Supported Metrics and Meters

Spring Boot provides automatic meter registration for a wide variety of technologies. In most situations, the defaults provide sensible metrics that can be published to any of the supported monitoring systems.

JVM Metrics

Auto-configuration enables JVM Metrics by using core Micrometer classes. JVM metrics are published under the jvm. meter name.

The following JVM metrics are provided:

  • Various memory and buffer pool details

  • Statistics related to garbage collection

  • Thread utilization

  • The number of classes loaded and unloaded

  • JVM version information

  • JIT compilation time

System Metrics

Auto-configuration enables system metrics by using core Micrometer classes. System metrics are published under the system., process., and disk. meter names.

The following system metrics are provided:

  • CPU metrics

  • File descriptor metrics

  • Uptime metrics (both the amount of time the application has been running and a fixed gauge of the absolute start time)

  • Disk space available

Application Startup Metrics

Auto-configuration exposes application startup time metrics:

  • application.started.time: time taken to start the application.

  • application.ready.time: time taken for the application to be ready to service requests.

Metrics are tagged by the fully qualified name of the application class.

Logger Metrics

Auto-configuration enables the event metrics for both Logback and Log4J2. The details are published under the log4j2.events. or logback.events. meter names.

Task Execution and Scheduling Metrics

Auto-configuration enables the instrumentation of all available ThreadPoolTaskExecutor and ThreadPoolTaskScheduler beans, as long as the underling ThreadPoolExecutor is available. Metrics are tagged by the name of the executor, which is derived from the bean name.

Spring MVC Metrics

Auto-configuration enables the instrumentation of all requests handled by Spring MVC controllers and functional handlers. By default, metrics are generated with the name, http.server.requests. You can customize the name by setting the management.observations.http.server.requests.name property.

See the Spring Framework reference documentation for more information on produced observations.

To add to the default tags, provide a @Bean that extends DefaultServerRequestObservationConvention from the org.springframework.http.server.observation package. To replace the default tags, provide a @Bean that implements ServerRequestObservationConvention.

In some cases, exceptions handled in web controllers are not recorded as request metrics tags. Applications can opt in and record exceptions by setting handled exceptions as request attributes.

By default, all requests are handled. To customize the filter, provide a @Bean that implements FilterRegistrationBean<WebMvcMetricsFilter>.

Spring WebFlux Metrics

Auto-configuration enables the instrumentation of all requests handled by Spring WebFlux controllers and functional handlers. By default, metrics are generated with the name, http.server.requests. You can customize the name by setting the management.observations.http.server.requests.name property.

See the Spring Framework reference documentation for more information on produced observations.

To add to the default tags, provide a @Bean that extends DefaultServerRequestObservationConvention from the org.springframework.http.server.reactive.observation package. To replace the default tags, provide a @Bean that implements ServerRequestObservationConvention.

In some cases, exceptions handled in controllers and handler functions are not recorded as request metrics tags. Applications can opt in and record exceptions by setting handled exceptions as request attributes.

Jersey Server Metrics

Auto-configuration enables the instrumentation of all requests handled by the Jersey JAX-RS implementation. By default, metrics are generated with the name, http.server.requests. You can customize the name by setting the management.observations.http.server.requests.name property.

By default, Jersey server metrics are tagged with the following information:

Tag Description

exception

The simple class name of any exception that was thrown while handling the request.

method

The request’s method (for example, GET or POST)

outcome

The request’s outcome, based on the status code of the response. 1xx is INFORMATIONAL, 2xx is SUCCESS, 3xx is REDIRECTION, 4xx is CLIENT_ERROR, and 5xx is SERVER_ERROR

status

The response’s HTTP status code (for example, 200 or 500)

uri

The request’s URI template prior to variable substitution, if possible (for example, /api/person/{id})

To customize the tags, provide a @Bean that implements JerseyTagsProvider.

HTTP Client Metrics

Spring Boot Actuator manages the instrumentation of both RestTemplate and WebClient. For that, you have to inject the auto-configured builder and use it to create instances:

  • RestTemplateBuilder for RestTemplate

  • WebClient.Builder for WebClient

You can also manually apply the customizers responsible for this instrumentation, namely ObservationRestTemplateCustomizer and ObservationWebClientCustomizer.

