feat!: Introduction of ADK folder for local session and artifact storage

Default CLI session storage to SQLite instead of in-memory

Previously, adk run and adk web used in-memory session storage by default, causing sessions to be lost on restart. Now sessions persist to .adk/session.db automatically. To use in-memory storage, pass --session-service-uri memory://

Co-authored-by: George Weale <gweale@google.com>
PiperOrigin-RevId: 838975328

tests/unittests/cli/utils/test_service_factory.py

@@ -19,10 +19,10 @@ from __future__ import annotations
 from pathlib import Path
 from unittest.mock import Mock
 
+from google.adk.cli.utils.local_storage import PerAgentDatabaseSessionService
 import google.adk.cli.utils.service_factory as service_factory
 from google.adk.memory.in_memory_memory_service import InMemoryMemoryService
 from google.adk.sessions.database_session_service import DatabaseSessionService
-from google.adk.sessions.in_memory_session_service import InMemorySessionService
 import pytest
 
 
@@ -44,12 +44,20 @@ def test_create_session_service_uses_registry(tmp_path: Path, monkeypatch):
   )
 
 
-def test_create_session_service_defaults_to_memory(tmp_path: Path):
+@pytest.mark.asyncio
+async def test_create_session_service_defaults_to_per_agent_sqlite(
+    tmp_path: Path,
+) -> None:
+  agent_dir = tmp_path / "agent_a"
+  agent_dir.mkdir()
   service = service_factory.create_session_service_from_options(
       base_dir=tmp_path,
   )
 
-  assert isinstance(service, InMemorySessionService)
+  assert isinstance(service, PerAgentDatabaseSessionService)
+  session = await service.create_session(app_name="agent_a", user_id="user")
+  assert session.app_name == "agent_a"
+  assert (agent_dir / ".adk" / "session.db").exists()
 
 
 def test_create_session_service_fallbacks_to_database(