Monitoring Java Spring Boot Applications

Netdata can be used to monitor running Java Spring Boot applications that expose their metrics with the use of the Spring Boot Actuator included in Spring Boot library.

The Spring Boot Actuator exposes these metrics over HTTP and is very easy to use:

• add org.springframework.boot:spring-boot-starter-actuator to your application dependencies
• set endpoints.metrics.sensitive=false in your application.properties

You can create custom Metrics by add and inject a PublicMetrics in your application. This is a example to add custom metrics:

package com.example;

import org.springframework.boot.actuate.endpoint.PublicMetrics;
import org.springframework.boot.actuate.metrics.Metric;
import org.springframework.stereotype.Service;

import java.lang.management.ManagementFactory;
import java.lang.management.MemoryPoolMXBean;
import java.util.ArrayList;
import java.util.Collection;

@Service
public class HeapPoolMetrics implements PublicMetrics {

    private static final String PREFIX = "mempool.";
    private static final String KEY_EDEN = PREFIX + "eden";
    private static final String KEY_SURVIVOR = PREFIX + "survivor";
    private static final String KEY_TENURED = PREFIX + "tenured";

    @Override
    public Collection<Metric<?>> metrics() {
        Collection<Metric<?>> result = new ArrayList<>(4);
        for (MemoryPoolMXBean mem : ManagementFactory.getMemoryPoolMXBeans()) {
            String poolName = mem.getName();
            String name = null;
            if (poolName.indexOf("Eden Space") != -1) {
                name = KEY_EDEN;
            } else if (poolName.indexOf("Survivor Space") != -1) {
                name = KEY_SURVIVOR;
            } else if (poolName.indexOf("Tenured Gen") != -1 || poolName.indexOf("Old Gen") != -1) {
                name = KEY_TENURED;
            }

            if (name != null) {
                result.add(newMemoryMetric(name, mem.getUsage().getMax()));
                result.add(newMemoryMetric(name + ".init", mem.getUsage().getInit()));
                result.add(newMemoryMetric(name + ".committed", mem.getUsage().getCommitted()));
                result.add(newMemoryMetric(name + ".used", mem.getUsage().getUsed()));
            }
        }
        return result;
    }

    private Metric<Long> newMemoryMetric(String name, long bytes) {
        return new Metric<>(name, bytes / 1024);
    }
}

Please refer Spring Boot Actuator: Production-ready features and 81. Actuator - Part IX. ‘How-to’ guides for more information.

Using netdata springboot module

The springboot module is enabled by default. It looks up http://localhost:8080/metrics and http://127.0.0.1:8080/metrics to detect Spring Boot application by default. You can change it by editing /etc/netdata/python.d/springboot.conf (to edit it on your system run /etc/netdata/edit-config python.d/springboot.conf).

This module defines some common charts, and you can add custom charts by change the configurations.

The configuration format is like:

<id>:
  name: '<name>'
  url:  '<metrics endpoint>' # ex. http://localhost:8080/metrics
  user: '<username>'         # optional
  pass: '<password>'         # optional
  defaults:
    [<chart-id>]: true|false
  extras:
  - id: '<chart-id>'
    options:
      title:  '***'
      units:  '***'
      family: '***'
      context: 'springboot.***'
      charttype: 'stacked' | 'area' | 'line'
    lines:
    - { dimension: 'myapp_ok',  name: 'ok',  algorithm: 'absolute', multiplier: 1, divisor: 1} # it shows "myapp.ok" metrics
    - { dimension: 'myapp_ng',  name: 'ng',  algorithm: 'absolute', multiplier: 1, divisor: 1} # it shows "myapp.ng" metrics

By default, it creates response_code, threads, gc_time, gc_ope abd heap charts. You can disable the default charts by set defaults.<chart-id>: false.

The dimension name of extras charts should replace . to _.

Please check springboot.conf for more examples.