[NIFI-9352] Components that reference variable in user-defined property are not stopped/restarted when variable is updated

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 1.15.0
• Fix Version/s: 1.15.0
• Component/s: Core Framework
• Assignee: Mark Payne
• Reporter: Mark Payne
• Created: 30/Oct/21 14:18
• Updated: 30/Oct/21 16:18
• Resolved: 30/Oct/21 16:18

Description

When a Process Group's variable is updated, any component that references that variable must first be stopped and then restarted. However, if a processor references the variable in a user-defined property, it does not get stopped & restarted.

To illustrate:

• Create a GenerateFlowFile processor
• Add a user-defined property if "Hello" with a value of "${greeting}"
• Create a variable named "greeting" in the Process Group and give it any value - say "hello".
• Connect GenerateFlowFile to an UpdateAttribute and set the Run Schedule to "1 hour".
• Start GenerateFlowFile. It should run once.
• Update variable to have a value of "good-bye".
• After changes have been applied, you should have seen GenerateFlowFile run twice - once with a value of "hello" and again with a value of "good-bye" but currently you'll see it have only run once.

As a result, when a variable is change, it may not take effect on all processors until restart of NiFi.

Issue Links

• links to: GitHub Pull Request #5499