Add the host tag to datadog metric reporting

service/src/main/java/org/whispersystems/textsecuregcm/metrics/SignalDatadogReporterFactory.java

@@ -0,0 +1,63 @@
+package org.whispersystems.textsecuregcm.metrics;
+
+import com.amazonaws.util.EC2MetadataUtils;
+import com.codahale.metrics.MetricRegistry;
+import com.codahale.metrics.ScheduledReporter;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import io.dropwizard.metrics.BaseReporterFactory;
+import org.coursera.metrics.datadog.DatadogReporter;
+import org.coursera.metrics.datadog.DefaultMetricNameFormatterFactory;
+import org.coursera.metrics.datadog.DynamicTagsCallbackFactory;
+import org.coursera.metrics.datadog.MetricNameFormatterFactory;
+import org.coursera.metrics.datadog.transport.AbstractTransportFactory;
+
+import javax.validation.Valid;
+import javax.validation.constraints.NotNull;
+import java.util.EnumSet;
+import java.util.List;
+
+@SuppressWarnings("FieldMayBeFinal")
+@JsonTypeName("signaldatadog")
+public class SignalDatadogReporterFactory extends BaseReporterFactory {
+
+  @JsonProperty
+  private List<String> tags = null;
+
+  @Valid
+  @JsonProperty
+  private DynamicTagsCallbackFactory dynamicTagsCallback = null;
+
+  @JsonProperty
+  private String prefix = null;
+
+  @Valid
+  @NotNull
+  @JsonProperty
+  private EnumSet<DatadogReporter.Expansion> expansions = DatadogReporter.Expansion.ALL;
+
+  @Valid
+  @NotNull
+  @JsonProperty
+  private MetricNameFormatterFactory metricNameFormatter = new DefaultMetricNameFormatterFactory();
+
+  @Valid
+  @NotNull
+  @JsonProperty
+  private AbstractTransportFactory transport = null;
+
+  public ScheduledReporter build(MetricRegistry registry) {
+    return DatadogReporter.forRegistry(registry)
+                          .withTransport(transport.build())
+                          .withHost(EC2MetadataUtils.getInstanceId())
+                          .withTags(tags)
+                          .withPrefix(prefix)
+                          .withExpansions(expansions)
+                          .withMetricNameFormatter(metricNameFormatter.build())
+                          .withDynamicTagCallback(dynamicTagsCallback != null ? dynamicTagsCallback.build() : null)
+                          .filter(getFilter())
+                          .convertDurationsTo(getDurationUnit())
+                          .convertRatesTo(getRateUnit())
+                          .build();
+  }
+}