Merge branch 'main' into fix/handle-circular-refs

Author: foivos-all

contributing/samples/litellm_streaming/__init__.py

@@ -0,0 +1,15 @@
+# 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.
+
+from . import agent

contributing/samples/litellm_streaming/agent.py

@@ -0,0 +1,27 @@
+# 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.
+
+"""LiteLLM sample agent for SSE text streaming."""
+
+from __future__ import annotations
+
+from google.adk import Agent
+from google.adk.models.lite_llm import LiteLlm
+
+root_agent = Agent(
+    name='litellm_streaming_agent',
+    model=LiteLlm(model='gemini/gemini-2.5-flash'),
+    description='A LiteLLM agent used for streaming text responses.',
+    instruction='You are a verbose assistant',
+)

contributing/samples/litellm_streaming/main.py

@@ -0,0 +1,107 @@
+# 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.
+
+"""Runs the LiteLLM streaming sample with SSE enabled."""
+
+from __future__ import annotations
+
+import asyncio
+
+from dotenv import load_dotenv
+from google.adk.agents.run_config import RunConfig
+from google.adk.agents.run_config import StreamingMode
+from google.adk.cli.utils import logs
+from google.adk.runners import InMemoryRunner
+from google.genai import types
+
+from . import agent
+
+load_dotenv(override=True)
+logs.log_to_tmp_folder()
+
+
+async def _run_prompt(
+    *,
+    runner: InMemoryRunner,
+    user_id: str,
+    session_id: str,
+    prompt: str,
+) -> None:
+  """Runs one prompt and prints partial chunks in real time."""
+  content = types.Content(
+      role='user',
+      parts=[types.Part.from_text(text=prompt)],
+  )
+
+  print(f'User: {prompt}')
+  print('Agent: ', end='', flush=True)
+  saw_text = False
+  saw_partial_text = False
+
+  # For `adk web`, enable the `Streaming` toggle in the UI to get
+  # partial SSE responses similar to this script.
+  async for event in runner.run_async(
+      user_id=user_id,
+      session_id=session_id,
+      new_message=content,
+      run_config=RunConfig(streaming_mode=StreamingMode.SSE),
+  ):
+    if not event.content:
+      continue
+    text = ''.join(part.text for part in event.content.parts if part.text)
+    if not text:
+      continue
+
+    if event.partial:
+      print(text, end='', flush=True)
+      saw_text = True
+      saw_partial_text = True
+      continue
+
+    # With SSE mode, ADK emits a final aggregated event after partial chunks.
+    if not saw_partial_text:
+      print(text, end='', flush=True)
+      saw_text = True
+
+  if saw_text:
+    print()
+  else:
+    print('(no text response)')
+  print('------------------------------------')
+
+
+async def main() -> None:
+  app_name = 'litellm_streaming_demo'
+  user_id = 'user_1'
+  runner = InMemoryRunner(agent=agent.root_agent, app_name=app_name)
+  session = await runner.session_service.create_session(
+      app_name=app_name,
+      user_id=user_id,
+  )
+  prompts = [
+      'Write an essay about the roman empire',
+      'Now summarize the essay into one sentence.',
+  ]
+
+  for prompt in prompts:
+    await _run_prompt(
+        runner=runner,
+        user_id=user_id,
+        session_id=session.id,
+        prompt=prompt,
+    )
+
+
+if __name__ == '__main__':
+  asyncio.run(main())

src/google/adk/agents/callback_context.py

@@ -14,240 +14,9 @@
 
 from __future__ import annotations
 
-from collections.abc import Mapping
-from collections.abc import Sequence
-from typing import Any
-from typing import Optional
-from typing import TYPE_CHECKING
-
-from typing_extensions import override
-
+from .context import Context
+# Keep ReadonlyContext for backward compatibility
 from .readonly_context import ReadonlyContext
 
