Remove Servo dependency from core, move to submodule

hystrix-contrib/hystrix-servo-metrics-publisher/build.gradle

@@ -0,0 +1,5 @@
+    apply plugin: 'java'
+    dependencies {
+        compile project(':hystrix-core')
+        compile 'com.netflix.servo:servo-core:0.4.27'
+    }

hystrix-contrib/hystrix-servo-metrics-publisher/src/main/java/com/netflix/hystrix/contrib/servopublisher/HystrixServoMetricsPublisher.java

@@ -0,0 +1,56 @@
+/**
+ * Copyright 2012 Netflix, 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 com.netflix.hystrix.contrib.servopublisher;
+
+import com.netflix.hystrix.HystrixCircuitBreaker;
+import com.netflix.hystrix.HystrixCommandGroupKey;
+import com.netflix.hystrix.HystrixCommandKey;
+import com.netflix.hystrix.HystrixCommandMetrics;
+import com.netflix.hystrix.HystrixCommandProperties;
+import com.netflix.hystrix.HystrixThreadPoolKey;
+import com.netflix.hystrix.HystrixThreadPoolMetrics;
+import com.netflix.hystrix.HystrixThreadPoolProperties;
+import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher;
+import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisherCommand;
+import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisherThreadPool;
+
+/**
+ * Servo implementation of {@link HystrixMetricsPublisher}.
+ * <p>
+ * See <a href="https://github.com/Netflix/Hystrix/wiki/Plugins">Wiki docs</a> about plugins for more information.
+ */
+public class HystrixServoMetricsPublisher extends HystrixMetricsPublisher {
+
+    private static HystrixServoMetricsPublisher INSTANCE = new HystrixServoMetricsPublisher();
+
+    public static HystrixServoMetricsPublisher getInstance() {
+        return INSTANCE;
+    }
+
+    private HystrixServoMetricsPublisher() {
+    }
+
+    @Override
+    public HystrixMetricsPublisherCommand getMetricsPublisherForCommand(HystrixCommandKey commandKey, HystrixCommandGroupKey commandGroupKey, HystrixCommandMetrics metrics, HystrixCircuitBreaker circuitBreaker, HystrixCommandProperties properties) {
+        return new HystrixServoMetricsPublisherCommand(commandKey, commandGroupKey, metrics, circuitBreaker, properties);
+    }
+
+    @Override
+    public HystrixMetricsPublisherThreadPool getMetricsPublisherForThreadPool(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolMetrics metrics, HystrixThreadPoolProperties properties) {
+        return new HystrixServoMetricsPublisherThreadPool(threadPoolKey, metrics, properties);
+    }
+
+}

hystrix-core/src/main/java/com/netflix/hystrix/strategy/metrics/HystrixMetricsServoPublisherAbstract.java → hystrix-contrib/hystrix-servo-metrics-publisher/src/main/java/com/netflix/hystrix/contrib/servopublisher/HystrixServoMetricsPublisherAbstract.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.netflix.hystrix.strategy.metrics;
+package com.netflix.hystrix.contrib.servopublisher;
 
 import com.netflix.hystrix.HystrixCommandMetrics;
 import com.netflix.hystrix.util.HystrixRollingNumberEvent;
@@ -27,9 +27,9 @@
 import com.netflix.servo.tag.Tag;
 
 /**
- * Utility used for Servo (https://github.com/Netflix/servo) based default implementations of metrics publishers.
+ * Utility used for Servo (https://github.com/Netflix/servo) based implementations of metrics publishers.
  */
-/* package */abstract class HystrixMetricsServoPublisherAbstract {
+/* package */abstract class HystrixServoMetricsPublisherAbstract {
 
     protected abstract Tag getServoTypeTag();