Add agentless Feature Flagging configuration source

dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java

@@ -49,6 +49,12 @@ public final class ConfigDefaults {
   static final boolean DEFAULT_INJECT_DATADOG_ATTRIBUTE = true;
   static final String DEFAULT_SITE = "datadoghq.com";
 
+  public static final String DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE = "agentless";
+  public static final double DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_POLL_INTERVAL_SECONDS =
+      30.0D;
+  public static final double DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_REQUEST_TIMEOUT_SECONDS =
+      2.0D;
+
   static final boolean DEFAULT_CODE_ORIGIN_FOR_SPANS_INTERFACE_SUPPORT = false;
   static final int DEFAULT_CODE_ORIGIN_MAX_USER_FRAMES = 8;
   static final boolean DEFAULT_TRACE_ENABLED = true;

dd-trace-api/src/main/java/datadog/trace/api/config/FeatureFlaggingConfig.java

@@ -3,4 +3,13 @@
 public class FeatureFlaggingConfig {
 
   public static final String FLAGGING_PROVIDER_ENABLED = "experimental.flagging.provider.enabled";
+
+  public static final String FEATURE_FLAGS_CONFIGURATION_SOURCE =
+      "feature.flags.configuration.source";
+  public static final String FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_POLL_INTERVAL_SECONDS =
+      "feature.flags.configuration.source.agentless.poll.interval.seconds";
+  public static final String FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_REQUEST_TIMEOUT_SECONDS =
+      "feature.flags.configuration.source.agentless.request.timeout.seconds";
+
+  private FeatureFlaggingConfig() {}
 }

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

@@ -86,6 +86,9 @@
 import static datadog.trace.api.ConfigDefaults.DEFAULT_ELASTICSEARCH_BODY_ENABLED;
 import static datadog.trace.api.ConfigDefaults.DEFAULT_ELASTICSEARCH_PARAMS_ENABLED;
 import static datadog.trace.api.ConfigDefaults.DEFAULT_EXPERIMENTATAL_JEE_SPLIT_BY_DEPLOYMENT;
+import static datadog.trace.api.ConfigDefaults.DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE;
+import static datadog.trace.api.ConfigDefaults.DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_POLL_INTERVAL_SECONDS;
+import static datadog.trace.api.ConfigDefaults.DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_REQUEST_TIMEOUT_SECONDS;
 import static datadog.trace.api.ConfigDefaults.DEFAULT_GRPC_CLIENT_ERROR_STATUSES;
 import static datadog.trace.api.ConfigDefaults.DEFAULT_GRPC_SERVER_ERROR_STATUSES;
 import static datadog.trace.api.ConfigDefaults.DEFAULT_HEALTH_METRICS_ENABLED;
@@ -361,6 +364,9 @@
 import static datadog.trace.api.config.DebuggerConfig.THIRD_PARTY_EXCLUDES;
 import static datadog.trace.api.config.DebuggerConfig.THIRD_PARTY_INCLUDES;
 import static datadog.trace.api.config.DebuggerConfig.THIRD_PARTY_SHADING_IDENTIFIERS;
+import static datadog.trace.api.config.FeatureFlaggingConfig.FEATURE_FLAGS_CONFIGURATION_SOURCE;
+import static datadog.trace.api.config.FeatureFlaggingConfig.FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_POLL_INTERVAL_SECONDS;
+import static datadog.trace.api.config.FeatureFlaggingConfig.FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_REQUEST_TIMEOUT_SECONDS;
 import static datadog.trace.api.config.GeneralConfig.AGENTLESS_LOG_SUBMISSION_LEVEL;
 import static datadog.trace.api.config.GeneralConfig.AGENTLESS_LOG_SUBMISSION_QUEUE_SIZE;
 import static datadog.trace.api.config.GeneralConfig.AGENTLESS_LOG_SUBMISSION_URL;
@@ -1213,6 +1219,10 @@ public static String getHostName() {
 
   private final int remoteConfigMaxExtraServices;
 
