feat: durable runtime support

src/google/adk/agents/invocation_context.py

@@ -16,7 +16,8 @@
 
 from typing import Any
 from typing import Optional
-import uuid
+
+from google.adk.platform import uuid as platform_uuid
 
 from google.genai import types
 from pydantic import BaseModel
@@ -409,4 +410,4 @@ def _find_matching_function_call(
 
 
 def new_invocation_context_id() -> str:
-  return "e-" + str(uuid.uuid4())
+  return "e-" + platform_uuid.new_uuid()

src/google/adk/artifacts/base_artifact_service.py

@@ -19,6 +19,8 @@
 from typing import Any
 from typing import Optional
 
+from google.adk.platform import time as platform_time
+
 from google.genai import types
 from pydantic import alias_generators
 from pydantic import BaseModel
@@ -47,7 +49,7 @@ class ArtifactVersion(BaseModel):
       description="Optional user-supplied metadata stored with the artifact.",
   )
   create_time: float = Field(
-      default_factory=lambda: datetime.now().timestamp(),
+      default_factory=lambda: platform_time.get_time(),
       description=(
           "Unix timestamp (seconds) when the version record was created."
       ),

src/google/adk/events/event.py

@@ -18,6 +18,8 @@
 from typing import Optional
 import uuid
 
+from google.adk.platform import time as platform_time
+from google.adk.platform import uuid as platform_uuid
 from google.genai import types
 from pydantic import alias_generators
 from pydantic import ConfigDict
@@ -70,7 +72,7 @@ class Event(LlmResponse):
   # Do not assign the ID. It will be assigned by the session.
   id: str = ''
   """The unique identifier of the event."""
-  timestamp: float = Field(default_factory=lambda: datetime.now().timestamp())
+  timestamp: float = Field(default_factory=lambda: platform_time.get_time())
   """The timestamp of the event."""
 
   def model_post_init(self, __context):
@@ -125,4 +127,4 @@ def has_trailing_code_execution_result(
 
   @staticmethod
   def new_id():
-    return str(uuid.uuid4())
+    return platform_uuid.new_uuid()

src/google/adk/flows/llm_flows/functions.py

@@ -29,8 +29,8 @@
 from typing import Dict
 from typing import Optional
 from typing import TYPE_CHECKING
-import uuid
 
+from google.adk.platform import uuid as platform_uuid
 from google.genai import types
 
 from ...agents.active_streaming_tool import ActiveStreamingTool
@@ -175,7 +175,7 @@ def run_async_tool_in_new_loop():
 
 
 def generate_client_function_call_id() -> str:
-  return f'{AF_FUNCTION_CALL_ID_PREFIX}{uuid.uuid4()}'
+  return f'{AF_FUNCTION_CALL_ID_PREFIX}{platform_uuid.new_uuid()}'
 
 
 def populate_client_function_call_id(model_response_event: Event) -> None:

src/google/adk/platform/time.py

@@ -0,0 +1,43 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Platform module for abstracting system time generation."""
+
+import time
+from typing import Callable
+
+_default_time_provider: Callable[[], float] = time.time
+_time_provider: Callable[[], float] = _default_time_provider
+
+
+def set_time_provider(provider: Callable[[], float]) -> None:
+  """Sets the provider for the current time.
+
+  Args:
+    provider: A callable that returns the current time in seconds since the
+      epoch.
+  """
+  global _time_provider
+  _time_provider = provider
+
+
+def reset_time_provider() -> None:
+  """Resets the time provider to its default implementation."""
+  global _time_provider
+  _time_provider = _default_time_provider
+
+
+def get_time() -> float:
+  """Returns the current time in seconds since the epoch."""
+  return _time_provider()

src/google/adk/platform/uuid.py

@@ -0,0 +1,42 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Platform module for abstracting unique ID generation."""
+
+import uuid
+from typing import Callable
+
+_default_id_provider: Callable[[], str] = lambda: str(uuid.uuid4())
+_id_provider: Callable[[], str] = _default_id_provider
+
+
+def set_id_provider(provider: Callable[[], str]) -> None:
+  """Sets the provider for generating unique IDs.
+
+  Args:
+    provider: A callable that returns a unique ID string.
+  """
+  global _id_provider
+  _id_provider = provider
+
+
+def reset_id_provider() -> None:
+  """Resets the ID provider to its default implementation."""
+  global _id_provider
+  _id_provider = _default_id_provider
+
+
+def new_uuid() -> str:
+  """Returns a new unique ID."""
+  return _id_provider()

