feat: Add Redis-backed session service to ADK community extensions

[yvesemmanuel]

Redis Session Service Implementation

This pull request addresses the issue described in #5.

This PR migrates the Redis-backed session service implementation proposed in google/adk-python#789. I've excluded the changes to the Event and Session classes, opting to use Pydantic's default serialization and deserialization methods instead. While credit goes to the original pull request from the main repository, I have completely refactored the implementation to align with this community repository's standards.

What's Changed

New Redis-backed session service:

• Added a new RedisMemorySessionService class that provides a Redis-backed implementation of session management, including methods for creating, retrieving, listing, and deleting sessions, as well as managing session state and events (src/google/adk_community/sessions/redis_memory_session_service.py)
• Updated __init__.py in the sessions module to include RedisMemorySessionService in the exports (src/google/adk_community/sessions/__init__.py)

FastAPI CLI integration:

• Added FastAPI CLI module to support Redis session service integration (src/google/adk_community/cli/fast_api.py)
• I needed to move the browser/ dependencies dir for the dev-ui/ endpoint web rendering.

Dependency updates:

• Added redis>=5.0.0, <6.0.0 as a new dependency in pyproject.toml to support the Redis-based session service
• Added development dependencies for testing: pytest>=8.2.2 and pytest-asyncio>=0.23.7

Project infrastructure:

• Added comprehensive .gitignore file for Python projects with IDE, testing, and build artifacts exclusions
• Added unit tests for the Redis session service (tests/unittests/sessions/test_redis_session_service.py)

Testing

Test Setup and Dependencies

The implementation has been thoroughly tested using the academic-research sample from https://github.com/google/adk-samples/tree/main/python/agents/academic-research.

Installation:

pip install git+https://github.com/yvesemmanuel/adk-python-community.git@feature/redis-session-service

Test Implementation

The following FastAPI implementation demonstrates the Redis database session service integration:

import os
import uvicorn
from fastapi import FastAPI
from google.adk_community.cli.fast_api import get_fast_api_app

AGENT_DIR = os.path.dirname(os.path.abspath(__file__)) + "/agents"
SESSION_SERVICE_URI = "redis://127.0.0.1:6379/0"
ALLOWED_ORIGINS = ["http://localhost", "http://localhost:8080", "*"]
SERVE_WEB_INTERFACE = True
ARTIFACT_SERVICE_URI = ""

app: FastAPI = get_fast_api_app(
    agents_dir=AGENT_DIR,
    session_service_uri=SESSION_SERVICE_URI,
    session_db_kwargs=dict(expire=60 * 60 * 1), # 1 hour of Time To Live
    artifact_service_uri=ARTIFACT_SERVICE_URI,
    allow_origins=ALLOWED_ORIGINS,
    web=SERVE_WEB_INTERFACE,
)

@app.get("/health")
async def get_health():
    return {"status": "ok"}

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("PORT", 8080)))

Test Results and Verification

The testing process validates both the web interface functionality and Redis data persistence:

Web Interface Testing

The web UI successfully demonstrates conversation functionality with the academic research agent, confirming that:

• User interactions are properly handled through the FastAPI interface

Redis Data Persistence Verification

Redis Insight shows the successfully written session data and conversation history, confirming that:

• Session data is correctly serialized and stored in Redis
• Conversation history is properly maintained across requests
• Data structure aligns with expected Redis key-value patterns

[google-cla]

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[gemini-code-assist]

Summary of Changes

Hello @yvesemmanuel, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the ADK community extensions by introducing a robust Redis-backed session service. This new service provides a scalable and persistent solution for managing user sessions and their associated states, moving away from in-memory solutions for more demanding applications. The changes include core service implementation, integration with the existing FastAPI CLI, necessary dependency updates, and thorough unit testing to ensure reliability.

