feat: honor polling interval across process restarts

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/ClientContextImpl.java

@@ -32,21 +32,25 @@ final class ClientContextImpl extends ClientContext {
     private final FeatureFetcher fetcher;
     private final PlatformState platformState;
     private final TaskExecutor taskExecutor;
+    private final PersistentDataStoreWrapper.PerEnvironmentData perEnvironmentData;
 
     ClientContextImpl(
             ClientContext base,
             DiagnosticStore diagnosticStore,
             FeatureFetcher fetcher,
             PlatformState platformState,
-            TaskExecutor taskExecutor
+            TaskExecutor taskExecutor,
+            PersistentDataStoreWrapper.PerEnvironmentData perEnvironmentData
     ) {
         super(base);
         this.diagnosticStore = diagnosticStore;
         this.fetcher = fetcher;
         this.platformState = platformState;
         this.taskExecutor = taskExecutor;
+        this.perEnvironmentData = perEnvironmentData;
     }
 
+    // TODO: consider re-ordering so perEnvironmentData is earlier in list of params
     static ClientContextImpl fromConfig(
             LDConfig config,
             String mobileKey,
@@ -56,7 +60,8 @@ static ClientContextImpl fromConfig(
             LDLogger logger,
             PlatformState platformState,
             IEnvironmentReporter environmentReporter,
-            TaskExecutor taskExecutor
+            TaskExecutor taskExecutor,
+            PersistentDataStoreWrapper.PerEnvironmentData perEnvironmentData
     ) {
         boolean initiallyInBackground = platformState != null && !platformState.isForeground();
         ClientContext minimalContext = new ClientContext(mobileKey, environmentReporter, logger, config,
@@ -82,14 +87,14 @@ static ClientContextImpl fromConfig(
         if (!config.getDiagnosticOptOut()) {
             diagnosticStore = new DiagnosticStore(EventUtil.makeDiagnosticParams(baseClientContext));
         }
-        return new ClientContextImpl(baseClientContext, diagnosticStore, fetcher, platformState, taskExecutor);
+        return new ClientContextImpl(baseClientContext, diagnosticStore, fetcher, platformState, taskExecutor, perEnvironmentData);
     }
 
     public static ClientContextImpl get(ClientContext context) {
         if (context instanceof ClientContextImpl) {
             return (ClientContextImpl)context;
         }
-        return new ClientContextImpl(context, null, null, null, null);
+        return new ClientContextImpl(context, null, null, null, null, null);
     }
 
     public static ClientContextImpl forDataSource(
@@ -119,7 +124,8 @@ public static ClientContextImpl forDataSource(
                 baseContextImpl.getDiagnosticStore(),
                 baseContextImpl.getFetcher(),
                 baseContextImpl.getPlatformState(),
-                baseContextImpl.getTaskExecutor()
+                baseContextImpl.getTaskExecutor(),
+                baseContextImpl.getPerEnvironmentData()
         );
     }
 
@@ -134,7 +140,8 @@ public ClientContextImpl setEvaluationContext(LDContext context) {
             this.diagnosticStore,
             this.fetcher,
             this.platformState,
-            this.taskExecutor
+            this.taskExecutor,
+            this.perEnvironmentData
         );
     }
 
@@ -154,6 +161,10 @@ public TaskExecutor getTaskExecutor() {
         return throwExceptionIfNull(taskExecutor);
     }
 
+    public PersistentDataStoreWrapper.PerEnvironmentData getPerEnvironmentData() {
+        return throwExceptionIfNull(perEnvironmentData);
+    }
+
     private static <T> T throwExceptionIfNull(T o) {
         if (o == null) {
             throw new IllegalStateException(