+  private final String featureFlaggingConfigurationSource;
+  private final double featureFlaggingConfigurationSourcePollIntervalSeconds;
+  private final double featureFlaggingConfigurationSourceRequestTimeoutSeconds;
+
   private final boolean dbmInjectSqlBaseHash;
   private final String dbmPropagationMode;
   private final boolean dbmTracePreparedStatements;
@@ -2835,6 +2845,19 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
         configProvider.getInteger(
             REMOTE_CONFIG_MAX_EXTRA_SERVICES, DEFAULT_REMOTE_CONFIG_MAX_EXTRA_SERVICES);
 
+    featureFlaggingConfigurationSource =
+        normalizeFeatureFlaggingConfigurationSource(
+            configProvider.getString(
+                FEATURE_FLAGS_CONFIGURATION_SOURCE, DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE));
+    featureFlaggingConfigurationSourcePollIntervalSeconds =
+        configProvider.getDouble(
+            FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_POLL_INTERVAL_SECONDS,
+            DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_POLL_INTERVAL_SECONDS);
+    featureFlaggingConfigurationSourceRequestTimeoutSeconds =
+        configProvider.getDouble(
+            FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_REQUEST_TIMEOUT_SECONDS,
+            DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE_REQUEST_TIMEOUT_SECONDS);
+
     dynamicInstrumentationEnabled =
         configProvider.getBoolean(
             DYNAMIC_INSTRUMENTATION_ENABLED, DEFAULT_DYNAMIC_INSTRUMENTATION_ENABLED);
@@ -3747,6 +3770,14 @@ public boolean isInferredProxyPropagationEnabled() {
     return traceInferredProxyEnabled;
   }
 
+  private static String normalizeFeatureFlaggingConfigurationSource(final String source) {
+    if (source == null) {
+      return DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE;
+    }
+    final String normalized = source.trim().toLowerCase(Locale.ROOT);
+    return normalized.isEmpty() ? DEFAULT_FEATURE_FLAGGING_CONFIGURATION_SOURCE : normalized;
+  }
+
   public boolean isBaggageExtract() {
     return tracePropagationStylesToExtract.contains(TracePropagationStyle.BAGGAGE);
   }
@@ -4654,6 +4685,18 @@ public int getRemoteConfigMaxExtraServices() {
     return remoteConfigMaxExtraServices;
   }
 
+  public String getFeatureFlaggingConfigurationSource() {
+    return featureFlaggingConfigurationSource;
+  }
+
+  public double getFeatureFlaggingConfigurationSourcePollIntervalSeconds() {
+    return featureFlaggingConfigurationSourcePollIntervalSeconds;
+  }
+
+  public double getFeatureFlaggingConfigurationSourceRequestTimeoutSeconds() {
+    return featureFlaggingConfigurationSourceRequestTimeoutSeconds;
+  }
+
   public boolean isDynamicInstrumentationEnabled() {
     return dynamicInstrumentationEnabled;
   }
@@ -6486,6 +6529,12 @@ public String toString() {
         + remoteConfigMaxPayloadSize
         + ", remoteConfigIntegrityCheckEnabled="
         + remoteConfigIntegrityCheckEnabled
+        + ", featureFlaggingConfigurationSource="
+        + featureFlaggingConfigurationSource
+        + ", featureFlaggingConfigurationSourcePollIntervalSeconds="
+        + featureFlaggingConfigurationSourcePollIntervalSeconds
+        + ", featureFlaggingConfigurationSourceRequestTimeoutSeconds="
+        + featureFlaggingConfigurationSourceRequestTimeoutSeconds
         + ", debuggerEnabled="
         + dynamicInstrumentationEnabled
         + ", debuggerUploadTimeout="

metadata/supported-configurations.json

@@ -1497,6 +1497,30 @@
         "aliases": []
       }
     ],
+    "DD_FEATURE_FLAGS_CONFIGURATION_SOURCE": [
+      {
+        "version": "A",
+        "type": "string",
+        "default": "agentless",
+        "aliases": []
+      }
+    ],
+    "DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_POLL_INTERVAL_SECONDS": [
+      {
+        "version": "A",
+        "type": "decimal",
+        "default": "30",
+        "aliases": []
+      }
+    ],
+    "DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_REQUEST_TIMEOUT_SECONDS": [
+      {
+        "version": "A",
+        "type": "decimal",
+        "default": "2",
+        "aliases": []
+      }
+    ],
     "DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED": [
       {
         "version": "A",

products/feature-flagging/feature-flagging-agent/src/main/java/com/datadog/featureflag/FeatureFlaggingSystem.java

