Support metric names customization (#1311)

Co-authored-by: Kevin Davis <kdavisk6@gmail.com>

Author: Kuvaldis

micrometer/src/main/java/feign/micrometer/FeignMetricName.java

@@ -24,28 +24,32 @@
 import java.util.Arrays;
 import java.util.List;
 
-public final class FeignMetricName {
+public final class FeignMetricName implements MetricName {
 
   private final Class<?> meteredComponent;
 
   public FeignMetricName(Class<?> meteredComponent) {
     this.meteredComponent = meteredComponent;
   }
 
+  @Override
   public String name(String suffix) {
     return name()
         // any separator, so naming convention can change it
         + "." + suffix;
   }
 
+  @Override
   public String name() {
     return meteredComponent.getName();
   }
 
+  @Override
   public Tags tag(MethodMetadata methodMetadata, Target<?> target, Tag... tags) {
     return tag(methodMetadata.targetType(), methodMetadata.method(), target.url(), tags);
   }
 
+  @Override
   public Tags tag(Class<?> targetType, Method method, String url, Tag... extraTags) {
     List<Tag> tags = new ArrayList<>();
     tags.add(Tag.of("client", targetType.getName()));

micrometer/src/main/java/feign/micrometer/MeteredClient.java

@@ -26,12 +26,16 @@ public class MeteredClient implements Client {
 
   private final Client client;
   private final MeterRegistry meterRegistry;
-  private final FeignMetricName metricName;
+  private final MetricName metricName;
 
   public MeteredClient(Client client, MeterRegistry meterRegistry) {
+    this(client, meterRegistry, new FeignMetricName(Client.class));
+  }
+
+  public MeteredClient(Client client, MeterRegistry meterRegistry, MetricName metricName) {
     this.client = client;
     this.meterRegistry = meterRegistry;
-    this.metricName = new FeignMetricName(Client.class);
+    this.metricName = metricName;
   }
 
   @Override

micrometer/src/main/java/feign/micrometer/MeteredDecoder.java

@@ -29,12 +29,16 @@ public class MeteredDecoder implements Decoder {
 
   private final Decoder decoder;
   private final MeterRegistry meterRegistry;
-  private final FeignMetricName metricName;
+  private final MetricName metricName;
 
   public MeteredDecoder(Decoder decoder, MeterRegistry meterRegistry) {
+    this(decoder, meterRegistry, new FeignMetricName(Decoder.class));
+  }
+
+  public MeteredDecoder(Decoder decoder, MeterRegistry meterRegistry, MetricName metricName) {
     this.decoder = decoder;
     this.meterRegistry = meterRegistry;
-    this.metricName = new FeignMetricName(Decoder.class);
+    this.metricName = metricName;
   }
 
   @Override

micrometer/src/main/java/feign/micrometer/MeteredEncoder.java

@@ -24,12 +24,16 @@ public class MeteredEncoder implements Encoder {
 
   private final Encoder encoder;
   private final MeterRegistry meterRegistry;
-  private final FeignMetricName metricName;
+  private final MetricName metricName;
 
   public MeteredEncoder(Encoder encoder, MeterRegistry meterRegistry) {
+    this(encoder, meterRegistry, new FeignMetricName(Encoder.class));
+  }
+
+  public MeteredEncoder(Encoder encoder, MeterRegistry meterRegistry, MetricName metricName) {
     this.encoder = encoder;
     this.meterRegistry = meterRegistry;
-    this.metricName = new FeignMetricName(Encoder.class);
+    this.metricName = metricName;
   }
 
   @Override

micrometer/src/main/java/feign/micrometer/MeteredInvocationHandleFactory.java

@@ -40,13 +40,20 @@ public class MeteredInvocationHandleFactory implements InvocationHandlerFactory
 
   private final MeterRegistry meterRegistry;
 
-  private final FeignMetricName metricName;
+  private final MetricName metricName;
 
   public MeteredInvocationHandleFactory(
       InvocationHandlerFactory invocationHandler, MeterRegistry meterRegistry) {
+    this(invocationHandler, meterRegistry, new FeignMetricName(Feign.class));
+  }
+
+  public MeteredInvocationHandleFactory(
+      InvocationHandlerFactory invocationHandler,
+      MeterRegistry meterRegistry,
+      MetricName metricName) {
     this.invocationHandler = invocationHandler;
     this.meterRegistry = meterRegistry;
-    this.metricName = new FeignMetricName(Feign.class);
+    this.metricName = metricName;
   }
 
   @Override

micrometer/src/main/java/feign/micrometer/MetricName.java

@@ -0,0 +1,31 @@
+/**
+ * Copyright 2012-2020 The Feign Authors
+ *
+ * <p>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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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 feign.micrometer;
+
+import feign.MethodMetadata;
+import feign.Target;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.Tags;
+import java.lang.reflect.Method;
+
+public interface MetricName {
+
+  String name();
+
+  String name(String suffix);
+
+  Tags tag(MethodMetadata methodMetadata, Target<?> target, Tag... tags);
+
+  Tags tag(Class<?> targetType, Method method, String url, Tag... extraTags);
+}