Add process tags to agent statsd client (#9904)

* Add process tags to agent statsd client

* close stuff in test

Author: amarziali

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

@@ -3,10 +3,12 @@
 import static datadog.trace.bootstrap.instrumentation.api.WriterConstants.LOGGING_WRITER_TYPE;
 
 import datadog.trace.api.Config;
+import datadog.trace.api.ProcessTags;
 import datadog.trace.api.StatsDClient;
 import datadog.trace.api.StatsDClientManager;
 import datadog.trace.api.cache.DDCache;
 import datadog.trace.api.cache.DDCaches;
+import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
@@ -52,8 +54,30 @@ public StatsDClient statsDClient(
       nameMapping = new NameResolver(namespace);
     }
 
-    if (null != constantTags && constantTags.length > 0) {
-      tagMapping = new TagCombiner(constantTags);
+    final List<String> processTags = ProcessTags.getTagsAsStringList();
+    final int processTagSize = processTags != null ? processTags.size() : 0;
+    String[] finalConstantTags = constantTags;
+    if (processTagSize > 0) {
+      final int constantTagSize = constantTags != null ? constantTags.length : 0;
+      if (constantTagSize == 0) {
+        finalConstantTags = processTags.toArray(new String[0]);
+      } else {
+        final int tagSizeSum = processTagSize + constantTagSize;
+        finalConstantTags = new String[tagSizeSum];
+        int pos = 0;
+        // copy constant tags
+        for (; pos < constantTagSize; pos++) {
+          finalConstantTags[pos] = constantTags[pos];
+        }
+        // copy process tags
+        for (int i = 0; i < processTagSize; i++) {
+          finalConstantTags[pos + i] = processTags.get(i);
+        }
+      }
+    }
+
+    if (null != finalConstantTags && finalConstantTags.length > 0) {
+      tagMapping = new TagCombiner(finalConstantTags);
     }
 
     if (USE_LOGGING_CLIENT) {

communication/src/test/groovy/datadog/communication/monitor/DDAgentStatsDClientTest.groovy

@@ -1,6 +1,8 @@
 package datadog.communication.monitor
 
+import static datadog.trace.api.config.GeneralConfig.EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED
 
+import datadog.trace.api.ProcessTags
 import datadog.trace.test.util.DDSpecification
 
 import static datadog.trace.api.config.GeneralConfig.DOGSTATSD_START_DELAY
@@ -109,13 +111,44 @@ class DDAgentStatsDClientTest extends DDSpecification {
     where:
     // spotless:off
     namespace | constantTags                        | expectedMetricName    | expectedCheckName    | expectedTags
-    null      | null                                | "test.metric"         | "test.check"         | "jmx_domain:java.nio,type:BufferPool"
-    null      | ["lang:java", "lang_version:1.8.0"] | "test.metric"         | "test.check"         | "jmx_domain:java.nio,type:BufferPool,lang:java,lang_version:1.8.0"
-    "example" | null                                | "example.test.metric" | "example.test.check" | "jmx_domain:java.nio,type:BufferPool"
-    "example" | ["lang:java", "lang_version:1.8.0"] | "example.test.metric" | "example.test.check" | "jmx_domain:java.nio,type:BufferPool,lang:java,lang_version:1.8.0"
+    null      | null                                | "test.metric"         | "test.check"         | "jmx_domain:java.nio,type:BufferPool,${ProcessTags.getTagsForSerialization().toString()}"
+    null      | ["lang:java", "lang_version:1.8.0"] | "test.metric"         | "test.check"         | "jmx_domain:java.nio,type:BufferPool,lang:java,lang_version:1.8.0,${ProcessTags.getTagsForSerialization().toString()}"
+    "example" | null                                | "example.test.metric" | "example.test.check" | "jmx_domain:java.nio,type:BufferPool,${ProcessTags.getTagsForSerialization().toString()}"
+    "example" | ["lang:java", "lang_version:1.8.0"] | "example.test.metric" | "example.test.check" | "jmx_domain:java.nio,type:BufferPool,lang:java,lang_version:1.8.0,${ProcessTags.getTagsForSerialization().toString()}"
     // spotless:on
   }
 
+  def "single statsd client without process tags"() {
+    setup:
+    injectSysConfig(DOGSTATSD_START_DELAY, '0')
+    injectSysConfig(EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED, "false")
+    def server = new StatsDServer()
+    server.start()
+    ProcessTags.reset()
+
+    def client = statsDClientManager().statsDClient('127.0.0.1', server.socket.localPort, null, namespace, constantTags as String[], false)
+
+    String metricName = "test.metric"
+    String[] tags = ["test:true"]
+
+    when:
+    client.incrementCounter(metricName, tags)
+
+    then:
+    server.waitForMessage().startsWith("$expectedMetricName:1|c|#$expectedTags")
+
+    cleanup:
+    injectSysConfig(EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED, "true")
+    ProcessTags.reset()
+    client.close()
+    server.close()
+
+    where:
+    namespace | constantTags                        | expectedMetricName    | expectedTags
+    null      | null                                | "test.metric"         | "test:true"
+    null      | ["lang:java", "lang_version:1.8.0"] | "test.metric"         | "test:true,lang:java,lang_version:1.8.0"
+  }
+
   def "single statsd client with event"() {
     setup:
     injectSysConfig(DOGSTATSD_START_DELAY, '0')