By default, metrics are generated with the name, http.client.requests. You can customize the name by setting the management.observations.http.client.requests.name property.

See the Spring Framework reference documentation for more information on produced observations.

To customize the tags when using RestTemplate, provide a @Bean that implements ClientRequestObservationConvention from the org.springframework.http.client.observation package. To customize the tags when using WebClient, provide a @Bean that implements ClientRequestObservationConvention from the org.springframework.web.reactive.function.client package.

Tomcat Metrics

Auto-configuration enables the instrumentation of Tomcat only when an MBeanRegistry is enabled. By default, the MBeanRegistry is disabled, but you can enable it by setting server.tomcat.mbeanregistry.enabled to true.

Tomcat metrics are published under the tomcat. meter name.

Cache Metrics

Auto-configuration enables the instrumentation of all available Cache instances on startup, with metrics prefixed with cache. Cache instrumentation is standardized for a basic set of metrics. Additional, cache-specific metrics are also available.

The following cache libraries are supported:

  • Cache2k

  • Caffeine

  • Hazelcast

  • Any compliant JCache (JSR-107) implementation

  • Redis

Metrics are tagged by the name of the cache and by the name of the CacheManager, which is derived from the bean name.

Only caches that are configured on startup are bound to the registry. For caches not defined in the cache’s configuration, such as caches created on the fly or programmatically after the startup phase, an explicit registration is required. A CacheMetricsRegistrar bean is made available to make that process easier.

Spring GraphQL Metrics

See the Spring GraphQL reference documentation.

DataSource Metrics

Auto-configuration enables the instrumentation of all available DataSource objects with metrics prefixed with jdbc.connections. Data source instrumentation results in gauges that represent the currently active, idle, maximum allowed, and minimum allowed connections in the pool.

Metrics are also tagged by the name of the DataSource computed based on the bean name.

By default, Spring Boot provides metadata for all supported data sources. You can add additional DataSourcePoolMetadataProvider beans if your favorite data source is not supported. See DataSourcePoolMetadataProvidersConfiguration for examples.

Also, Hikari-specific metrics are exposed with a hikaricp prefix. Each metric is tagged by the name of the pool (you can control it with spring.datasource.name).

Hibernate Metrics

If org.hibernate.orm:hibernate-micrometer is on the classpath, all available Hibernate EntityManagerFactory instances that have statistics enabled are instrumented with a metric named hibernate.

Metrics are also tagged by the name of the EntityManagerFactory, which is derived from the bean name.

To enable statistics, the standard JPA property hibernate.generate_statistics must be set to true. You can enable that on the auto-configured EntityManagerFactory:

  • Properties

  • YAML

spring.jpa.properties[hibernate.generate_statistics]=true
spring:
  jpa:
    properties:
      "[hibernate.generate_statistics]": true

Spring Data Repository Metrics

Auto-configuration enables the instrumentation of all Spring Data Repository method invocations. By default, metrics are generated with the name, spring.data.repository.invocations. You can customize the name by setting the management.metrics.data.repository.metric-name property.

The @Timed annotation from the io.micrometer.core.annotation package is supported on Repository interfaces and methods. If you do not want to record metrics for all Repository invocations, you can set management.metrics.data.repository.autotime.enabled to false and exclusively use @Timed annotations instead.

A @Timed annotation with longTask = true enables a long task timer for the method. Long task timers require a separate metric name and can be stacked with a short task timer.

By default, repository invocation related metrics are tagged with the following information:

Tag Description

repository

The simple class name of the source Repository.

method

The name of the Repository method that was invoked.

state

The result state (SUCCESS, ERROR, CANCELED, or RUNNING).

exception

The simple class name of any exception that was thrown from the invocation.

To replace the default tags, provide a @Bean that implements RepositoryTagsProvider.

RabbitMQ Metrics

Auto-configuration enables the instrumentation of all available RabbitMQ connection factories with a metric named rabbitmq.

Spring Integration Metrics

Spring Integration automatically provides Micrometer support whenever a MeterRegistry bean is available. Metrics are published under the spring.integration. meter name.

