Standardize a utility method for getting local host names.

service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java

@@ -193,6 +193,7 @@ import org.whispersystems.textsecuregcm.storage.UsernamesManager;
 import org.whispersystems.textsecuregcm.util.AsnManager;
 import org.whispersystems.textsecuregcm.util.Constants;
 import org.whispersystems.textsecuregcm.util.DynamoDbFromConfig;
+import org.whispersystems.textsecuregcm.util.HostnameUtil;
 import org.whispersystems.textsecuregcm.util.TorExitNodeManager;
 import org.whispersystems.textsecuregcm.websocket.AuthenticatedConnectListener;
 import org.whispersystems.textsecuregcm.websocket.DeadLetterHandler;
@@ -280,21 +281,6 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
     });
 
     {
-      final String hostname;
-
-      {
-        String localHostName = "unknown";
-
-        try {
-          localHostName = InetAddress.getLocalHost().getHostName().toLowerCase(Locale.US);
-          log.info("Setting host tag to {}", localHostName);
-        } catch (final UnknownHostException e) {
-          log.warn("Failed to get hostname", e);
-        }
-
-        hostname = localHostName;
-      }
-
       final DatadogMeterRegistry datadogMeterRegistry = new DatadogMeterRegistry(new DatadogConfig() {
         @Override
         public String get(final String key) {
@@ -320,7 +306,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
       datadogMeterRegistry.config().commonTags(
           Tags.of(
               "service", "chat",
-              "host", hostname,
+              "host", HostnameUtil.getLocalHostname(),
               "version", WhisperServerVersion.getServerVersion(),
               "env", config.getDatadogConfiguration().getEnvironment()))
           .meterFilter(MeterFilter.denyNameStartsWith(MetricsRequestEventListener.REQUEST_COUNTER_NAME))

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

@@ -21,6 +21,7 @@ import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.whispersystems.textsecuregcm.util.HostnameUtil;
 
 import javax.ws.rs.core.UriBuilder;
 import java.io.ByteArrayOutputStream;
@@ -83,7 +84,7 @@ public class JsonMetricsReporter extends ScheduledReporter {
   {
     super(registry, "json-reporter", filter, rateUnit, durationUnit, Executors.newSingleThreadScheduledExecutor(new NamedThreadFactory("json-reporter")), true, disabledMetricAttributes);
     this.httpClient = HttpClient.newBuilder().version(HttpClient.Version.HTTP_2).build();
-    this.uri        = UriBuilder.fromUri(uri).queryParam("h", InetAddress.getLocalHost().getHostName()).build();
+    this.uri        = UriBuilder.fromUri(uri).queryParam("h", HostnameUtil.getLocalHostname()).build();
   }
 
   @Override

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

@@ -27,6 +27,7 @@ import javax.validation.constraints.NotEmpty;
 import net.logstash.logback.appender.LogstashTcpSocketAppender;
 import net.logstash.logback.encoder.LogstashEncoder;
 import org.whispersystems.textsecuregcm.WhisperServerVersion;
+import org.whispersystems.textsecuregcm.util.HostnameUtil;
 
 @JsonTypeName("logstashtcpsocket")
 public class LogstashTcpSocketAppenderFactory extends AbstractAppenderFactory<ILoggingEvent> {
@@ -77,11 +78,7 @@ public class LogstashTcpSocketAppenderFactory extends AbstractAppenderFactory<IL
 
     final LogstashEncoder encoder = new LogstashEncoder();
     final ObjectNode customFieldsNode = new ObjectNode(JsonNodeFactory.instance);
-    try {
+    customFieldsNode.set("host", TextNode.valueOf(HostnameUtil.getLocalHostname()));
-      customFieldsNode.set("host", TextNode.valueOf(InetAddress.getLocalHost().getHostName()));
-    } catch (UnknownHostException e) {
-      customFieldsNode.set("host", TextNode.valueOf("unknown"));
-    }
     customFieldsNode.set("service", TextNode.valueOf("chat"));
     customFieldsNode.set("ddsource", TextNode.valueOf("logstash"));
     customFieldsNode.set("ddtags", TextNode.valueOf("env:" + environment + ",version:" + WhisperServerVersion.getServerVersion()));

service/src/main/java/org/whispersystems/textsecuregcm/util/HostnameUtil.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2013-2021 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Locale;
+
+public class HostnameUtil {
+
+  private static final Logger log = LoggerFactory.getLogger(HostnameUtil.class);
+
+  public static String getLocalHostname() {
+    try {
+      return InetAddress.getLocalHost().getHostName().toLowerCase(Locale.US);
+    } catch (final UnknownHostException e) {
+      log.warn("Failed to get hostname", e);
+      return "unknown";
+    }
+  }
+}