[DRILL-7590] Refactor plugin registry

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.17.0
• Fix Version/s: 1.18.0
• Labels: ready-to-commit
• Assignee: Paul Rogers
• Reporter: Paul Rogers
• Reviewer: Arina Ielchiieva
• Created: 17/Feb/20 18:51
• Updated: 28/Dec/23 14:37
• Resolved: 02/Mar/20 15:04

Description

The plugin registry connects configurations, stored in ZK, with implementations, which are Java classes. The registry handles a large number of tasks including:

• Populating "bootstrap" plugin configurations and handling upgrades.
• Reading from, and writing to, the persistent store in ZK.
• Handling "normal" (configured) plugins and special system plugins (which have no configuration.)
• Handle format plugins which are always associated with the DFS storage plugin.
• And so on.

The code has grown overly complex. As we look to add a new, cleaner plugin mechanism, we will start by cleaning up what we have to allow the new mechanism to be one of many.

Issue Links

• causes: DRILL-8468 Drill doesn't perform drill.exec.storage.action_on_plugins_override_file action
• links to: GitHub Pull Request #1988