Split up tag configurers for web monitoring, shuffle configurations f…

…or Boot 1.x support

build.gradle

@@ -106,6 +106,8 @@ jmh {
     duplicateClassesStrategy = 'warn'
 }
 
-bintray.pkg {
-    labels = ['spring', 'metrics', 'prometheus', 'spectator']
+if(project.extensions.findByName('bintray')) {
+    bintray.pkg {
+        labels = ['spring', 'metrics', 'prometheus', 'spectator']
+    }
 }

src/main/java/org/springframework/metrics/boot/EnableMetrics.java

@@ -15,7 +15,6 @@
  */
 package org.springframework.metrics.boot;
 
-import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 
 import java.lang.annotation.*;
@@ -27,12 +26,7 @@
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Import(MetricsBoot1Configuration.class)
+@Import({ MetricsConfiguration.class, MetricsBoot1Configuration.class })
 public @interface EnableMetrics {
 }
 
-@Configuration
-class MetricsConfiguration {
-    // TODO when we figure out if or how Boot 2 might be different, implement this
-    // https://github.com/spring-projects/spring-metrics/wiki/Enhancements-To-Spring-5.0-and-Boot-2.0
-}

src/main/java/org/springframework/metrics/boot/InstrumentRestTemplateConfiguration.java

@@ -0,0 +1,98 @@
+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ *
+ * 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.metrics.boot;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.Environment;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.metrics.instrument.MeterRegistry;
+import org.springframework.metrics.instrument.TagFormatter;
+import org.springframework.metrics.instrument.web.MetricsRestTemplateInterceptor;
+import org.springframework.metrics.instrument.web.RestTemplateTagConfigurer;
+import org.springframework.web.client.RestTemplate;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Configuration
+@ConditionalOnClass(RestTemplate.class)
+class InstrumentRestTemplateConfiguration {
+    @Autowired(required = false)
+    RestTemplateTagConfigurer tagConfigurer;
+
+    @Bean
+    @ConditionalOnMissingBean(RestTemplateTagConfigurer.class)
+    RestTemplateTagConfigurer restTemplateTagConfigurer(TagFormatter tagFormatter) {
+        if(tagConfigurer != null)
+            return tagConfigurer;
+        this.tagConfigurer = new RestTemplateTagConfigurer(tagFormatter);
+        return tagConfigurer;
+    }
+
+    @Bean
+    MetricsRestTemplateInterceptor clientHttpRequestInterceptor(MeterRegistry meterRegistry,
+                                                                TagFormatter tagFormatter,
+                                                                Environment environment) {
+        return new MetricsRestTemplateInterceptor(meterRegistry, restTemplateTagConfigurer(tagFormatter),
+                environment.getProperty("spring.metrics.web.client_requests.name", "http_client_requests"));
+    }
+
+    @Bean
+    static BeanPostProcessor restTemplateInterceptorPostProcessor() {
+        return new MetricsInterceptorPostProcessor();
+    }
+
+    private static class MetricsInterceptorPostProcessor
+            implements BeanPostProcessor, ApplicationContextAware {
+        private ApplicationContext context;
+        private MetricsRestTemplateInterceptor interceptor;
+
+        @Override
+        public Object postProcessBeforeInitialization(Object bean, String beanName) {
+            return bean;
+        }
+
+        @Override
+        public Object postProcessAfterInitialization(Object bean, String beanName) {
+            if (bean instanceof RestTemplate) {
+                if (this.interceptor == null) {
+                    this.interceptor = this.context
+                            .getBean(MetricsRestTemplateInterceptor.class);
+                }
+                RestTemplate restTemplate = (RestTemplate) bean;
+                // create a new list as the old one may be unmodifiable (ie Arrays.asList())
+                List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();
+                interceptors.add(interceptor);
+                interceptors.addAll(restTemplate.getInterceptors());
+                restTemplate.setInterceptors(interceptors);
+            }
+            return bean;
+        }
+
+        @Override
+        public void setApplicationContext(ApplicationContext context) throws BeansException {
+            this.context = context;
+        }
+    }
+}