Handling next page token in VertexAISessionService list sessions response

[mdailey]

Hello everyone,

I am working on an ADK agent that makes use of the VertexAISessionService. In adk-python, this service is represented by class VertexAiSessionService, which has a method list_sessions that retrieves a list of sessions from the Agent Engine reasoning engine, filtered by user ID.

The documentation for the reasoning engine list sessions API endpoint says that the session list may contain a nextPageToken if the list of sessions is long.

However, the list_sessions method of the adk-python wrapper for this endpoint seems to ignore the possibility of a long paginated session list.

My question is whether there is a valid reason for this, such as some inside knowledge that Agent Engine will never paginate the resulting session list? If not, this could be a problem as we move our agent into production, so I might contribute a PR.

Matt

[adk-bot]

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

TLDR: You are correct, the list_sessions method in VertexAiSessionService does not currently handle pagination. This appears to be an oversight, and a pull request to add this functionality would be a welcome contribution.

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Hi Matt,

Thank you for your careful analysis and for bringing this to our attention.

You are correct that the list_sessions method in the VertexAiSessionService does not currently handle the nextPageToken for paginated responses from the Vertex AI Reasoning Engine API. [1]

As you noted, this could indeed be an issue for applications with a large number of sessions. While we don't have specific "inside knowledge" suggesting that the API will never paginate this list, we can see that other parts of the service, such as the get_session method for retrieving session events, do handle pagination. This suggests that its absence in list_sessions is likely an oversight rather than an intentional design choice.

We would welcome a pull request from you to add this functionality. Your contribution would be valuable in making the ADK more robust for production use cases.

Thank you again for your sharp eye and willingness to contribute!

[1] https://github.com/google/adk-python/blob/main/src/google/adk/sessions/vertex_ai_session_service.py

[ankursharmas]

I have created an issue for this #2860

I am going to close this, as any discussion on this topic should happen in the ticket.