I have successfully implemented google assistant on rpi using gassistpi and added agent on dialogflow also. The issue is that if multiple users invoke google assistant on different raspberry pi I am not able to identify which user has invoked the action as request from webhook on dialogflow doesn't have any user identity information. Thus, I am facing issues while retrieving data for particular user.
I tried using account linking on actions on google using google signup over voice but I am unable to implement that.
The Google Assistant SDK does not have voice match as a feature, so you would be unable to use it to identify individual users of the Action on that surface.
check identity of multiple users on actions on google