fix: missing method implementation and potential bug in the DatabaseWrapper class

django_spanner/base.py

@@ -5,7 +5,9 @@
 # https://developers.google.com/open-source/licenses/bsd
 
 from django.db.backends.base.base import BaseDatabaseWrapper
-from google.cloud import spanner_dbapi as Database, spanner_v1 as spanner
+
+import google.cloud.spanner_dbapi as Database
+import google.cloud.spanner_v1 as spanner
 
 from .client import DatabaseClient
 from .creation import DatabaseCreation
@@ -81,8 +83,9 @@ class DatabaseWrapper(BaseDatabaseWrapper):
  # special characters for REGEXP_CONTAINS operators (e.g. \, *, _) must be
  # escaped on database side.
  pattern_esc = r'REPLACE(REPLACE(REPLACE({}, "\\", "\\\\"), "%%", r"\%%"), "_", r"\_")'
- # These are all no-ops in favor of using REGEXP_CONTAINS in the customized
- # lookups.
+
+ # These are all no-ops in favor of using REGEXP_CONTAINS
+ # in the customized lookups.
  pattern_ops = {
  "contains": "",
  "icontains": "",
@@ -124,7 +127,9 @@ def get_new_connection(self, conn_params):
  return Database.connect(**conn_params)
 
  def init_connection_state(self):
- pass
+ self.connection.close()
+ database = self.connection.database
+ self.connection.__init__(self.instance, database)
 
  def create_cursor(self, name=None):
  return self.connection.cursor()
@@ -134,12 +139,13 @@ def _set_autocommit(self, autocommit):
  self.connection.autocommit = autocommit
 
  def is_usable(self):
- if self.connection is None:
+ if self.connection is None or self.connection.is_closed:
  return False
+
  try:
  # Use a cursor directly, bypassing Django's utilities.
  self.connection.cursor().execute("SELECT 1")
  except Database.Error:
  return False
- else:
-  return True
+
+ return True