Support all value for DD_TRACE_EXPERIMENTAL_FEATURES_ENABLED (#8598)

Author: mhlidd

Diff for: dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java

@@ -236,7 +236,8 @@ public final class ConfigDefaults {
   static final boolean DEFAULT_TELEMETRY_LOG_COLLECTION_ENABLED = true;
   static final int DEFAULT_TELEMETRY_DEPENDENCY_RESOLUTION_QUEUE_SIZE = 100000;
 
-  static final Set<String> DEFAULT_TRACE_EXPERIMENTAL_FEATURES_ENABLED = new HashSet<>();
+  static final Set<String> DEFAULT_TRACE_EXPERIMENTAL_FEATURES_ENABLED =
+      new HashSet<>(asList("DD_TAGS", "DD_LOGS_INJECTION"));
 
   static final boolean DEFAULT_TRACE_128_BIT_TRACEID_GENERATION_ENABLED = true;
   static final boolean DEFAULT_TRACE_128_BIT_TRACEID_LOGGING_ENABLED = true;

Diff for: internal-api/src/main/java/datadog/trace/api/Config.java

@@ -633,8 +633,9 @@ private Config(final ConfigProvider configProvider, final InstrumenterConfig ins
             SERVLET_ROOT_CONTEXT_SERVICE_NAME, DEFAULT_SERVLET_ROOT_CONTEXT_SERVICE_NAME);
 
     experimentalFeaturesEnabled =
-        configProvider.getSet(
-            TRACE_EXPERIMENTAL_FEATURES_ENABLED, DEFAULT_TRACE_EXPERIMENTAL_FEATURES_ENABLED);
+        configProvider.getString(TRACE_EXPERIMENTAL_FEATURES_ENABLED, "").equals("all")
+            ? DEFAULT_TRACE_EXPERIMENTAL_FEATURES_ENABLED
+            : configProvider.getSet(TRACE_EXPERIMENTAL_FEATURES_ENABLED, new HashSet<>());
 
     integrationSynapseLegacyOperationName =
         configProvider.getBoolean(INTEGRATION_SYNAPSE_LEGACY_OPERATION_NAME, false);

Diff for: internal-api/src/test/groovy/datadog/trace/api/ConfigTest.groovy

@@ -637,6 +637,7 @@ class ConfigTest extends DDSpecification {
     System.setProperty(PREFIX + PROPAGATION_STYLE_INJECT, " ")
     System.setProperty(PREFIX + TRACE_LONG_RUNNING_ENABLED, "invalid")
     System.setProperty(PREFIX + TRACE_LONG_RUNNING_FLUSH_INTERVAL, "invalid")
+    System.setProperty(PREFIX + TRACE_EXPERIMENTAL_FEATURES_ENABLED, " ")
 
     when:
     def config = new Config()
@@ -666,6 +667,7 @@ class ConfigTest extends DDSpecification {
     config.tracePropagationStylesToExtract.toList() == [DATADOG, TRACECONTEXT, BAGGAGE]
     config.tracePropagationStylesToInject.toList() == [DATADOG, TRACECONTEXT, BAGGAGE]
     config.longRunningTraceEnabled == false
+    config.experimentalFeaturesEnabled == [].toSet()
   }
 
   def "sys props and env vars overrides for trace_agent_port and agent_port_legacy as expected"() {
@@ -1928,6 +1930,17 @@ class ConfigTest extends DDSpecification {
     config.globalTags == [env:"test", aKey:"aVal", bKey:"bVal"]
   }
 
+  def "verify behavior of DD_TRACE_EXPERIMENTAL_FEATURE_ENABLED when value is 'all'"() {
+    setup:
+    environmentVariables.set("DD_TRACE_EXPERIMENTAL_FEATURES_ENABLED", "all")
+
+    when:
+    def config = new Config()
+
+    then:
+    config.experimentalFeaturesEnabled == ["DD_TAGS", "DD_LOGS_INJECTION"].toSet()
+  }
+
   def "detect if agent is configured using default values"() {
     setup:
     if (host != null) {