Data ingestion and processing

I'm trying to automate the ingestion of data from Pub/sub to Bigquery. I need help writing a cloud function to subscribe to a pub/sub, do some processing on that data to apply a certain logic, and then insert the data into Bigquery. I intend to use cloud scheduler, cloud pub/sub, cloud functions and big query. Do not intend to use apache beam as the volume of data is very low. (<100 records per day)