Highlights

• New Redis-backed Session Service: Introduced RedisMemorySessionService for persistent session management, offering methods for creating, retrieving, listing, and deleting sessions, as well as managing session state and events.
• FastAPI CLI Integration: Integrated the new Redis session service into the FastAPI CLI module, allowing redis:// URIs for session service configuration.
• Dependency Updates: Added redis>=6.0.0 as a core dependency and pytest>=8.4.2 and pytest-asyncio>=1.2.0 as development dependencies for testing.
• Project Infrastructure: Added a comprehensive .gitignore file for Python projects and included unit tests for the new Redis session service.

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[gemini-code-assist]

Code Review

This pull request introduces a Redis-backed session service, which is a valuable addition for enabling persistent session management in the ADK. The implementation is generally solid, with good use of async Redis operations and a comprehensive set of unit tests. However, I've identified a few critical issues with dependency versions that will prevent the package from being installed or the development environment from being set up. I also have a significant concern regarding the scalability of the current Redis storage strategy, which could lead to performance problems in production. Additionally, there are several opportunities to improve code clarity, efficiency, and test coverage. My detailed comments are provided below.

[yvesemmanuel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a valuable Redis-backed session service. The overall structure is sound, leveraging redis-py for asynchronous operations and providing a clear API. However, I've identified several critical issues related to performance and correctness in the session management logic. The current implementation inefficiently loads and saves all of a user's sessions for operations that should only affect a single session, which can lead to significant performance degradation and race conditions under concurrent use. I have provided specific, refactored code suggestions for each affected method to resolve these issues by using atomic, single-key Redis operations. Additionally, there is a critical bug in src/google/adk_community/__init__.py that will prevent the package from being imported, and some of the new unit tests use incorrect mocking, which I've also flagged for correction. Addressing these points will make the new service robust, performant, and reliable.

[yvesemmanuel]

/gemini review

[gemini-code-assist]

Code Review

This pull request is a great addition, introducing a Redis-backed session service for more robust session management. The implementation is solid, effectively using Redis features like pipelines and expiration. The tests are comprehensive and cover the new functionality well. I've identified a few areas for improvement related to code quality, performance, and a potential bug in a utility function. My detailed comments are provided below.

[yvesemmanuel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a Redis-backed session service, which is a great addition for more persistent session management. The implementation is solid and includes comprehensive unit tests. I've found a critical issue regarding argument handling in the service's constructor that would cause a crash, and a high-severity issue with the use of asyncio.run() in the synchronous helper methods. I've also included a couple of medium-severity suggestions for code quality and performance improvement. Overall, great work on this feature.

[yvesemmanuel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a Redis-backed session service, which is a valuable addition for enabling persistent sessions in ADK applications. The implementation is well-structured, using Redis pipelines for efficiency and including a good set of unit tests. I've identified a couple of areas for improvement related to data consistency with key expirations and the cleanup of stale session IDs. My review comments provide specific suggestions to enhance the robustness of the new service. Overall, this is a solid contribution.

[yvesemmanuel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a Redis-backed session service, which is a valuable addition for enabling scalable session management. The implementation is solid, effectively using Redis pipelines for efficiency and atomicity. The code is well-structured, and the inclusion of unit tests is commendable. My review provides feedback on a few areas for improvement, focusing on code clarity, best practices, and test correctness to further enhance the quality of this new feature.

[boyangsvl]

@hangfei could you help review? I wonder which folder these files should live. We probably shouldn't have 'google' in the path.

[danielefranceschi]

What is the right way to pass authentication parameters to the RedisMemorySessionService constructor?

I've tried uri="redis://mypassword@myhost:6379/" and all the possible combinations with kwargs following the redis documentation, but nothing.

[yvesemmanuel]

redis://127.0.0.1:6379/0

Here I'm following this pattern for the URI: redis[s]://[[username][:password]@][host][:port][/db-number].

[hangfei]

Removed JS code for now. Overall LGTM.

[DeanChensj]

Shall we use keyword arguments to be more clear?

[hangfei]

seems other session impls also not using it.

any reason we are not using it there?