fix: install greenlet with the db extra and name it when missing

Merge #7327

DatabaseSessionService.__init__ now raises ImportError naming 'sqlalchemy[asyncio]' (instead of 'sqlalchemy') when SQLAlchemy or its asyncio extra fails to import.

PiperOrigin-RevId: 991319378

Author: donggyun112

pyproject.toml

@@ -131,7 +131,7 @@ optional-dependencies.all = [
   "redis>=4.2",
   "rouge-score>=0.1.2",
   "slack-bolt>=1.22",
-  "sqlalchemy>=2,<3",
+  "sqlalchemy[asyncio]>=2,<3",
   "sqlalchemy-spanner>=1.14",
   "tabulate>=0.9",
   "toolbox-adk>=1,<2",
@@ -159,7 +159,7 @@ optional-dependencies.daytona = [
   "daytona>=0.191", # For DaytonaEnvironment remote sandbox.
 ]
 optional-dependencies.db = [
-  "sqlalchemy>=2,<3",
+  "sqlalchemy[asyncio]>=2,<3",
   "sqlalchemy-spanner>=1.14",
 ]
 optional-dependencies.dev = [
@@ -349,7 +349,7 @@ optional-dependencies.test = [
   "python-multipart>=0.0.9",
   "rouge-score>=0.1.2",
   "slack-bolt>=1.22",
-  "sqlalchemy>=2,<3",
+  "sqlalchemy[asyncio]>=2,<3",
   "sqlalchemy-spanner>=1.14",
   "tabulate>=0.9",
   "tomli>=2,<3; python_version<'3.11'",

src/google/adk/sessions/database_session_service.py

@@ -31,6 +31,7 @@
 from google.adk.platform import time as platform_time
 from google.adk.platform import uuid as platform_uuid
 
+_sqlalchemy_import_error: ImportError | None = None
 try:
   from sqlalchemy import delete
   from sqlalchemy import event
@@ -49,8 +50,9 @@
   from sqlalchemy.ext.asyncio import AsyncSession as DatabaseSessionFactory
   from sqlalchemy.ext.asyncio import create_async_engine
   from sqlalchemy.pool import StaticPool
-except ImportError:
-  pass
+except ImportError as e:
+  # Re-raised by __init__, so the module still imports without the db extra.
+  _sqlalchemy_import_error = e
 from typing_extensions import override
 
 from . import _session_util
@@ -352,12 +354,15 @@ def __init__(
       ValueError: If neither or both db_url and db_engine are provided, or if
         engine creation fails.
     """
-    try:
-      import sqlalchemy  # noqa: F401
-    except ImportError as e:
+    # Re-importing cannot tell whether the imports above failed: without
+    # greenlet, SQLAlchemy 2.1 raises on the first import of its asyncio
+    # extension and lets later ones succeed.
+    if _sqlalchemy_import_error is not None:
       from ..utils._dependency import missing_extra
 
-      raise missing_extra("sqlalchemy", "db") from e
+      raise missing_extra(
+          "sqlalchemy[asyncio]", "db"
+      ) from _sqlalchemy_import_error
 
     if (db_url is None) == (db_engine is None):
       raise ValueError(

tests/unittests/test_optional_dependencies.py

@@ -146,6 +146,28 @@ def test_database_session_service_fails_on_creation():
     assert "sqlalchemy" in str(exc_info.value)
 
 
+def test_database_session_service_names_its_extra_when_asyncio_failed_to_load():
+  """Without greenlet, SQLAlchemy 2.1 fails only the first asyncio import.
+
+  The module is loaded while that import fails, and the service is created
+  after it would succeed again, as happens in a real environment.
+  """
+  module_name = "google.adk.sessions.database_session_service"
+  original = sys.modules.pop(module_name, None)
+  try:
+    with mock.patch.dict("sys.modules", {"sqlalchemy.ext.asyncio": None}):
+      from google.adk.sessions import DatabaseSessionService
+
+    with pytest.raises(
+        ImportError, match=r"sqlalchemy\[asyncio\].*google-adk\[db\]"
+    ):
+      DatabaseSessionService(db_url="sqlite+aiosqlite:///:memory:")
+  finally:
+    sys.modules.pop(module_name, None)
+    if original is not None:
+      sys.modules[module_name] = original
+
+
 def test_vertex_ai_session_service_fails_on_creation():
   """Verify that creating VertexAiSessionService without extra fails using mocks."""
   try:

tests/unittests/test_release_dependencies.py

@@ -306,6 +306,29 @@ def test_extras_that_reach_aiohttp_indirectly_declare_it(
   assert 'aiohttp' in names, f'The {extra!r} extra needs aiohttp: {reason}.'
 
 
+@pytest.mark.parametrize('extra', ['db', 'all', 'test'])
+def test_sqlalchemy_extras_request_the_asyncio_extra(
+    pyproject: dict, extra: str
+) -> None:
+  """DatabaseSessionService needs greenlet, which SQLAlchemy 2.1 made optional.
+
+  SQLAlchemy 2.0 installed greenlet on common platforms by default. From 2.1 it
+  comes only with ``sqlalchemy[asyncio]``, and without it
+  ``sqlalchemy.ext.asyncio`` fails to import.
+  """
+  wanted = canonicalize_name('sqlalchemy')
+  requirements = [
+      Requirement(entry)
+      for entry in pyproject['project']['optional-dependencies'][extra]
+  ]
+  sqlalchemy = [r for r in requirements if canonicalize_name(r.name) == wanted]
+  assert sqlalchemy, f'The {extra!r} extra must declare sqlalchemy.'
+  assert all('asyncio' in r.extras for r in sqlalchemy), (
+      f'The {extra!r} extra must require sqlalchemy[asyncio]; plain sqlalchemy'
+      ' 2.1+ installs without greenlet, so DatabaseSessionService cannot start.'
+  )
+
+
 def test_main_deps_require_lazy_mcp_google_genai_release(
     pyproject: dict,
 ) -> None: