How to de-identify data before logging to BigQuery Table

[Yogender]

Hi Everyone, 

Could anyone help me on how can I de-identify PII ( Personal information like Credit Card number) before getting logged to big Query table . 

I have been thinking of creating a pub/sub topic to get triggered on every conversation request which will trigger a cloud function for de-identifying the user and agent Utterances  and insert to BigQuery Table , but unable to find a way to trigger event on every conversation. 

Please provide any resources or documents or the same. 

Thanks.