@@ -9,27 +9,50 @@ public class FeatureFlaggingSystem {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(FeatureFlaggingSystem.class);
 
-  private static volatile RemoteConfigService CONFIG_SERVICE;
+  private static volatile ConfigurationSourceService CONFIG_SERVICE;
   private static volatile ExposureWriter EXPOSURE_WRITER;
 
   private FeatureFlaggingSystem() {}
 
   public static void start(final SharedCommunicationObjects sco) {
     LOGGER.debug("Feature Flagging system starting");
     final Config config = Config.get();
+    CONFIG_SERVICE = createConfigurationSourceService(sco, config);
 
-    if (!config.isRemoteConfigEnabled()) {
-      throw new IllegalStateException("Feature Flagging system started without RC");
+    if (CONFIG_SERVICE != null) {
+      CONFIG_SERVICE.init();
     }
-    CONFIG_SERVICE = new RemoteConfigServiceImpl(sco, config);
-    CONFIG_SERVICE.init();
 
     EXPOSURE_WRITER = new ExposureWriterImpl(sco, config);
     EXPOSURE_WRITER.init();
 
     LOGGER.debug("Feature Flagging system started");
   }
 
+  static ConfigurationSourceService createConfigurationSourceService(
+      final SharedCommunicationObjects sco, final Config config) {
+    final ConfigurationSource configurationSource =
+        ConfigurationSource.from(config.getFeatureFlaggingConfigurationSource());
+
+    switch (configurationSource) {
+      case REMOTE_CONFIG:
+        if (!config.isRemoteConfigEnabled()) {
+          throw new IllegalStateException("Feature Flagging system started without RC");
+        }
+        return new RemoteConfigServiceImpl(sco, config);
+      case AGENTLESS:
+        return new AgentlessConfigurationSource(config);
+      case OFFLINE:
+        LOGGER.debug(
+            "Feature Flagging offline configuration source selected; no config service started");
+        return null;
+      default:
+        throw new IllegalArgumentException(
+            "Unsupported Feature Flagging configuration source: "
+                + config.getFeatureFlaggingConfigurationSource());
+    }
+  }
+
   public static void stop() {
     if (EXPOSURE_WRITER != null) {
       EXPOSURE_WRITER.close();
@@ -41,4 +64,26 @@ public static void stop() {
     }
     LOGGER.debug("Feature Flagging system stopped");
   }
+
+  private enum ConfigurationSource {
+    AGENTLESS("agentless"),
+    REMOTE_CONFIG("remote_config"),
+    OFFLINE("offline");
+
+    private final String value;
+
+    ConfigurationSource(final String value) {
+      this.value = value;
+    }
+
+    private static ConfigurationSource from(final String value) {
+      for (final ConfigurationSource source : values()) {
+        if (source.value.equals(value)) {
+          return source;
+        }
+      }
+      throw new IllegalArgumentException(
+          "Unsupported Feature Flagging configuration source: " + value);
+    }
+  }
 }

products/feature-flagging/feature-flagging-agent/src/test/java/com/datadog/featureflag/FeatureFlaggingSystemTest.java

@@ -1,6 +1,9 @@
 package com.datadog.featureflag;
 
+import static datadog.trace.api.config.FeatureFlaggingConfig.FEATURE_FLAGS_CONFIGURATION_SOURCE;
 import static datadog.trace.api.config.RemoteConfigConfig.REMOTE_CONFIGURATION_ENABLED;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
@@ -23,6 +26,8 @@
 class FeatureFlaggingSystemTest {
 
