feat: ✨ redis session class

[BloodBoy21]

This pull request introduces a Redis-backed session service implementation, along with various enhancements and adjustments to improve consistency, functionality, and maintainability across the codebase. The most significant changes include the addition of the RedisMemorySessionService, updates to the Event and Session classes to support serialization and deserialization, and the inclusion of Redis as a dependency.

New Redis-backed session service:

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

Serialization and deserialization enhancements:

• Added to_dict and from_dict methods to the Event class to enable serialization and deserialization of event objects. (src/google/adk/events/event.py)
• Added to_dict and from_dict methods to the Session class for similar functionality, enabling seamless handling of session data in the Redis service. (src/google/adk/sessions/session.py)

Dependency updates:

• Added redis>=6.0.0 as a new dependency in pyproject.toml to support the Redis-based session service. (pyproject.toml)

Consistency improvements:

• Updated string literals in the Event and Session classes to use double quotes for consistency. (src/google/adk/events/event.py) [1] [2] (src/google/adk/sessions/session.py) [3]

[whhlct]

Any update on the status of this PR?

[boyangsvl]

Hi, we are preparing a new repo to house community contributions which will give more freedom to the community to add new features that extend ADK's features. Please stay tuned.

[semoal]

Hi, we are preparing a new repo to house community contributions which will give more freedom to the community to add new features that extend ADK's features. Please stay tuned.

Hi Bo! Are there any timeline available for that? We would love to add Redis session storage in our services.

[boyangsvl]

@hangfei do you have an ETA for the community repo?

[nmvijay]

@boyangsvl this is very important feature to build scalable agents, it would be great, if we get some conclusion soon.

[boyangsvl]

Sorry for the delay. There are some processes we have to go through to create the repo. Please stay tuned.

[javierherrera1996]

I really need this kind of solution i'm building big project and i need to share my session between many services.

[rajatm91]

@boyangsvl any timelines when this feature would be available

[hangfei]

Hi folks, could you migrate this PR to our community repo: https://github.com/google/adk-python-community. This work fits very well into domain of that repo. If you have any followup questions, feel free to raise them.

[anoteboom]

If this Redis Session service is implemented in this new community repository, how will we use it?
I now start our CloudRun app using get_fast_api_app:

from google.adk.cli.fast_api import get_fast_api_app
app = get_fast_api_app(
    agents_dir=AGENT_DIR,
    session_service_uri=SESSION_SERVICE_URI
)

But this session_service_uri argument does not support a URI like "redis://"

How would that work when the community creates other services?

[boyangsvl]

Hi @anoteboom,

I'm thinking about a registry mechanism that allows people to register a session service to a URI schema. Do you have time to think about such a design?

[yvesemmanuel]

Hi folks. Following the work in this PR, I've implemented a Redis session service for the community repository. Also, a community FastAPI management is also available to support Redis URI:

from google.adk_community.cli.fast_api import get_fast_api_app
app = get_fast_api_app(
    agents_dir=AGENT_DIR,
    session_service_uri="redis://..."
)

I'd appreciate your review and welcome any contributions or feedback: google/adk-python-community#4.