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/ComponentsImpl.java

@@ -244,30 +244,45 @@ static final class PollingDataSourceBuilderImpl extends PollingDataSourceBuilder
             implements DiagnosticDescription, DataSourceRequiresFeatureFetcher {
         @Override
         public DataSource build(ClientContext clientContext) {
-            clientContext.getDataSourceUpdateSink().setStatus(
-                    clientContext.isInBackground() ? ConnectionInformation.ConnectionMode.BACKGROUND_POLLING :
+            ClientContextImpl clientContextImpl = ClientContextImpl.get(clientContext);
+            clientContextImpl.getDataSourceUpdateSink().setStatus(
+                    clientContextImpl.isInBackground() ? ConnectionInformation.ConnectionMode.BACKGROUND_POLLING :
                             ConnectionInformation.ConnectionMode.POLLING,
                     null
             );
-            int actualPollIntervalMillis = clientContext.isInBackground() ? backgroundPollIntervalMillis :
+
+            int pollInterval = clientContextImpl.isInBackground() ? backgroundPollIntervalMillis :
                     pollIntervalMillis;
-            int initialDelayMillis;
+
+            long initialDelayMillis;
             if (clientContext.isInBackground() && Boolean.FALSE.equals(clientContext.getPreviouslyInBackground())) {
                 // If we're transitioning from foreground to background, then we don't want to do a
                 // poll right away because we already have recent flag data. Start polling *after*
                 // the first background poll interval.
                 initialDelayMillis = backgroundPollIntervalMillis;
             } else {
-                // If we're in the foreground-- or, if we're in the background but we started out
-                // that way rather than transitioning-- then we should do the first poll right away.
-                initialDelayMillis = 0;
+                // TODO: refactor context hashing calls to use a common util
+                String hashed = new ContextHasher().hash(clientContextImpl.getEvaluationContext().getFullyQualifiedKey());
+
+                long lastUpdated = 0; // assume last updated is beginning of time
+                for (ContextIndex.IndexEntry entry : clientContextImpl.getPerEnvironmentData().getIndex().data) {
+                    if (entry.contextId.equals(hashed)) {
+                        lastUpdated = entry.timestamp;
+                    }
+                }
+
+                // To avoid unnecessarily frequent polling requests due to process or application lifecycle, we have added
+                // this initial delay logic. Calculate how much time has passed since the last update, if that is less than
+                // the polling interval, delay by the difference, otherwise 0 delay.
+                long elapsedSinceUpdate = System.currentTimeMillis() - lastUpdated;
+                initialDelayMillis = Math.max(pollInterval - elapsedSinceUpdate, 0);
             }
-            ClientContextImpl clientContextImpl = ClientContextImpl.get(clientContext);
+
             return new PollingDataSource(
-                    clientContext.getEvaluationContext(),
-                    clientContext.getDataSourceUpdateSink(),
+                    clientContextImpl.getEvaluationContext(),
+                    clientContextImpl.getDataSourceUpdateSink(),
                     initialDelayMillis,
-                    actualPollIntervalMillis,
+                    pollInterval,
                     clientContextImpl.getFetcher(),
                     clientContextImpl.getPlatformState(),
                     clientContextImpl.getTaskExecutor(),

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/ContextDataManager.java

@@ -243,6 +243,12 @@ public boolean upsert(@NonNull LDContext context, @NonNull Flag flag) {
 
             String contextId = hashedContextId(context);
             environmentStore.setContextData(contextId, updatedFlags);
+
+            if (index == null) {
+                index = environmentStore.getIndex();
+            }
+            index = index.updateTimestamp(contextId, System.currentTimeMillis());
+            environmentStore.setIndex(index);
         }
 
         Collection<String> updatedFlag = Collections.singletonList(flag.getKey());

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/LDClient.java

@@ -330,7 +330,7 @@ protected LDClient(
         FeatureFetcher fetcher = null;
         if (config.dataSource instanceof ComponentsImpl.DataSourceRequiresFeatureFetcher) {
             ClientContextImpl minimalContext = ClientContextImpl.fromConfig(config, mobileKey,
-                    environmentName, null, initialContext, logger, platformState, environmentReporter, taskExecutor
+                    environmentName, null, initialContext, logger, platformState, environmentReporter, taskExecutor, environmentStore
             );
             fetcher = new HttpFeatureFlagFetcher(minimalContext);
         }
@@ -344,7 +344,8 @@ protected LDClient(
                 logger,
                 platformState,
                 environmentReporter,
-                taskExecutor
+                taskExecutor,
+                environmentStore
         );
 
         this.contextDataManager = new ContextDataManager(

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/PollingDataSource.java

@@ -20,8 +20,8 @@
 final class PollingDataSource implements DataSource {
     private final LDContext currentContext;
     private final DataSourceUpdateSink dataSourceUpdateSink;
-    final int initialDelayMillis; // visible for testing
-    final int pollIntervalMillis; // visible for testing
+    final long initialDelayMillis; // visible for testing
+    final long pollIntervalMillis; // visible for testing
     private final FeatureFetcher fetcher;
     private final PlatformState platformState;
     private final TaskExecutor taskExecutor;
@@ -32,8 +32,8 @@ final class PollingDataSource implements DataSource {
     PollingDataSource(
             LDContext currentContext,
             DataSourceUpdateSink dataSourceUpdateSink,
-            int initialDelayMillis,
-            int pollIntervalMillis,
+            long initialDelayMillis,
+            long pollIntervalMillis,
             FeatureFetcher fetcher,
             PlatformState platformState,
             TaskExecutor taskExecutor,

