With Postgresql v10 and WAL2JSON... Is it possible to include the database name / datname in the json? We have a set of databases that were not set up in a multi-tenant fashion. Looking to build a hub that will hold the data in a multi-tenant fashion using wal2json to pipe data from source to the hub. With each JSON object, I need to know which database it's coming from. Is this possible?
I don't think this is possible because AFAIK database name or related oid is not stored in JSON columns. But it is always possible to retrieve current database name in a SQL session with:

select current_database();