.11/site-packages/pydal/__init__.py", line 3, in <module>
    from .base import DAL
  File "/path/to/venv/lib/python3.11/site-packages/pydal/base.py", line 168, in <module>
    from .objects import Table, Field, Rows, Row, Set
  File "/path/to/venv/lib/python3.11/site-packages/pydal/objects.py", line 38, in <module>
    from ._gae import Key
  File "/path/to/venv/lib/python3.11/site-packages/pydal/_gae.py", line 15, in <module>
    from google.appengine.api import namespace_manager, rdbms
ImportError: cannot import name 'rdbms' from 'google.appengine.api' (/path/to/venv/lib/python3.11/site-packages/google/appengine/api/__init__.py)

This happens even when not using a "gae" connection string since _gae.py always executes.

For those encountering the issue I have this (inelegant) workaround (place before importing pydal):

try:
    from google.appengine.api import rdbms
except ImportError:
    # Define a "mock" `rdbms` class to serve as a placeholder
    class mock_rdbms():
        pass
    # Set the module
    from sys import modules
    modules['google.appengine.api.rdbms'] = mock_rdbms
    # Set _gae.gae to None to ensure that the mock class is never called
    from pydal import _gae
    _gae.gae = None

I have to assume that the intersection of people needing the appengine api installed and using pydal is small, but hopefully this can get some eyes on it for a permanent fix.