Fix agentless feature flagging CI coverage

Author: leoromanovsky

dd-smoke-tests/openfeature/src/test/groovy/datadog/smoketest/springboot/OpenFeatureProviderSmokeTest.groovy

@@ -42,6 +42,7 @@ class OpenFeatureProviderSmokeTest extends AbstractServerSmokeTest {
     command.addAll(['-jar', springBootShadowJar, "--server.port=${httpPort}".toString()])
     final builder = new ProcessBuilder(command).directory(new File(buildDirectory))
     builder.environment().put('DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED', 'true')
+    builder.environment().put('DD_FEATURE_FLAGS_CONFIGURATION_SOURCE', 'remote_config')
     return builder
   }
 

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

@@ -34,23 +34,18 @@ static ConfigurationSourceService createConfigurationSourceService(
     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());
+    if (configurationSource == ConfigurationSource.REMOTE_CONFIG) {
+      if (!config.isRemoteConfigEnabled()) {
+        throw new IllegalStateException("Feature Flagging system started without RC");
+      }
+      return new RemoteConfigServiceImpl(sco, config);
+    }
+    if (configurationSource == ConfigurationSource.AGENTLESS) {
+      return new AgentlessConfigurationSource(config);
     }
+    LOGGER.debug(
+        "Feature Flagging offline configuration source selected; no config service started");
+    return null;
   }
 
   public static void stop() {

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

@@ -2,6 +2,7 @@
 
 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.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -109,6 +110,16 @@ void offlineConfigurationSourceDoesNotStartNetworkSource() {
             sharedCommunicationObjects(), Config.get()));
   }
 
+  @Test
+  @WithConfig(key = FEATURE_FLAGS_CONFIGURATION_SOURCE, value = "offline")
+  void startWithOfflineConfigurationSourceSkipsConfigService() {
+    try {
+      assertDoesNotThrow(() -> FeatureFlaggingSystem.start(sharedCommunicationObjects()));
+    } finally {
+      FeatureFlaggingSystem.stop();
+    }
+  }
+
   private static SharedCommunicationObjects sharedCommunicationObjects() {
     DDAgentFeaturesDiscovery discovery = mock(DDAgentFeaturesDiscovery.class);
     when(discovery.supportsEvpProxy()).thenReturn(true);

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

@@ -113,7 +113,7 @@ private void pollOnceSafely() {
   }
 
   private boolean fetchAndApply() {
-    for (int attempt = 1; attempt <= MAX_ATTEMPTS; attempt++) {
+    for (int attempt = 1; ; attempt++) {
       try {
         final UfcHttpResponse response = client.fetch(endpoint, config, etag);
         if (isRetryableStatus(response.status) && attempt < MAX_ATTEMPTS) {
@@ -127,7 +127,6 @@ private boolean fetchAndApply() {
         }
       }
     }
-    return false;
   }
 
   private boolean apply(final UfcHttpResponse response) {
@@ -220,10 +219,10 @@ static final class UfcHttpResponse {
     }
   }
 
-  private static final class OkHttpUfcHttpClient implements UfcHttpClient {
+  static final class OkHttpUfcHttpClient implements UfcHttpClient {
     private final OkHttpClient httpClient;
 
-    private OkHttpUfcHttpClient(final OkHttpClient httpClient) {
+    OkHttpUfcHttpClient(final OkHttpClient httpClient) {
       this.httpClient = httpClient;
     }
 
@@ -237,15 +236,12 @@ public UfcHttpResponse fetch(final HttpUrl endpoint, final Config config, final
       final Request request = prepareRequest(endpoint, headers, config, true).get().build();
       try (Response response = httpClient.newCall(request).execute()) {
         final ResponseBody responseBody = response.body();
-        return new UfcHttpResponse(
-            response.code(),
-            response.header("ETag"),
-            responseBody == null ? null : responseBody.bytes());
+        return new UfcHttpResponse(response.code(), response.header("ETag"), responseBody.bytes());
       }
     }
   }
 
-  private static final class UfcHttpThreadFactory implements ThreadFactory {
+  static final class UfcHttpThreadFactory implements ThreadFactory {
     @Override
     public Thread newThread(final Runnable runnable) {
       final Thread thread = new Thread(runnable, "dd-feature-flagging-http-poller");