Send feature flag SDK identity in request headers

communication/src/main/java/datadog/communication/BackendApiFactory.java

@@ -1,13 +1,20 @@
 package datadog.communication;
 
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.unmodifiableMap;
+
 import datadog.communication.ddagent.DDAgentFeaturesDiscovery;
 import datadog.communication.ddagent.SharedCommunicationObjects;
 import datadog.communication.http.HttpRetryPolicy;
 import datadog.trace.api.Config;
 import datadog.trace.api.intake.Intake;
 import datadog.trace.util.throwable.FatalAgentMisconfigurationError;
+import java.util.HashMap;
+import java.util.Map;
 import javax.annotation.Nullable;
 import okhttp3.HttpUrl;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -17,10 +24,19 @@ public class BackendApiFactory {
 
   private final Config config;
   private final SharedCommunicationObjects sharedCommunicationObjects;
+  private final Map<String, String> requestHeaders;
 
   public BackendApiFactory(Config config, SharedCommunicationObjects sharedCommunicationObjects) {
+    this(config, sharedCommunicationObjects, emptyMap());
+  }
+
+  public BackendApiFactory(
+      Config config,
+      SharedCommunicationObjects sharedCommunicationObjects,
+      Map<String, String> requestHeaders) {
     this.config = config;
     this.sharedCommunicationObjects = sharedCommunicationObjects;
+    this.requestHeaders = unmodifiableMap(new HashMap<>(requestHeaders));
   }
 
   public @Nullable BackendApi createBackendApi(Intake intake) {
@@ -60,7 +76,7 @@ public BackendApi createDirectIntakeApi(Intake intake, boolean responseCompressi
         apiKey,
         traceId,
         retryPolicyFactory(),
-        sharedCommunicationObjects.getIntakeHttpClient(),
+        withRequestHeaders(sharedCommunicationObjects.getIntakeHttpClient()),
         responseCompression);
   }
 
@@ -98,10 +114,27 @@ public BackendApi createDirectIntakeApi(Intake intake, boolean responseCompressi
         evpProxyUrl,
         subdomain,
         retryPolicyFactory,
-        sharedCommunicationObjects.agentHttpClient,
+        withRequestHeaders(sharedCommunicationObjects.agentHttpClient),
         responseCompression);
   }
 
+  private OkHttpClient withRequestHeaders(final OkHttpClient httpClient) {
+    if (requestHeaders.isEmpty()) {
+      return httpClient;
+    }
+    return httpClient
+        .newBuilder()
+        .addInterceptor(
+            chain -> {
+              final Request.Builder requestBuilder = chain.request().newBuilder();
+              for (Map.Entry<String, String> header : requestHeaders.entrySet()) {
+                requestBuilder.header(header.getKey(), header.getValue());
+              }
+              return chain.proceed(requestBuilder.build());
+            })
+        .build();
+  }
+
   private static HttpRetryPolicy.Factory retryPolicyFactory() {
     return new HttpRetryPolicy.Factory(5, 100, 2.0, true);
   }

communication/src/test/java/datadog/communication/BackendApiFactoryTest.java

@@ -1,6 +1,7 @@
 package datadog.communication;
 
 import static datadog.communication.ddagent.DDAgentFeaturesDiscovery.V4_EVP_PROXY_ENDPOINT;
+import static java.util.Collections.singletonMap;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -45,7 +46,9 @@ void advertisedEvpProxyEndpointSupportsDisabledResponseCompression() throws Exce
       final FakeFeaturesDiscovery discovery = new FakeFeaturesDiscovery(V4_EVP_PROXY_ENDPOINT);
       final BackendApiFactory factory =
           new BackendApiFactory(
-              Config.get(), sharedCommunicationObjects(discovery, agent.url("/")));
+              Config.get(),
+              sharedCommunicationObjects(discovery, agent.url("/")),
+              singletonMap("DD-EVP-ORIGIN", "dd-trace-java"));
       final BackendApi api = factory.createBackendApi(Intake.EVENT_PLATFORM, false);
 
       assertNotNull(api);
@@ -58,6 +61,9 @@ void advertisedEvpProxyEndpointSupportsDisabledResponseCompression() throws Exce
 
       final RecordedRequest request = agent.takeRequest();
       assertEquals("/evp_proxy/v4/api/v2/flagevaluation", request.getPath());
+      assertEquals("event-platform-intake", request.getHeader("X-Datadog-EVP-Subdomain"));
+      assertEquals("dd-trace-java", request.getHeader("DD-EVP-ORIGIN"));
+      assertEquals("identity", request.getHeader("Accept-Encoding"));
     } finally {
       agent.shutdown();
     }

products/feature-flagging/feature-flagging-lib/src/main/java/com/datadog/featureflag/FeatureFlagBackendApiFactory.java

