How to parse the description text in order to fill in the task fields based on it?

Question

JIRA

There is the following task. In JIRA, a task is born from a letter. In the letter, the value of custom fields is transmitted according to a certain rule. How and with what to parse the description text in order to fill in custom fields from it?

Answer 1

Before asking such a question, it would be great to clarify how letters are born now and what version of the jira (cloud/server/dc).
As a slightly perverse option, you can use Automation and fill in the fields by finding the key: value (not the key) in the description. Conditionally, if "priority:blocker" is found, then set the value of the priority field to Blocker.
Of the minuses - you have to do a huge number of conditions.
A little more fun is to parse a freshly created ticket using ScriptRunner and fill in the fields.
The easiest way is to create tickets using the Email This Issue plugin and parse at the time of creation.