[NIFI-5373] Create Metrics API and default implementation

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0
• Fix Version/s: 1.10.0
• Component/s: Core Framework
• Labels: Java11
• Assignee: Jeff Storck
• Reporter: Jeff Storck
• Created: 03/Jul/18 19:38
• Updated: 20/Feb/20 17:28
• Resolved: 19/Jun/19 19:57

Description

A decoupling of the metrics library used by several reporting components by providing a similar API in the nifi-api module (under a new package org.apache.nifi.metrics.jvm) will help internalize the dependencies on the yammer/dropwizard metrics libraries and reduce the number of dependencies that NiFi extensions need to collect those types of metrics.

While working towards support for building NiFi on Java 10+, tests for components that use the com.yammer.metrics:metrics-core:2.2.0 dependency are failing due to references to internal JDK modules.  These metrics libraries are now maintained dropwizard, and a new version (4.0.0) has been released that works with Java 10.

The public API for the metrics libraries has changed a bit, and VirtualMachineMetrics is no longer available.  NiFi will supply its own public API for metrics that is derived from dropwizard/yammer's VirtualMachineMetrics to minimize impact to NiFi extensions that currently use this dependency.

Issue Links

• blocks: NIFI-5176 NiFi needs to be buildable on Java 11
• causes: NIFI-7173 NoClassDefFoundError: org/apache/nifi/metrics/jvm/JmxJvmMetrics
• relates to: NIFI-611 Add additional metrics to those reported by NiFi
• links to: GitHub Pull Request #3520
• links to: https://github.com/apache/nifi/pull/3404