How to log the usage token?

[yonax-profitpeak]

I can see the usage token is returned by Gemini API under "usage_metadata". However it is not logged by the DatabaseSessionService and it seems not passed to the yielded events. How to access and log this for each interactions? Currently using v1.8.0 Thanks.

[adk-bot]

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

TLDR: The usage_metadata is not automatically logged because it is not a standard field in the event schema. To log this information, you will need to create a custom event converter to extract the usage_metadata and add it to the event. You can then configure your pipeline to use this custom event converter.

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To log the usage_metadata from the Gemini API, you need to implement a custom event converter. The usage_metadata is not a standard part of the event schema, so the DatabaseSessionService does not log it by default.

Here are the steps to create a custom event converter:

1. Create a new Python file for your custom converter (e.g., my_converters.py).
2. Define a new converter class that inherits from EventConverter.
3. Implement the convert method to extract the usage_metadata and add it to the event.

Here is an example of a custom event converter that extracts the usage_metadata:

from google.adk.a2a.converters.event_converter import EventConverter

class MyEventConverter(EventConverter):
    def convert(self, event: dict) -> dict:
        # Your custom logic to extract usage_metadata
        if "usage_metadata" in event:
            event["usage_metadata"] = event["usage_metadata"]
        return event

After creating your custom converter, you need to configure your ADK pipeline to use it. You can do this by updating your pipeline configuration file (e.g., config.yaml) to include your custom converter.

For more information on creating and using custom plugins, please refer to the ADK documentation on plugins. [1]

We are closing this discussion for now. Please feel free to reopen it if you have any more questions.

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[1] https://google.github.io/adk-docs/plugins/

[DeanChensj]

Hi @yonax-profitpeak , thanks for reporting this, this seems to be an issue that we didn't make the DB session service in consistent with the schema change of the LlmResponse.

We will convert this into an issue.