Following is a code sample of a dataflow for importing data from SFTP to Gigya. This sample flow includes extracting a CSV file from SFTP, parsing it to DSV, renaming the fields to a format that matches Gigya's database (in this case the fields are several examples of different newsletters), and finally uploading the transformed data into the Gigya account. You can use this flow as a template and change some of the steps in the script: such as extracting a JSON file rather than CSV. Note that datasource.write.gigya.account is the final step, so any transformation to the data, including transforming a string into Boolean or handling empty fields, should be handled in a previous step.
For a full outline of the dataflow steps that are available out of the box, see Script Repository.