   @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "remote_config")
+  @WithConfig(key = REMOTE_CONFIGURATION_ENABLED, value = "true")
   void testFeatureFlagSystemInitialization() {
     ConfigurationPoller poller = mock(ConfigurationPoller.class);
     DDAgentFeaturesDiscovery discovery = mock(DDAgentFeaturesDiscovery.class);
@@ -48,6 +53,7 @@ void testFeatureFlagSystemInitialization() {
   }
 
   @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "remote_config")
   @WithConfig(key = REMOTE_CONFIGURATION_ENABLED, value = "false")
   void testThatRemoteConfigIsRequired() {
     SharedCommunicationObjects sharedCommunicationObjects = mock(SharedCommunicationObjects.class);
@@ -60,4 +66,57 @@ void testThatRemoteConfigIsRequired() {
       FeatureFlaggingSystem.stop();
     }
   }
+
+  @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "agentless")
+  @WithConfig(key = REMOTE_CONFIGURATION_ENABLED, value = "false")
+  void agentlessConfigurationSourceUsesHttpServiceWithoutRemoteConfig() {
+    assertInstanceOf(
+        AgentlessConfigurationSource.class,
+        FeatureFlaggingSystem.createConfigurationSourceService(
+            sharedCommunicationObjects(), Config.get()));
+  }
+
+  @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "remote_config")
+  @WithConfig(key = REMOTE_CONFIGURATION_ENABLED, value = "true")
+  void explicitRemoteConfigUsesRemoteConfigService() {
+    SharedCommunicationObjects sharedCommunicationObjects = sharedCommunicationObjects();
+    when(sharedCommunicationObjects.configurationPoller(any(Config.class)))
+        .thenReturn(mock(ConfigurationPoller.class));
+
+    assertInstanceOf(
+        RemoteConfigServiceImpl.class,
+        FeatureFlaggingSystem.createConfigurationSourceService(
+            sharedCommunicationObjects, Config.get()));
+  }
+
+  @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "invalid")
+  void invalidConfigurationSourceFailsBeforeStartingNetworkSource() {
+    assertThrows(
+        IllegalArgumentException.class,
+        () ->
+            FeatureFlaggingSystem.createConfigurationSourceService(
+                sharedCommunicationObjects(), Config.get()));
+  }
+
+  @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "offline")
+  void offlineConfigurationSourceDoesNotStartNetworkSource() {
+    assertNull(
+        FeatureFlaggingSystem.createConfigurationSourceService(
+            sharedCommunicationObjects(), Config.get()));
+  }
+
+  private static SharedCommunicationObjects sharedCommunicationObjects() {
+    DDAgentFeaturesDiscovery discovery = mock(DDAgentFeaturesDiscovery.class);
+    when(discovery.supportsEvpProxy()).thenReturn(true);
+    when(discovery.getEvpProxyEndpoint()).thenReturn("/evp_proxy/");
+    SharedCommunicationObjects sharedCommunicationObjects = mock(SharedCommunicationObjects.class);
+    when(sharedCommunicationObjects.featuresDiscovery(any(Config.class))).thenReturn(discovery);
+    sharedCommunicationObjects.agentUrl = HttpUrl.get("http://localhost");
+    sharedCommunicationObjects.agentHttpClient = new OkHttpClient.Builder().build();
+    return sharedCommunicationObjects;
+  }
 }

products/feature-flagging/feature-flagging-api/README.md

@@ -85,5 +85,7 @@ OTEL_EXPORTER_OTLP_PROTOCOL=grpc
 ## Requirements
 
 - Java 11+
-- Datadog Agent with Remote Configuration enabled
-- `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED=true`
+- `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless` uses the Datadog agentless
+  backend. `remote_config` uses the existing Agent Remote Configuration path.
+  `offline` is reserved for startup-provided UFC bytes; until those bytes are
+  implemented, no network source starts and evaluations use defaults.