Add elastic implementation

build.gradle

@@ -47,7 +47,7 @@ subprojects {
         }
 
         if (project.extensions.findByName('bintray')) {
-            bintray.labels = ['micrometer', 'atlas', 'metrics', 'prometheus', 'spectator', 'influx', 'new-relic', 'signalfx', 'wavefront']
+            bintray.labels = ['micrometer', 'atlas', 'metrics', 'prometheus', 'spectator', 'influx', 'new-relic', 'signalfx', 'wavefront', 'elastic']
         }
     }
 

implementations/micrometer-registry-elastic/build.gradle

@@ -0,0 +1,10 @@
+apply plugin: 'org.junit.platform.gradle.plugin'
+
+dependencies {
+    compile project(':micrometer-core')
+    compile 'com.fasterxml.jackson.core:jackson-core:latest.release'
+    compile 'com.fasterxml.jackson.core:jackson-databind:latest.release'
+    compile 'com.fasterxml.jackson.module:jackson-module-afterburner:latest.release'
+
+    testCompile project(':micrometer-test')
+}

implementations/micrometer-registry-elastic/src/main/java/io/micrometer/elastic/ElasticConfig.java

@@ -0,0 +1,157 @@
+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <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 io.micrometer.elastic;
+
+import io.micrometer.core.instrument.step.StepRegistryConfig;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @author Nicolas Portmann
+ */
+public interface ElasticConfig extends StepRegistryConfig {
+
+    /**
+     * Accept configuration defaults
+     */
+    ElasticConfig DEFAULT = k -> null;
+
+    /**
+     * Get the value associated with a key.
+     *
+     * @param key
+     *     Key to lookup in the config.
+     * @return
+     *     Value for the key or null if no key is present.
+     */
+    String get(String key);
+
+    /**
+     * Property prefix to prepend to configuration names.
+     */
+    default String prefix() {
+        return "elastic";
+    }
+
+    /**
+     * The hosts to send the metrics to
+     * Default is "http://localhost:9200"
+     */
+    default String[] hosts() {
+        String v = get(prefix() + ".hosts");
+        return v == null ? new String[]{"http://localhost:9200"} : v.split(",");
+    }
+
+    /**
+     * Prefix all metrics with a given {@link String}.
+     * Default is ""
+     */
+    default String metricPrefix() {
+        String v = get(prefix() + ".metricPrefix");
+        return v == null ? "" : v;
+    }
+
+    /**
+     * Convert all durations to a certain {@link TimeUnit}
+     * Default is {@link TimeUnit#SECONDS}
+     */
+    default TimeUnit rateUnits() {
+        String v = get(prefix() + ".rateUnits");
+        return v == null ? TimeUnit.SECONDS : TimeUnit.valueOf(v.toUpperCase());
+    }
+
+    /**
+     * Convert all durations to a certain {@link TimeUnit}
+     * Default is {@link TimeUnit#MILLISECONDS}
+     */
+    default TimeUnit durationUnits() {
+        String v = get(prefix() + ".durationUnits");
+        return v == null ? TimeUnit.MILLISECONDS : TimeUnit.valueOf(v.toUpperCase());
+    }
+
+    /**
+     * The timeout to wait for until a connection attempt is and the next host is tried.
+     * Default is: 1000
+     */
+    default int timeout() {
+        String v = get(prefix() + ".timeout");
+        return v == null ? 1000 : Integer.parseInt(v);
+    }
+
+    /**
+     * The index name to write metrics to.
+     * Default is: "metrics"
+     */
+    default String index() {
+        String v = get(prefix() + ".index");
+        return v == null ? "metrics" : v;
+    }
+
+    /**
+     * The index date format used for rolling indices.
+     * This is appended to the index name, split by a '-'.
+     * Default is: "yyyy-MM"
+     */
+    default String indexDateFormat() {
+        String v = get(prefix() + ".indexDateFormat");
+        return v == null ? "yyyy-MM" : v;
+    }
+
+    /**
+     * The bulk size per request.
+     * Default is: 2500
+     */
+    default int bulkSize() {
+        String v = get(prefix() + ".bulkSize");
+        return v == null ? 2500 : Integer.parseInt(v);
+    }
+
+    /**
+     * The name of the timestamp field.
+     * Default is: "@timestamp"
+     */
+    default String timeStampFieldName() {
+        String v = get(prefix() + ".timeStampFieldName");
+        return v == null ? "@timestamp" : v;
+    }
+
+    /**
+     * Whether to create the index automatically if it doesn't exist.
+     * Default is: {@code true}
+     */
+    default boolean autoCreateIndex() {
+        String v = get(prefix() + ".autoCreateIndex");
+        return v == null || Boolean.valueOf(v);
+    }
+
+    /**
+     * The Basic Authentication username.
+     * Default is: "" (= do not perform Basic Authentication)
+     */
+    default String userName() {
+        String v = get(prefix() + ".userName");
+        return v == null ? "" : v;
+    }
+
+    /**
+     * The Basic Authentication password.
+     * Default is: "" (= do not perform Basic Authentication)
+     */
+    default String password() {
+        String v = get(prefix() + ".password");
+        return v == null ? "" : v;
+    }
+}