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Spring Boot Actuator

Spring Boot includes a number of additional features to help you monitor and manage your application. The spring-boot-actuator module provides all of Spring Boot’s production-ready features.

Let’s start creating a new Spring Boot project with web and actuator dependencies:

spring init --dependencies=web,actuator --language=groovy --build=gradle spring-boot-actuator

This is the build.gradle file generated:

buildscript {
  ext {
    springBootVersion = '1.5.12.RELEASE'
  }
  repositories {
    mavenCentral()
  }
  dependencies {
    classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
  }
}

apply plugin: 'groovy'
apply plugin: 'org.springframework.boot'

group = 'com.jos.dem.springboot.actuator'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
  mavenCentral()
}

dependencies {
  compile('org.springframework.boot:spring-boot-starter-web')
  compile('org.springframework.boot:spring-boot-starter-actuator')
  compile('org.codehaus.groovy:groovy')
  testCompile('org.springframework.boot:spring-boot-starter-test')
}

Now, let’s create a RestController

package com.jos.dem.springboot.actuator

import org.springframework.web.bind.annotation.RestController
import org.springframework.web.bind.annotation.RequestMapping

@RestController
class DemoController {

  @RequestMapping("/")
  String index(){
    'Hello World!'
  }

}

At this point you have an application Spring Boot running. Execute this command in order to see the Hello World message in http://localhost:8080/

gradle bootRun

Spring Boot Actuator enable you to monitor and manage your application, usually using HTTP end-points. You can monitor in terms of memory, uptime, threads, environment variables, beans created and more. Spring Boot Actuator defaults run on port 8080 as well. Let’s change this in our application.properties file.

management.port: 9090
management.address: 127.0.0.1

By default Actuator end-points are protected by Spring Security.

{
  "timestamp": 1516053662310,
  "status": 401,
  "error": "Unauthorized",
  "message": "Full authentication is required to access this resource.",
  "path": "/metrics"
}

Let’s deactivate Spring Security in order to simplify this example, to disable this you need to add this line in our application.properties file:

management.port: 9090
management.address: 127.0.0.1
management.security.enabled=false

After that changes let’s run again our application

gradle bootRun

Now we are able to hit some Actuator’s endpoints such as:

For a complete list please visit this official documentation: Actuator Endpoints

For example in metrics we can get this kind of information:

{
  "mem": 296427,
  "mem.free": 206593,
  "processors": 4,
  "instance.uptime": 261456,
  "uptime": 270593,
  "systemload.average": -1,
  "heap.committed": 241664,
  "heap.init": 129024,
  "heap.used": 35070,
  "heap": 1815040,
  "nonheap.committed": 55784,
  "nonheap.init": 2496,
  "nonheap.used": 54765,
  "nonheap": 0,
  "threads.peak": 43,
  "threads.daemon": 36,
  "threads.totalStarted": 46,
  "threads": 39,
  "classes": 6499,
  "classes.loaded": 6499,
  "classes.unloaded": 0,
  "gc.ps_scavenge.count": 8,
  "gc.ps_scavenge.time": 143,
  "gc.ps_marksweep.count": 2,
  "gc.ps_marksweep.time": 225,
  "httpsessions.max": -1,
  "httpsessions.active": 0
}

We can add custom metrics, let’s count how many times we are calling index method from our DemoController

package com.jos.dem.springboot.actuator

import org.springframework.web.bind.annotation.RestController
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.boot.actuate.metrics.CounterService
import org.springframework.beans.factory.annotation.Autowired

@RestController
class DemoController {

  @Autowired
  CounterService counterService

  @RequestMapping("/")
  String index(){
  	counterService.increment("com.jos.dem.springboot.actuator.DemoController.index");
    'Hello World!'
  }

}

Now we can get this metrics version:

{
  "mem": 296604,
  "mem.free": 203770,
  "processors": 4,
  "instance.uptime": 448569,
  "uptime": 457707,
  "systemload.average": -1,
  "heap.committed": 241664,
  "heap.init": 129024,
  "heap.used": 37893,
  "heap": 1815040,
  "nonheap.committed": 56104,
  "nonheap.init": 2496,
  "nonheap.used": 54940,
  "nonheap": 0,
  "threads.peak": 43,
  "threads.daemon": 36,
  "threads.totalStarted": 46,
  "threads": 39,
  "classes": 6520,
  "classes.loaded": 6520,
  "classes.unloaded": 0,
  "gc.ps_scavenge.count": 8,
  "gc.ps_scavenge.time": 143,
  "gc.ps_marksweep.count": 2,
  "gc.ps_marksweep.time": 225,
  "httpsessions.max": -1,
  "httpsessions.active": 0,
  "gauge.response.root": 36,
  "counter.status.200.root": 1,
  "counter.com.jos.dem.springboot.actuator.DemoController.index": 1
}

To download project:

git clone https://github.com/josdem/spring-boot-actuator.git

To run project:

gradle bootRun

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