feat: enable instance-level connection (#316)

* chore: auto-release

* feat:enable instance-level connection

* lint

Author: asthamohta

google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py

@@ -645,11 +645,14 @@ def create_connect_args(self, url):
 
         The given URL follows the style:
         `spanner:///projects/{project-id}/instances/{instance-id}/databases/{database-id}`
+        or `spanner:///projects/{project-id}/instances/{instance-id}`. For the latter,
+        database operations will be not be possible and if required a new engine with
+        database-id set will need to be created.
         """
         match = re.match(
             (
                 r"^projects/(?P<project>.+?)/instances/"
-                "(?P<instance>.+?)/databases/(?P<database>.+?)$"
+                "(?P<instance>.+?)(/databases/(?P<database>.+)|$)"
             ),
             url.database,
         )
@@ -1346,17 +1349,29 @@ def do_rollback(self, dbapi_connection):
         ):
             pass
         else:
-            trace_attributes = {"db.instance": dbapi_connection.database.name}
+            trace_attributes = {
+                "db.instance": dbapi_connection.database.name
+                if dbapi_connection.database
+                else ""
+            }
             with trace_call("SpannerSqlAlchemy.Rollback", trace_attributes):
                 dbapi_connection.rollback()
 
     def do_commit(self, dbapi_connection):
-        trace_attributes = {"db.instance": dbapi_connection.database.name}
+        trace_attributes = {
+            "db.instance": dbapi_connection.database.name
+            if dbapi_connection.database
+            else ""
+        }
         with trace_call("SpannerSqlAlchemy.Commit", trace_attributes):
             dbapi_connection.commit()
 
     def do_close(self, dbapi_connection):
-        trace_attributes = {"db.instance": dbapi_connection.database.name}
+        trace_attributes = {
+            "db.instance": dbapi_connection.database.name
+            if dbapi_connection.database
+            else ""
+        }
         with trace_call("SpannerSqlAlchemy.Close", trace_attributes):
             dbapi_connection.close()
 

test/test_suite_13.py

@@ -2045,3 +2045,17 @@ def test_create_engine_w_invalid_client_object(self):
 
         with pytest.raises(ValueError):
             engine.connect()
+
+
+class CreateEngineWithoutDatabaseTest(fixtures.TestBase):
+    def test_create_engine_wo_database(self):
+        """
+        SPANNER TEST:
+
+        Check that we can connect to SqlAlchemy
+        without passing database id in the
+        connection URL.
+        """
+        engine = create_engine(get_db_url().split("/database")[0])
+        with engine.connect() as connection:
+            assert connection.connection.database is None

test/test_suite_14.py

@@ -2378,3 +2378,17 @@ def test_create_engine_w_invalid_client_object(self):
 
         with pytest.raises(ValueError):
             engine.connect()
+
+
+class CreateEngineWithoutDatabaseTest(fixtures.TestBase):
+    def test_create_engine_wo_database(self):
+        """
+        SPANNER TEST:
+
+        Check that we can connect to SqlAlchemy
+        without passing database id in the
+        connection URL.
+        """
+        engine = create_engine(get_db_url().split("/database")[0])
+        with engine.connect() as connection:
+            assert connection.connection.database is None

test/test_suite_20.py

@@ -24,7 +24,7 @@
 import time
 from unittest import mock
 
-from google.cloud.spanner_v1 import RequestOptions
+from google.cloud.spanner_v1 import RequestOptions, Client
 import sqlalchemy
 from sqlalchemy import create_engine
 from sqlalchemy.engine import Inspector
@@ -144,7 +144,7 @@
     UnicodeTextTest as _UnicodeTextTest,
     _UnicodeFixture as __UnicodeFixture,
 )  # noqa: F401, F403
-from test._helpers import get_db_url
+from test._helpers import get_db_url, get_project
 
 config.test_schema = ""
 
@@ -3000,3 +3000,44 @@ def test_request_priority(self):
         engine = create_engine("sqlite:///database")
         with engine.connect() as connection:
             pass
+
+
+class CreateEngineWithClientObjectTest(fixtures.TestBase):
+    def test_create_engine_w_valid_client_object(self):
+        """
+        SPANNER TEST:
+
+        Check that we can connect to SqlAlchemy
+        by passing custom Client object.
+        """
+        client = Client(project=get_project())
+        engine = create_engine(get_db_url(), connect_args={"client": client})
+        with engine.connect() as connection:
+            assert connection.connection.instance._client == client
+
+    def test_create_engine_w_invalid_client_object(self):
+        """
+        SPANNER TEST:
+
+        Check that if project id in url and custom Client
+        Object passed to enginer mismatch, error is thrown.
+        """
+        client = Client(project="project_id")
+        engine = create_engine(get_db_url(), connect_args={"client": client})
+
+        with pytest.raises(ValueError):
+            engine.connect()
+
+
+class CreateEngineWithoutDatabaseTest(fixtures.TestBase):
+    def test_create_engine_wo_database(self):
+        """
+        SPANNER TEST:
+
+        Check that we can connect to SqlAlchemy
+        without passing database id in the
+        connection URL.
+        """
+        engine = create_engine(get_db_url().split("/database")[0])
+        with engine.connect() as connection:
+            assert connection.connection.database is None