[NIFI-7130] Change FlowController and StandardFlowService to use interfaces and allow injection

• Type: Improvement
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.11.1
• Component/s: Core Framework
• Labels: dependency-injection inversion-of-control refactoring
• Epic Link: Improve secure hasher architecture
• Assignee: Unassigned
• Reporter: Andy LoPresto
• Created: 10/Feb/20 23:43
• Updated: 10/Feb/20 23:43

Description

The FlowController and StandardFlowService classes are critical components in the NiFi controller which require a number of collaborator services but create these classes internally and do not allow for dependency injection or inversion of control. This makes them nearly impossible to coherently unit test, and they are very brittle and tightly coupled to specific implementations.

Introducing interfaces and allowing for dependency injection would greatly improve the testability and composition of these classes.