Move feature flagging evaluation into provider runtime

Author: leoromanovsky

dd-smoke-tests/openfeature/application/build.gradle

@@ -31,8 +31,9 @@ if (hasProperty('featureFlaggingApiJar')) {
 }
 
 dependencies {
-  // OpenFeature SDK is an API dependency of feature-flagging-api but is not
-  // transitively resolved when the jar is passed as a files() dependency.
+  // Maven resolves these provider dependencies from the published POM. This smoke test uses the
+  // provider as a files() dependency, so it must declare them explicitly.
   implementation 'dev.openfeature:sdk:1.20.1'
+  implementation 'com.squareup.moshi:moshi:1.11.0'
   implementation 'org.springframework.boot:spring-boot-starter-web'
 }

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

@@ -70,10 +70,6 @@ private static synchronized void activateAgentless(
 
   private static void initializeSystem(final SharedCommunicationObjects sco, final Config config) {
     final ConfigurationSourceService configService = createConfigurationSourceService(sco, config);
-    if (configService == null) {
-      LOGGER.debug("Feature Flagging system disabled by unsupported configuration source");
-      return;
-    }
     final ExposureWriter exposureWriter = new ExposureWriterImpl(sco, config);
     initialize(configService, exposureWriter);
 
@@ -119,7 +115,8 @@ static ConfigurationSourceService createConfigurationSourceService(
       return new RemoteConfigServiceImpl(sco, config);
     }
     if (CONFIGURATION_SOURCE_AGENTLESS.equals(configurationSource)) {
-      return new AgentlessConfigurationSource(config);
+      // CDN delivery belongs to the application provider. The agent owns telemetry only.
+      return null;
     }
     return null;
   }

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

@@ -21,7 +21,7 @@
 import datadog.communication.ddagent.DDAgentFeaturesDiscovery;
 import datadog.communication.ddagent.SharedCommunicationObjects;
 import datadog.remoteconfig.Capabilities;
-import datadog.remoteconfig.ConfigurationDeserializer;
+import datadog.remoteconfig.ConfigurationChangesListener;
 import datadog.remoteconfig.ConfigurationPoller;
 import datadog.remoteconfig.Product;
 import datadog.trace.api.Config;
@@ -99,7 +99,7 @@ void testFeatureFlagSystemInitialization() {
     FeatureFlaggingSystem.start(sharedCommunicationObjects);
 
     verify(poller).addCapabilities(Capabilities.CAPABILITY_FFE_FLAG_CONFIGURATION_RULES);
-    verify(poller).addListener(eq(Product.FFE_FLAGS), any(ConfigurationDeserializer.class), any());
+    verify(poller).addListener(eq(Product.FFE_FLAGS), any(ConfigurationChangesListener.class));
     verify(poller).start();
 
     FeatureFlaggingSystem.stop();
@@ -128,9 +128,8 @@ void testThatRemoteConfigIsRequired() {
   @Test
   @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "agentless")
   @WithConfig(key = REMOTE_CONFIGURATION_ENABLED, value = "false")
-  void agentlessConfigurationSourceUsesHttpServiceWithoutRemoteConfig() {
-    assertInstanceOf(
-        AgentlessConfigurationSource.class,
+  void agentlessConfigurationSourceIsProviderOwned() {
+    assertNull(
         FeatureFlaggingSystem.createConfigurationSourceService(
             sharedCommunicationObjects(), Config.get()));
   }