Kafka Metrics

Auto-configuration registers a MicrometerConsumerListener and MicrometerProducerListener for the auto-configured consumer factory and producer factory, respectively. It also registers a KafkaStreamsMicrometerListener for StreamsBuilderFactoryBean. For more detail, see the Micrometer Native Metrics section of the Spring Kafka documentation.

MongoDB Metrics

This section briefly describes the available metrics for MongoDB.

MongoDB Command Metrics

Auto-configuration registers a MongoMetricsCommandListener with the auto-configured MongoClient.

A timer metric named mongodb.driver.commands is created for each command issued to the underlying MongoDB driver. Each metric is tagged with the following information by default:

Tag Description

command

The name of the command issued.

cluster.id

The identifier of the cluster to which the command was sent.

server.address

The address of the server to which the command was sent.

status

The outcome of the command (SUCCESS or FAILED).

To replace the default metric tags, define a MongoCommandTagsProvider bean, as the following example shows:

  • Java

  • Kotlin

import io.micrometer.core.instrument.binder.mongodb.MongoCommandTagsProvider;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration(proxyBeanMethods = false)
public class MyCommandTagsProviderConfiguration {

	@Bean
	public MongoCommandTagsProvider customCommandTagsProvider() {
		return new CustomCommandTagsProvider();
	}

}
import io.micrometer.core.instrument.binder.mongodb.MongoCommandTagsProvider
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration

@Configuration(proxyBeanMethods = false)
class MyCommandTagsProviderConfiguration {

	@Bean
	fun customCommandTagsProvider(): MongoCommandTagsProvider? {
		return CustomCommandTagsProvider()
	}

}

To disable the auto-configured command metrics, set the following property:

  • Properties

  • YAML

management.metrics.mongo.command.enabled=false
management:
  metrics:
    mongo:
      command:
        enabled: false

MongoDB Connection Pool Metrics

Auto-configuration registers a MongoMetricsConnectionPoolListener with the auto-configured MongoClient.

The following gauge metrics are created for the connection pool:

  • mongodb.driver.pool.size reports the current size of the connection pool, including idle and and in-use members.

  • mongodb.driver.pool.checkedout reports the count of connections that are currently in use.

  • mongodb.driver.pool.waitqueuesize reports the current size of the wait queue for a connection from the pool.

Each metric is tagged with the following information by default:

Tag Description

cluster.id

The identifier of the cluster to which the connection pool corresponds.

server.address

The address of the server to which the connection pool corresponds.

To replace the default metric tags, define a MongoConnectionPoolTagsProvider bean:

  • Java

  • Kotlin

import io.micrometer.core.instrument.binder.mongodb.MongoConnectionPoolTagsProvider;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration(proxyBeanMethods = false)
public class MyConnectionPoolTagsProviderConfiguration {

	@Bean
	public MongoConnectionPoolTagsProvider customConnectionPoolTagsProvider() {
		return new CustomConnectionPoolTagsProvider();
	}

}
import io.micrometer.core.instrument.binder.mongodb.MongoConnectionPoolTagsProvider
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration

@Configuration(proxyBeanMethods = false)
class MyConnectionPoolTagsProviderConfiguration {

	@Bean
	fun customConnectionPoolTagsProvider(): MongoConnectionPoolTagsProvider {
		return CustomConnectionPoolTagsProvider()
	}

}

To disable the auto-configured connection pool metrics, set the following property:

  • Properties

  • YAML

management.metrics.mongo.connectionpool.enabled=false
management:
  metrics:
    mongo:
      connectionpool:
        enabled: false

Jetty Metrics

Auto-configuration binds metrics for Jetty’s ThreadPool by using Micrometer’s JettyServerThreadPoolMetrics. Metrics for Jetty’s Connector instances are bound by using Micrometer’s JettyConnectionMetrics and, when server.ssl.enabled is set to true, Micrometer’s JettySslHandshakeMetrics.

@Timed Annotation Support

To use @Timed where it is not directly supported by Spring Boot, refer to the Micrometer documentation.

Redis Metrics

Auto-configuration registers a MicrometerCommandLatencyRecorder for the auto-configured LettuceConnectionFactory. For more detail, see the Micrometer Metrics section of the Lettuce documentation.