Pub/Sub to BQ fails to serialize json

[velith]

I am trying to get going with the Dataflow template for Pub/Sub subscription to BigQuery. All of the messages end up in the table for errors records. The stack trace says: "java.lang.RuntimeException: Failed to serialize json to table row" and it fails for the actual message body.

The body of each message is an JSON array like:
[{"itemNo":"00050330","itemType":"Sales","itemDesc":"A Table","quantity":4.0,"extendedAmount":120.0,"orderId":null,"itemGroup":"0421","originalDocumentNo":null}]

Any help would be appreciated!

[velith]

Solved by using an UDF that transforms incoming payload that adds a new field.