refactor: refactor cli to use agent loader

PiperOrigin-RevId: 764546019

src/google/adk/cli/cli.py

@@ -12,10 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 from datetime import datetime
-import importlib
-import os
-import sys
 from typing import Optional
 
 import click
@@ -30,6 +29,7 @@ from ..sessions.base_session_service import BaseSessionService
 from ..sessions.in_memory_session_service import InMemorySessionService
 from ..sessions.session import Session
 from .utils import envs
+from .utils.agent_loader import AgentLoader
 
 
 class InputFile(BaseModel):
@@ -122,19 +122,17 @@ async def run_cli(
     save_session: bool, whether to save the session on exit.
     session_id: Optional[str], the session ID to save the session to on exit.
   """
-  if agent_parent_dir not in sys.path:
-    sys.path.append(agent_parent_dir)
 
   artifact_service = InMemoryArtifactService()
   session_service = InMemorySessionService()
 
-  agent_module_path = os.path.join(agent_parent_dir, agent_folder_name)
-  agent_module = importlib.import_module(agent_folder_name)
   user_id = 'test_user'
   session = await session_service.create_session(
       app_name=agent_folder_name, user_id=user_id
   )
-  root_agent = agent_module.agent.root_agent
+  root_agent = AgentLoader(agents_dir=agent_parent_dir).load_agent(
+      agent_folder_name
+  )
   envs.load_dotenv_for_agent(agent_folder_name, agent_parent_dir)
   if input_file:
     session = await run_input_file(
@@ -177,7 +175,9 @@ async def run_cli(
 
   if save_session:
     session_id = session_id or input('Session ID to save: ')
-    session_path = f'{agent_module_path}/{session_id}.session.json'
+    session_path = (
+        f'{agent_parent_dir}/{agent_folder_name}/{session_id}.session.json'
+    )
 
     # Fetch the session again to get all the details.
     session = await session_service.get_session(

tests/unittests/cli/utils/test_cli.py

@@ -18,7 +18,7 @@ from __future__ import annotations
 
 import json
 from pathlib import Path
-import sys
+from textwrap import dedent
 import types
 from typing import Any
 from typing import Dict
@@ -87,7 +87,7 @@ def _patch_types_and_runner(monkeypatch: pytest.MonkeyPatch) -> None:
 
 
 @pytest.fixture()
-def fake_agent(tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
+def fake_agent(tmp_path: Path):
   """Create a minimal importable agent package and patch importlib."""
 
   parent_dir = tmp_path / "agents"
@@ -95,27 +95,16 @@ def fake_agent(tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
   agent_dir = parent_dir / "fake_agent"
   agent_dir.mkdir()
   # __init__.py exposes root_agent with .name
-  (agent_dir / "__init__.py").write_text(
-      "from types import SimpleNamespace\n"
-      "root_agent = SimpleNamespace(name='fake_root')\n"
-  )
+  (agent_dir / "__init__.py").write_text(dedent("""
+    from google.adk.agents.base_agent import BaseAgent
+    class FakeAgent(BaseAgent):
+      def __init__(self, name):
+        super().__init__(name=name)
 
-  # Ensure importable via sys.path
-  sys.path.insert(0, str(parent_dir))
+    root_agent = FakeAgent(name="fake_root")
+    """))
 
-  import importlib
-
-  module = importlib.import_module("fake_agent")
-  fake_module = types.SimpleNamespace(agent=module)
-
-  monkeypatch.setattr(importlib, "import_module", lambda n: fake_module)
-  monkeypatch.setattr(cli.envs, "load_dotenv_for_agent", lambda *a, **k: None)
-
-  yield parent_dir, "fake_agent"
-
-  # Cleanup
-  sys.path.remove(str(parent_dir))
-  del sys.modules["fake_agent"]
+  return parent_dir, "fake_agent"
 
 
 # _run_input_file