Deleting user and app state

[Ponts]

Hi!
I am implementing deleting users from my program which uses VertexAISessionService.
I have noticed that after deleting all sessions for the user, and creating the user again, that the user prefixed state remains.
Is it possible to clear the user state with some request? The closest thing I have thought of is getting the state from a session, checking all the keys and sending a Event to the session service to set them to null.

Is there a better way?

[adk-bot]

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: You are correct, deleting all of a user's sessions will not automatically clear the user: prefixed state. The recommended way to clear the user state is to manually send an Event with a state_delta that sets the desired user:* keys to null.

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Hi! That's a great question, and your understanding of the situation is spot on.

In the Agent Development Kit (ADK), conversational context is managed through Session, State, and Memory. [6] The State is a key-value store that can be scoped to the current session (no prefix), the user ( user: prefix), or the application (app: prefix). [2, 10]

As you've observed, the user: prefixed state is designed to persist across all sessions for a specific user, even after individual sessions are deleted. [10] This is to maintain user preferences and context over time. The delete_session function, whether you're using VertexAiSessionService or another session service, is only responsible for deleting a single session and its associated session-specific state. [8, 11, 21]

Therefore, your proposed solution of manually clearing the state is the correct and intended way to handle this. There isn't a single built-in function like delete_user_state.

Here's a more detailed breakdown of how you could implement this:

1. Create a temporary session for the user whose state you want to clear.
2. Get the session object. The session.state attribute will contain the merged state, including all the user:* key-value pairs.
3. Identify the user-specific keys you want to clear from the session.state.
4. Create a state_delta dictionary. In this dictionary, set the value of each of the user:* keys to None.
5. Append a new Event to the temporary session, including your state_delta in the EventActions. This will update the persistent user state, effectively clearing it.
6. (Optional) Delete the temporary session.

This method ensures that the user's state is properly cleared in a way that is consistent with ADK's state management design.

I am a bot that helps answer questions about ADK. If you have any further questions, please don't hesitate to ask!

[Ponts]

In my code I can use vertex ai client directly. Do you know of a way to do it without involving adk?
I have implemented the workaround for now but i would prefer there to be a built in function