Allow dogstatsd port to be configurable with DD_DOGSTATSD_PORT (#8693)

* configurable dogstatsd port

Author: randomanderson

communication/src/main/java/datadog/communication/monitor/DDAgentStatsDClientManager.java

@@ -1,6 +1,5 @@
 package datadog.communication.monitor;
 
-import static datadog.trace.api.ConfigDefaults.DEFAULT_DOGSTATSD_PORT;
 import static datadog.trace.bootstrap.instrumentation.api.WriterConstants.LOGGING_WRITER_TYPE;
 
 import datadog.trace.api.Config;
@@ -22,7 +21,8 @@ public static StatsDClientManager statsDClientManager() {
     return INSTANCE;
   }
 
-  private static final AtomicInteger defaultStatsDPort = new AtomicInteger(DEFAULT_DOGSTATSD_PORT);
+  private static final AtomicInteger defaultStatsDPort =
+      new AtomicInteger(Config.get().getDogsStatsDPort());
 
   public static void setDefaultStatsDPort(final int newPort) {
     if (newPort > 0 && defaultStatsDPort.getAndSet(newPort) != newPort) {

internal-api/src/main/java/datadog/trace/api/Config.java

@@ -527,6 +527,7 @@ public static String getHostName() {
   private final List<String> traceAgentArgs;
   private final String dogStatsDPath;
   private final List<String> dogStatsDArgs;
+  private final int dogStatsDPort;
 
   private String env;
   private String version;
@@ -1084,6 +1085,8 @@ private Config(final ConfigProvider configProvider, final InstrumenterConfig ins
         configProvider.getInteger(
             DOGSTATSD_START_DELAY, DEFAULT_DOGSTATSD_START_DELAY, JMX_FETCH_START_DELAY);
 
+    dogStatsDPort = configProvider.getInteger(DOGSTATSD_PORT, DEFAULT_DOGSTATSD_PORT);
+
     statsDClientQueueSize = configProvider.getInteger(STATSD_CLIENT_QUEUE_SIZE);
     statsDClientSocketBuffer = configProvider.getInteger(STATSD_CLIENT_SOCKET_BUFFER);
     statsDClientSocketTimeout = configProvider.getInteger(STATSD_CLIENT_SOCKET_TIMEOUT);
@@ -3528,6 +3531,10 @@ public List<String> getDogStatsDArgs() {
     return dogStatsDArgs;
   }
 
+  public int getDogsStatsDPort() {
+    return dogStatsDPort;
+  }
+
   public String getConfigFileStatus() {
     return configFileStatus;
   }