src/google/adk/sessions/in_memory_session_service.py

@@ -22,6 +22,8 @@
 
 from typing_extensions import override
 
+from google.adk.platform import time as platform_time
+from google.adk.platform import uuid as platform_uuid
 from . import _session_util
 from ..errors.already_exists_error import AlreadyExistsError
 from ..events.event import Event
@@ -108,14 +110,14 @@ def _create_session_impl(
     session_id = (
         session_id.strip()
         if session_id and session_id.strip()
-        else str(uuid.uuid4())
+        else platform_uuid.new_uuid()
     )
     session = Session(
         app_name=app_name,
         user_id=user_id,
         id=session_id,
         state=session_state or {},
-        last_update_time=time.time(),
+        last_update_time=platform_time.get_time(),
     )
 
     if app_name not in self.sessions:

src/google/adk/sessions/sqlite_session_service.py

@@ -29,6 +29,9 @@
 import aiosqlite
 from typing_extensions import override
 
+from google.adk.platform import time as platform_time
+from google.adk.platform import uuid as platform_uuid
+
 from . import _session_util
 from ..errors.already_exists_error import AlreadyExistsError
 from ..events.event import Event
@@ -165,8 +168,8 @@ async def create_session(
     if session_id:
       session_id = session_id.strip()
     if not session_id:
-      session_id = str(uuid.uuid4())
-    now = time.time()
+      session_id = platform_uuid.new_uuid()
+    now = platform_time.get_time()
 
     async with self._get_db_connection() as db:
       # Check if session_id already exists

tests/unittests/artifacts/test_artifact_service.py

@@ -418,9 +418,9 @@ async def test_list_artifact_versions_and_get_artifact_version(
   ]
 
   with patch(
-      "google.adk.artifacts.base_artifact_service.datetime"
-  ) as mock_datetime:
-    mock_datetime.now.return_value = FIXED_DATETIME
+      "google.adk.artifacts.base_artifact_service.platform_time"
+  ) as mock_platform_time:
+    mock_platform_time.get_time.return_value = FIXED_DATETIME.timestamp()
 
     for i in range(4):
       custom_metadata = {"key": "value" + str(i)}
@@ -505,9 +505,9 @@ async def test_list_artifact_versions_with_user_prefix(
   ]
 
   with patch(
-      "google.adk.artifacts.base_artifact_service.datetime"
-  ) as mock_datetime:
-    mock_datetime.now.return_value = FIXED_DATETIME
+      "google.adk.artifacts.base_artifact_service.platform_time"
+  ) as mock_platform_time:
+    mock_platform_time.get_time.return_value = FIXED_DATETIME.timestamp()
 
     for i in range(4):
       custom_metadata = {"key": "value" + str(i)}

tests/unittests/platform/test_time.py

@@ -0,0 +1,40 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for the platform time module."""
+
+import time
+import unittest
+
+from google.adk.platform import time as platform_time
+
+
+class TestTime(unittest.TestCase):
+
+    def tearDown(self):
+        # Reset provider to default after each test
+        platform_time.reset_time_provider()
+
+    def test_default_time_provider(self):
+        # Verify it returns a float that is close to now
+        now = time.time()
+        rt_time = platform_time.get_time()
+        self.assertIsInstance(rt_time, float)
+        self.assertAlmostEqual(rt_time, now, delta=1.0)
+
+    def test_custom_time_provider(self):
+        # Test override
+        mock_time = 123456789.0
+        platform_time.set_time_provider(lambda: mock_time)
+        self.assertEqual(platform_time.get_time(), mock_time)

tests/unittests/platform/test_uuid.py

@@ -0,0 +1,40 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for the platform uuid module."""
+
+import uuid
+import unittest
+
+from google.adk.platform import uuid as platform_uuid
+
+
+class TestUUID(unittest.TestCase):
+
+    def tearDown(self):
+        # Reset provider to default after each test
+        platform_uuid.reset_id_provider()
+
+    def test_default_id_provider(self):
+        # Verify it returns a string uuid
+        uid = platform_uuid.new_uuid()
+        self.assertIsInstance(uid, str)
+        # Should be parseable as uuid
+        uuid.UUID(uid)
+
+    def test_custom_id_provider(self):
+        # Test override
+        mock_id = "test-id-123"
+        platform_uuid.set_id_provider(lambda: mock_id)
+        self.assertEqual(platform_uuid.new_uuid(), mock_id)