Add support for api gateway metrics

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -21,6 +21,8 @@ import java.util.List;
 import java.util.function.Consumer;
 
 import com.netflix.hystrix.HystrixObservableCommand;
+
+import io.micrometer.core.instrument.MeterRegistry;
 import io.netty.channel.ChannelOption;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 import reactor.core.publisher.Flux;
@@ -48,6 +50,7 @@ import org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter;
 import org.springframework.cloud.gateway.filter.ForwardPathFilter;
 import org.springframework.cloud.gateway.filter.ForwardRoutingFilter;
 import org.springframework.cloud.gateway.filter.GlobalFilter;
+import org.springframework.cloud.gateway.filter.GatewayMetricsFilter;
 import org.springframework.cloud.gateway.filter.NettyRoutingFilter;
 import org.springframework.cloud.gateway.filter.NettyWriteResponseFilter;
 import org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter;
@@ -320,6 +323,12 @@ public class GatewayAutoConfiguration {
 
 
 	// GlobalFilter beans
+	
+	@Bean
+	@ConditionalOnProperty(name = "spring.cloud.gateway.metrics.enabled", matchIfMissing = true)	
+	public GatewayMetricsFilter gatewayMetricFilter(MeterRegistry meterRegistry) {
+		return new GatewayMetricsFilter(meterRegistry);
+	}
 
 	@Bean
 	public AdaptCachedBodyGlobalFilter adaptCachedBodyGlobalFilter() {

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/GatewayMetricsFilter.java

@@ -0,0 +1,47 @@
+package org.springframework.cloud.gateway.filter;
+
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR;
+
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+
+import org.springframework.cloud.gateway.route.Route;
+import org.springframework.core.Ordered;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.server.ServerWebExchange;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
+import reactor.core.publisher.Mono;
+
+public class GatewayMetricsFilter implements GlobalFilter, Ordered {
+
+	private MeterRegistry meterRegistry;
+
+	public GatewayMetricsFilter(MeterRegistry meterRegistry) {
+		this.meterRegistry = meterRegistry;
+	}
+
+	@Override
+	public int getOrder() {
+		return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER - 1;
+	}
+
+	@Override
+	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
+		long start = System.nanoTime();
+		return chain.filter(exchange).then(Mono.defer(() -> {
+			HttpStatus statusCode = exchange.getResponse().getStatusCode();
+			boolean success = statusCode.is2xxSuccessful();
+			Route route = exchange.getAttribute(GATEWAY_ROUTE_ATTR);
+			Iterable<Tag> iterableTags = Arrays.asList(
+					Tag.of("success", Boolean.toString(success)),
+					Tag.of("httpStatus", statusCode.name()),
+					Tag.of("routeId", route.getId()),
+					Tag.of("routeUri", route.getUri().toString()));
+			meterRegistry.timer("gateway.requests", iterableTags)
+					.record(System.nanoTime() - start, TimeUnit.NANOSECONDS);
+			return Mono.empty();
+		}));
+	}
+}

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/config/GatewayAutoConfigurationTests.java

@@ -24,6 +24,8 @@ import reactor.ipc.netty.http.client.HttpClientOptions;
 import reactor.ipc.netty.options.ClientProxyOptions;
 import reactor.ipc.netty.resources.PoolResources;
 
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration;
 import org.springframework.boot.test.context.runner.ReactiveWebApplicationContextRunner;
@@ -36,6 +38,8 @@ public class GatewayAutoConfigurationTests {
 	public void nettyHttpClientDefaults() {
 		new ReactiveWebApplicationContextRunner()
 				.withConfiguration(AutoConfigurations.of(WebFluxAutoConfiguration.class,
+						MetricsAutoConfiguration.class,
+						SimpleMetricsExportAutoConfiguration.class,
 						GatewayAutoConfiguration.class))
 				.withPropertyValues("debug=true")
 				.run(context -> {
@@ -59,6 +63,8 @@ public class GatewayAutoConfigurationTests {
 	public void nettyHttpClientConfigured() {
 		new ReactiveWebApplicationContextRunner()
 				.withConfiguration(AutoConfigurations.of(WebFluxAutoConfiguration.class,
+						MetricsAutoConfiguration.class,
+						SimpleMetricsExportAutoConfiguration.class,
 						GatewayAutoConfiguration.class))
 				.withPropertyValues("spring.cloud.gateway.httpclient.ssl.use-insecure-trust-manager=true",
 						"spring.cloud.gateway.httpclient.connect-timeout=10",

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/GatewayMetricFilterTests.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2013-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.springframework.cloud.gateway.filter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.gateway.config.GatewayProperties;
+import org.springframework.cloud.gateway.test.BaseWebClientTests;
+import org.springframework.context.annotation.Import;
+import org.springframework.http.HttpStatus;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import io.micrometer.core.instrument.MeterRegistry;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = RANDOM_PORT)
+@DirtiesContext
+public class GatewayMetricFilterTests extends BaseWebClientTests {
+
+	private static final String REQUEST_METRICS_NAME = "gateway.requests";
+	
+	@Autowired
+	private GatewayProperties properties;
+
+	@Autowired
+	private MeterRegistry meterRegistry;
+
+	@Test
+	public void gatewayRequestsMeterFilterHasTags() {
+		assertThat(this.properties.getDefaultFilters()).isNotEmpty();
+
+		testClient.get().uri("/headers").exchange().expectStatus().isOk();
+		assertMetricsContainsTag("success", Boolean.TRUE.toString());
+		assertMetricsContainsTag("httpStatus", HttpStatus.OK.name());
+		assertMetricsContainsTag("routeId", "default_path_to_httpbin");
+		assertMetricsContainsTag("routeUri", "lb://testservice");
+	}
+
+	private void assertMetricsContainsTag(String tagKey, String tagValue) {
+		assertThat(this.meterRegistry.get(REQUEST_METRICS_NAME).tag(tagKey, tagValue).timer()
+				.count()).isEqualTo(1);
+	}
+
+	@EnableAutoConfiguration
+	@SpringBootConfiguration
+	@Import(DefaultTestConfig.class)
+	public static class TestConfig {
+
+	}
+
+}