Revert "Add support for Reactor Netty Micrometer metrics"

This commit removes the support for Reactor Netty metrics since it
seems that Spring Boot should not use this feature:

* HTTP metrics are already covered by WebFlux
* TCP metrics are only meant to TCP server/clients
* allocator metrics are already provided by Netty and there is
no specific API to enable them here.

Closes gh-19388

Author: bclozel

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/WebClientMetricsConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@
 package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
 import io.micrometer.core.instrument.MeterRegistry;
-import reactor.netty.http.client.HttpClient;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties.Web.Client.ClientRequest;
@@ -26,7 +25,6 @@
 import org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTagsProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.autoconfigure.web.reactive.function.client.ReactorNettyHttpClientMapper;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.reactive.function.client.WebClient;
@@ -55,14 +53,4 @@ MetricsWebClientCustomizer metricsWebClientCustomizer(MeterRegistry meterRegistr
 				request.getAutotime());
 	}
 
-	@ConditionalOnClass(HttpClient.class)
-	static class ReactorNettyClientMetricsConfiguration {
-
-		@Bean
-		ReactorNettyHttpClientMapper metricsHttpClientMapper() {
-			return (httpClient) -> httpClient.tcpConfiguration((tcpClient) -> tcpClient.metrics(true));
-		}
-
-	}
-
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/netty/NettyMetricsAutoConfiguration.java

@@ -71,7 +71,6 @@ org.springframework.boot.actuate.autoconfigure.metrics.orm.jpa.HibernateMetricsA
 org.springframework.boot.actuate.autoconfigure.metrics.r2dbc.ConnectionPoolMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.jetty.JettyMetricsAutoConfiguration,\
-org.springframework.boot.actuate.autoconfigure.metrics.web.netty.NettyMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.reactive.WebFluxMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.servlet.WebMvcMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.tomcat.TomcatMetricsAutoConfiguration,\

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/netty/package-info.java

@@ -18,25 +18,16 @@
 
 import java.time.Duration;
 
-import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Metrics;
 import io.micrometer.core.instrument.Timer;
-import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import io.micrometer.core.instrument.distribution.HistogramSnapshot;
-import io.micrometer.core.instrument.simple.SimpleConfig;
-import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
-import okhttp3.mockwebserver.MockResponse;
-import okhttp3.mockwebserver.MockWebServer;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import reactor.core.publisher.Mono;
-import reactor.netty.http.client.HttpClient;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.test.MetricsRun;
 import org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTagsProvider;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
 import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
@@ -116,47 +107,6 @@ void autoTimeRequestsCanBeConfigured() {
 				});
 	}
 
-	@Test
-	void shouldConfigureMetricsForReactorNetty() {
-		this.contextRunner.withConfiguration(AutoConfigurations.of(ClientHttpConnectorAutoConfiguration.class))
-				.run((context) -> {
-					CompositeMeterRegistry registry = Metrics.globalRegistry;
-					MockWebServer server = new MockWebServer();
-					try {
-						server.start();
-						server.enqueue(new MockResponse());
-						String serverAddress = "http://" + server.getHostName() + ":" + server.getPort();
-						WebClient.Builder builder = context.getBean(WebClient.Builder.class);
-						WebClient client = builder.baseUrl(serverAddress).build();
-						assertThat(registry.find("reactor.netty.tcp.client.connect.time").timer()).isNull();
-						client.get().uri("/test").retrieve().toBodilessEntity().block();
-						assertThat(registry.find("reactor.netty.tcp.client.connect.time").timer()).isNotNull();
-					}
-					finally {
-						server.shutdown();
-					}
-				});
-	}
-
-	@Test
-	void sanityTest() throws Exception {
-		MockWebServer server = new MockWebServer();
-		try {
-			server.start();
-			server.enqueue(new MockResponse());
-			SimpleMeterRegistry registry = new SimpleMeterRegistry(SimpleConfig.DEFAULT, Clock.SYSTEM);
-			Metrics.addRegistry(registry);
-			HttpClient client = HttpClient.create().metrics(true);
-			assertThat(registry.find("reactor.netty.http.client.connect.time").timer()).isNull();
-			client.get().uri("http://" + server.getHostName() + ":" + server.getPort()).response().block();
-			assertThat(registry.find("reactor.netty.http.client.connect.time").timer()).isNotNull();
-		}
-		finally {
-			server.shutdown();
-		}
-
-	}
-
 	private MeterRegistry getInitializedMeterRegistry(AssertableApplicationContext context) {
 		WebClient webClient = mockWebClient(context.getBean(WebClient.Builder.class));
 		MeterRegistry registry = context.getBean(MeterRegistry.class);

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -1813,7 +1813,6 @@ Spring Boot registers the following core metrics when applicable:
 * Logback metrics: record the number of events logged to Logback at each level
 * Uptime metrics: report a gauge for uptime and a fixed gauge representing the application's absolute start time
 * Tomcat metrics (`server.tomcat.mbeanregistry.enabled` must be set to `true` for all Tomcat metrics to be registered)
-* Reactor Netty metrics (TCP and allocator metrics for client and server)
 * {spring-integration-docs}system-management.html#micrometer-integration[Spring Integration] metrics