-if TYPE_CHECKING:
-  from google.genai import types
-
-  from ..artifacts.base_artifact_service import ArtifactVersion
-  from ..auth.auth_credential import AuthCredential
-  from ..auth.auth_tool import AuthConfig
-  from ..events.event import Event
-  from ..events.event_actions import EventActions
-  from ..sessions.state import State
-  from .invocation_context import InvocationContext
-
-
-class CallbackContext(ReadonlyContext):
-  """The context of various callbacks within an agent run."""
-
-  def __init__(
-      self,
-      invocation_context: InvocationContext,
-      *,
-      event_actions: Optional[EventActions] = None,
-  ) -> None:
-    super().__init__(invocation_context)
-
-    from ..events.event_actions import EventActions
-    from ..sessions.state import State
-
-    self._event_actions = event_actions or EventActions()
-    self._state = State(
-        value=invocation_context.session.state,
-        delta=self._event_actions.state_delta,
-    )
-
-  @property
-  @override
-  def state(self) -> State:
-    """The delta-aware state of the current session.
-
-    For any state change, you can mutate this object directly,
-    e.g. `ctx.state['foo'] = 'bar'`
-    """
-    return self._state
-
-  async def load_artifact(
-      self, filename: str, version: Optional[int] = None
-  ) -> Optional[types.Part]:
-    """Loads an artifact attached to the current session.
-
-    Args:
-      filename: The filename of the artifact.
-      version: The version of the artifact. If None, the latest version will be
-        returned.
-
-    Returns:
-      The artifact.
-    """
-    if self._invocation_context.artifact_service is None:
-      raise ValueError("Artifact service is not initialized.")
-    return await self._invocation_context.artifact_service.load_artifact(
-        app_name=self._invocation_context.app_name,
-        user_id=self._invocation_context.user_id,
-        session_id=self._invocation_context.session.id,
-        filename=filename,
-        version=version,
-    )
-
-  async def save_artifact(
-      self,
-      filename: str,
-      artifact: types.Part,
-      custom_metadata: Optional[dict[str, Any]] = None,
-  ) -> int:
-    """Saves an artifact and records it as delta for the current session.
-
-    Args:
-      filename: The filename of the artifact.
-      artifact: The artifact to save.
-      custom_metadata: Custom metadata to associate with the artifact.
-
-    Returns:
-     The version of the artifact.
-    """
-    if self._invocation_context.artifact_service is None:
-      raise ValueError("Artifact service is not initialized.")
-    version = await self._invocation_context.artifact_service.save_artifact(
-        app_name=self._invocation_context.app_name,
-        user_id=self._invocation_context.user_id,
-        session_id=self._invocation_context.session.id,
-        filename=filename,
-        artifact=artifact,
-        custom_metadata=custom_metadata,
-    )
-    self._event_actions.artifact_delta[filename] = version
-    return version
-
-  async def get_artifact_version(
-      self, filename: str, version: Optional[int] = None
-  ) -> Optional[ArtifactVersion]:
-    """Gets artifact version info.
-
-    Args:
-      filename: The filename of the artifact.
-      version: The version of the artifact. If None, the latest version will be
-        returned.
-
-    Returns:
-      The artifact version info.
-    """
-    if self._invocation_context.artifact_service is None:
-      raise ValueError("Artifact service is not initialized.")
-    return await self._invocation_context.artifact_service.get_artifact_version(
-        app_name=self._invocation_context.app_name,
-        user_id=self._invocation_context.user_id,
-        session_id=self._invocation_context.session.id,
-        filename=filename,
-        version=version,
-    )
-
-  async def list_artifacts(self) -> list[str]:
-    """Lists the filenames of the artifacts attached to the current session."""
-    if self._invocation_context.artifact_service is None:
-      raise ValueError("Artifact service is not initialized.")
-    return await self._invocation_context.artifact_service.list_artifact_keys(
-        app_name=self._invocation_context.app_name,
-        user_id=self._invocation_context.user_id,
-        session_id=self._invocation_context.session.id,
-    )
-
-  async def save_credential(self, auth_config: AuthConfig) -> None:
-    """Saves a credential to the credential service.
-
-    Args:
-      auth_config: The authentication configuration containing the credential.
-    """
-    if self._invocation_context.credential_service is None:
-      raise ValueError("Credential service is not initialized.")
-    await self._invocation_context.credential_service.save_credential(
-        auth_config, self
-    )
-
-  async def load_credential(
-      self, auth_config: AuthConfig
-  ) -> Optional[AuthCredential]:
-    """Loads a credential from the credential service.
-
-    Args:
-      auth_config: The authentication configuration for the credential.
-
-    Returns:
-      The loaded credential, or None if not found.
-    """
-    if self._invocation_context.credential_service is None:
-      raise ValueError("Credential service is not initialized.")
-    return await self._invocation_context.credential_service.load_credential(
-        auth_config, self
-    )
-
-  def get_auth_response(
-      self, auth_config: AuthConfig
-  ) -> Optional[AuthCredential]:
-    """Gets the auth response credential from session state.
-
-    This method retrieves an authentication credential that was previously
-    stored in session state after a user completed an OAuth flow or other
-    authentication process.
-
-    Args:
-      auth_config: The authentication configuration for the credential.
-
-    Returns:
-      The auth credential from the auth response, or None if not found.
-    """
-    from ..auth.auth_handler import AuthHandler
-
-    return AuthHandler(auth_config).get_auth_response(self.state)
-
-  async def add_session_to_memory(self) -> None:
-    """Triggers memory generation for the current session.
-
-    This method saves the current session's events to the memory service,
-    enabling the agent to recall information from past interactions.
-
-    Raises:
-      ValueError: If memory service is not available.
-
-    Example:
-      ```python
-      async def my_after_agent_callback(callback_context: CallbackContext):
-          # Save conversation to memory at the end of each interaction
-          await callback_context.add_session_to_memory()
-      ```
-    """
-    if self._invocation_context.memory_service is None:
-      raise ValueError(
-          "Cannot add session to memory: memory service is not available."
-      )
-    await self._invocation_context.memory_service.add_session_to_memory(
-        self._invocation_context.session
-    )
-
-  async def add_events_to_memory(
-      self,
-      *,
-      events: Sequence[Event],
-      custom_metadata: Mapping[str, object] | None = None,
-  ) -> None:
-    """Adds an explicit list of events to the memory service.
-
-    Uses this callback's current session identifiers as memory scope.
-
-    Args:
-      events: Explicit events to add to memory.
-      custom_metadata: Optional standard metadata for memory generation.
-
-    Raises:
-      ValueError: If memory service is not available.
-    """
-    if self._invocation_context.memory_service is None:
-      raise ValueError(
-          "Cannot add events to memory: memory service is not available."
-      )
-    await self._invocation_context.memory_service.add_events_to_memory(
-        app_name=self._invocation_context.session.app_name,
-        user_id=self._invocation_context.session.user_id,
-        session_id=self._invocation_context.session.id,
-        events=events,
-        custom_metadata=custom_metadata,
-    )
+# CallbackContext is unified into Context
+CallbackContext = Context