@@ -1,13 +1,17 @@
 package com.datadog.featureflag;
 
 import static datadog.trace.api.featureflag.config.FeatureFlaggingConfig.CONFIGURATION_SOURCE_AGENTLESS;
+import static java.util.Collections.unmodifiableMap;
 
 import datadog.communication.BackendApi;
 import datadog.communication.BackendApiFactory;
 import datadog.communication.ddagent.SharedCommunicationObjects;
+import datadog.communication.ddagent.TracerVersion;
 import datadog.communication.http.HttpRetryPolicy;
 import datadog.trace.api.Config;
 import datadog.trace.api.intake.Intake;
+import java.util.HashMap;
+import java.util.Map;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -16,6 +20,7 @@
 final class FeatureFlagBackendApiFactory {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(FeatureFlagBackendApiFactory.class);
+  static final Map<String, String> REQUEST_HEADERS = requestHeaders();
 
   private final Config config;
   private final BackendApiFactory backendApiFactory;
@@ -25,7 +30,10 @@ final class FeatureFlagBackendApiFactory {
       final Config config,
       final SharedCommunicationObjects sharedCommunicationObjects,
       final FeatureFlagEventType eventType) {
-    this(config, new BackendApiFactory(config, sharedCommunicationObjects), eventType);
+    this(
+        config,
+        new BackendApiFactory(config, sharedCommunicationObjects, REQUEST_HEADERS),
+        eventType);
   }
 
   FeatureFlagBackendApiFactory(
@@ -78,6 +86,13 @@ BackendApi create() {
     return null;
   }
 
+  private static Map<String, String> requestHeaders() {
+    final Map<String, String> headers = new HashMap<>(2);
+    headers.put("DD-EVP-ORIGIN", "dd-trace-java");
+    headers.put("DD-EVP-ORIGIN-VERSION", TracerVersion.TRACER_VERSION);
+    return unmodifiableMap(headers);
+  }
+
   private boolean hasDirectCredentials() {
     final String apiKey = config.getApiKey();
     return apiKey != null && !apiKey.isEmpty();

products/feature-flagging/feature-flagging-lib/src/test/java/com/datadog/featureflag/FeatureFlagBackendApiFactoryTest.java

@@ -4,6 +4,7 @@
 import static com.datadog.featureflag.FeatureFlagEventType.FLAG_EVALUATION;
 import static datadog.trace.api.featureflag.config.FeatureFlaggingConfig.CONFIGURATION_SOURCE_AGENTLESS;
 import static datadog.trace.api.featureflag.config.FeatureFlaggingConfig.CONFIGURATION_SOURCE_REMOTE_CONFIG;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
@@ -14,13 +15,23 @@
 
 import datadog.communication.BackendApi;
 import datadog.communication.BackendApiFactory;
+import datadog.communication.ddagent.TracerVersion;
 import datadog.communication.http.HttpRetryPolicy;
 import datadog.trace.api.Config;
 import datadog.trace.api.intake.Intake;
 import org.junit.jupiter.api.Test;
 
 class FeatureFlagBackendApiFactoryTest {
 
+  @Test
+  void configuresSdkIdentityHeadersForAllFeatureFlagEventTypes() {
+    assertEquals(
+        "dd-trace-java", FeatureFlagBackendApiFactory.REQUEST_HEADERS.get("DD-EVP-ORIGIN"));
+    assertEquals(
+        TracerVersion.TRACER_VERSION,
+        FeatureFlagBackendApiFactory.REQUEST_HEADERS.get("DD-EVP-ORIGIN-VERSION"));
+  }
+
   @Test
   void remoteConfigUsesOnlyLocalEvpProxy() {
     final Config config = config(CONFIGURATION_SOURCE_REMOTE_CONFIG, "api-key");