Using project role in post function to fill custom field

unknown

How can I get a custom field to autofill with the project role using post functions in a workflow?

For example, when I create an issue I would like the merchandiser custom field (userpicker) to be filled by the merchandiser project role in that project as these are normally the same person. However these could then be altered and it will use the merchandiser custom field throughout the rest of the workflow.

Not sure how easy this is to follow...

Alexey_Rjeutski__Polontech_

There is no easy option for onDemand. For standalone I would recommend you to use the https://jamieechlin.atlassian.net/wiki/display/GRV/Post+Functions script runner postfunction, as for the onDemand - it is possible either to write a separate application that will use JIRA REST API https://docs.atlassian.com/jira/REST/latest/ (search for recently updated tickets and change custom field according to that) and be running with cron or some scheduler periodically either to write a plugin using atlassian connect https://developer.atlassian.com/static/connect/docs/index.html