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

@@ -85,19 +85,23 @@ OTEL_EXPORTER_OTLP_PROTOCOL=grpc
 ## Requirements
 
 - Java 11+
-- `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless` uses the Datadog agentless
-  backend. Set `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_BASE_URL` to a
-  different HTTP backend while keeping agentless delivery semantics. A bare
-  host uses the standard rules-based server path; a URL with a path is used as
-  the exact UFC endpoint. Configured URLs are opaque: the SDK does not add the
-  Datadog-managed `dd_env` query parameter, so custom backends must include any
-  required tenant or environment scope in the configured URL. The derived
-  Datadog-managed endpoint is
-  `https://ufc-server.ff-cdn.<site>/api/v2/feature-flagging/config/rules-based/server`
-  and expects UFC under the JSON:API `data.attributes` response member. It is
-  intended for supported commercial sites; use an explicit base URL elsewhere.
-  Agentless responses do not have an SDK-imposed payload-size limit.
-  `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.
+
+CDN delivery is the default configuration source. It requires `dd-openfeature`. It does not
+require the Datadog Java agent.
+
+`DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless` selects the same CDN delivery mode. Set
+`DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_BASE_URL` to use a different HTTP endpoint.
+A root URL uses the standard rules-based server path. A URL with a path is the exact UFC endpoint.
+
+The managed endpoint is:
+
+`https://ufc-server.ff-cdn.<site>/api/v2/feature-flagging/config/rules-based/server`
+
+The managed endpoint returns UFC under the JSON:API `data.attributes` member.
+
+`DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=remote_config` selects Remote Configuration. This mode
+requires a compatible Datadog Java agent. Java agent version 1.65.0 adds the raw UFC bridge for this
+provider version. An older agent produces a clear provider initialization error.
+
+Offline startup bytes are a future configuration source. This version does not support offline
+delivery.

products/feature-flagging/feature-flagging-api/build.gradle.kts

@@ -1,5 +1,7 @@
 import datadog.gradle.plugin.testJvmConstraints.TestJvmConstraintsExtension
 import groovy.lang.Closure
+import org.gradle.api.tasks.SourceSetContainer
+import java.util.zip.ZipFile
 
 plugins {
   `java-library`
@@ -16,6 +18,11 @@ configure<TestJvmConstraintsExtension> {
 
 description = "Implementation of the OpenFeature Provider interface."
 
+// This module is an adapter and lifecycle boundary. Core evaluation and HTTP behavior have
+// stronger module-local gates. Child JVM tests cover classloader and no-agent behavior here.
+extra["minimumBranchCoverage"] = 0.4
+extra["minimumInstructionCoverage"] = 0.6
+
 // Set both JAR and Maven artifact name
 val openFeatureArtifactId = "dd-openfeature"
 base {
@@ -42,14 +49,16 @@ java {
 
 dependencies {
   api("dev.openfeature:sdk:1.20.1")
+  implementation(libs.moshi)
+  implementation(libs.slf4j)
 
-  compileOnly(project(":products:feature-flagging:feature-flagging-bootstrap"))
-  compileOnly(project(":products:feature-flagging:feature-flagging-config"))
-  compileOnly(project(":utils:config-utils"))
+  compileOnly(project(":products:feature-flagging:feature-flagging-core"))
+  compileOnly(project(":products:feature-flagging:feature-flagging-http"))
   compileOnly("io.opentelemetry:opentelemetry-api:1.47.0")
 
   testImplementation(project(":products:feature-flagging:feature-flagging-bootstrap"))
-  testImplementation(project(":utils:config-utils"))
+  testImplementation(project(":products:feature-flagging:feature-flagging-core"))
+  testImplementation(project(":products:feature-flagging:feature-flagging-http"))
   testImplementation("io.opentelemetry:opentelemetry-api:1.47.0")
   testImplementation(libs.bundles.junit5)
   testImplementation(libs.bundles.mockito)
@@ -78,8 +87,61 @@ tasks.withType<Javadoc>().configureEach {
   javadocTool = javaToolchains.javadocToolFor(java.toolchain)
 }
 
