The easiest way to run would be to build the docker image:
$ docker build -t dataapi .
Then run it:
$ docker run -p 8000:80 -e CONNECTION_STRING='connection string' dataapi
You can now open the browser to http://localhost:8000/graphql to get the interactive GUI. The same endpoint listens to the POST requests.
CONNECTION_STRING must point to the Survey Solutions database.
dataapi reads interviews directly from the database, but still requires the export to be run. So interiews only become available through GraphQL API only if there is a generated export (in any format).
Query fields for each questionnaire in ALL workspaces are presented, they are labeled as workspace_questionnaire.var_version