+val coreProject = project(":products:feature-flagging:feature-flagging-core")
+val httpProject = project(":products:feature-flagging:feature-flagging-http")
+
+tasks.named<Jar>("jar") {
+  from(coreProject.extensions.getByType<SourceSetContainer>().named("main").map { it.output })
+  from(httpProject.extensions.getByType<SourceSetContainer>().named("main").map { it.output })
+}
+
 // The dd-openfeature provider jar is not produced by the CI `build` job, so there is no reference
 // artifact to compare against. Disable the release jar comparison gate registered by publish.gradle.
 tasks.named("compareToReferenceJar") {
   enabled = false
 }
+
+tasks.register("verifyDdOpenfeatureArtifact") {
+  dependsOn(tasks.named("jar"), tasks.named("generatePomFileForMavenPublication"))
+  doLast {
+    val providerJar = tasks.named<Jar>("jar").get().archiveFile.get().asFile
+    val requiredEntries = setOf(
+      "datadog/openfeature/internal/core/ConfigurationStore.class",
+      "datadog/openfeature/internal/core/FlagEvaluator.class",
+      "datadog/openfeature/internal/http/CdnConfigurationSource.class",
+      "datadog/openfeature/internal/http/HttpConfigurationOptions.class"
+    )
+    val forbiddenReferences = setOf(
+      "datadog/trace/api/featureflag/ufc",
+      "datadog/trace/api/featureflag/FeatureFlaggingGateway",
+      "datadog/trace/api/Config",
+      "datadog/trace/util/AgentThread",
+      "datadog/communication/http"
+    )
+    ZipFile(providerJar).use { zip ->
+      val entryNames = zip.entries().asSequence().map { it.name }.toSet()
+      val missing = requiredEntries - entryNames
+      check(missing.isEmpty()) {
+        "dd-openfeature is missing embedded provider classes: $missing"
+      }
+      zip.entries().asSequence()
+        .filter { it.name.endsWith(".class") }
+        .forEach { entry ->
+          val classBytes = zip.getInputStream(entry).readBytes().toString(Charsets.ISO_8859_1)
+          forbiddenReferences.forEach { reference ->
+            check(!classBytes.contains(reference)) {
+              "dd-openfeature class ${entry.name} references forbidden agent class $reference"
+            }
+          }
+        }
+    }
+
+    val pom = layout.buildDirectory.file("publications/maven/pom-default.xml").get().asFile
+    check(pom.isFile) { "Generated dd-openfeature Maven POM is missing" }
+    val pomText = pom.readText()
+    check(pomText.contains("<artifactId>sdk</artifactId>"))
+    check(pomText.contains("<artifactId>moshi</artifactId>"))
+    check(!pomText.contains("feature-flagging-core"))
+    check(!pomText.contains("feature-flagging-http"))
+  }
+}

products/feature-flagging/feature-flagging-api/gradle.lockfile

@@ -11,8 +11,8 @@ com.github.stephenc.jcip:jcip-annotations:1.0-1=spotbugs
 com.google.code.findbugs:jsr305:3.0.2=compileClasspath,spotbugs,testCompileClasspath,testRuntimeClasspath
 com.google.code.gson:gson:2.13.2=spotbugs
 com.google.errorprone:error_prone_annotations:2.41.0=spotbugs
-com.squareup.moshi:moshi:1.11.0=testCompileClasspath,testRuntimeClasspath
-com.squareup.okio:okio:1.17.5=testCompileClasspath,testRuntimeClasspath
+com.squareup.moshi:moshi:1.11.0=compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
+com.squareup.okio:okio:1.17.5=compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
 com.thoughtworks.qdox:qdox:1.12.1=codenarc
 commons-io:commons-io:2.20.0=spotbugs
 de.thetaphi:forbiddenapis:3.10=compileClasspath
@@ -57,7 +57,6 @@ org.junit.jupiter:junit-jupiter:5.14.1=testCompileClasspath,testRuntimeClasspath
 org.junit.platform:junit-platform-commons:1.14.1=testCompileClasspath,testRuntimeClasspath
 org.junit.platform:junit-platform-engine:1.14.1=testCompileClasspath,testRuntimeClasspath
 org.junit.platform:junit-platform-launcher:1.14.1=testRuntimeClasspath
-org.junit:junit-bom:5.14.0=spotbugs
 org.junit:junit-bom:5.14.1=testCompileClasspath,testRuntimeClasspath
 org.mockito:mockito-core:4.4.0=testCompileClasspath,testRuntimeClasspath
 org.mockito:mockito-junit-jupiter:4.4.0=testCompileClasspath,testRuntimeClasspath
@@ -76,7 +75,6 @@ org.slf4j:jul-to-slf4j:1.7.30=testCompileClasspath,testRuntimeClasspath
 org.slf4j:log4j-over-slf4j:1.7.30=testCompileClasspath,testRuntimeClasspath
 org.slf4j:slf4j-api:2.0.17=compileClasspath,runtimeClasspath,spotbugs,spotbugsSlf4j,testCompileClasspath,testRuntimeClasspath
 org.slf4j:slf4j-simple:2.0.17=spotbugsSlf4j
-org.snakeyaml:snakeyaml-engine:2.9=testRuntimeClasspath
 org.spockframework:spock-bom:2.4-groovy-3.0=testCompileClasspath,testRuntimeClasspath
 org.spockframework:spock-core:2.4-groovy-3.0=testCompileClasspath,testRuntimeClasspath
 org.tabletest:tabletest-junit:1.2.1=testCompileClasspath,testRuntimeClasspath