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/ConnectivityManagerTest.java

@@ -116,7 +116,8 @@ private void createTestManager(
                 logging.logger,
                 mockPlatformState,
                 environmentReporter,
-                taskExecutor
+                taskExecutor,
+                environmentStore
         );
 
         contextDataManager = new ContextDataManager(

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/ContextDataManagerTestBase.java

@@ -55,7 +55,8 @@ protected ContextDataManager createDataManager(int maxCachedContexts) {
                 logging.logger,
                 null,
                 environmentReporter,
-                taskExecutor
+                taskExecutor,
+                environmentStore
         );
         return new ContextDataManager(
                 clientContext,

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/DiagnosticConfigTest.java

@@ -142,7 +142,7 @@ public void customDiagnosticConfigurationHttp() throws Exception {
 
     private static LDValue makeDiagnosticJson(LDConfig config) throws Exception {
         ClientContext clientContext = ClientContextImpl.fromConfig(config, "", "",
-                null, null, LDLogger.none(), null, new EnvironmentReporterBuilder().build(), null);
+                null, null, LDLogger.none(), null, new EnvironmentReporterBuilder().build(), null, null);
         DiagnosticStore.SdkDiagnosticParams params = EventUtil.makeDiagnosticParams(clientContext);
         DiagnosticStore diagnosticStore = new DiagnosticStore(params);
         MockDiagnosticEventSender mockSender = new MockDiagnosticEventSender();

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/LDConfigTest.java

@@ -75,7 +75,7 @@ Map<String, String> headersToMap(Headers headers) {
     public void headersForEnvironment() {
         LDConfig config = new LDConfig.Builder(AutoEnvAttributes.Disabled).mobileKey("test-key").build();
         ClientContext clientContext = ClientContextImpl.fromConfig(config, "test-key", "",
-                null, null, null, null, new EnvironmentReporterBuilder().build(), null);
+                null, null, null, null, new EnvironmentReporterBuilder().build(), null, null);
         Map<String, String> headers = headersToMap(
                 LDUtil.makeHttpProperties(clientContext).toHeadersBuilder().build()
         );
@@ -96,7 +96,7 @@ public void headersForEnvironmentWithTransform() {
                 }))
                 .build();
         ClientContext clientContext = ClientContextImpl.fromConfig(config, "test-key", "",
-                null, null, null, null, new EnvironmentReporterBuilder().build(), null);
+                null, null, null, null, new EnvironmentReporterBuilder().build(), null, null);
 
         expected.put("User-Agent", LDUtil.USER_AGENT_HEADER_VALUE);
         expected.put("Authorization", "api_key test-key");

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/PollingDataSourceTest.java

@@ -3,6 +3,7 @@
 import static com.launchdarkly.sdk.android.AssertHelpers.requireNoMoreValues;
 import static com.launchdarkly.sdk.android.AssertHelpers.requireValue;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
 
 import com.launchdarkly.sdk.LDContext;
 import com.launchdarkly.sdk.LDValue;
@@ -15,6 +16,7 @@
 import com.launchdarkly.sdk.android.subsystems.DataSource;
 
 import org.easymock.EasyMockSupport;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
@@ -24,8 +26,9 @@
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
-public class PollingDataSourceTest extends EasyMockSupport {
+public class PollingDataSourceTest {
     private static final LDContext CONTEXT = LDContext.create("context-key");
+    private static final String MOBILE_KEY = "test-mobile-key";
     private static final LDConfig EMPTY_CONFIG = new LDConfig.Builder(AutoEnvAttributes.Disabled).build();
 
     private final MockComponents.MockDataSourceUpdateSink dataSourceUpdateSink = new MockComponents.MockDataSourceUpdateSink();
@@ -34,14 +37,20 @@ public class PollingDataSourceTest extends EasyMockSupport {
 
     private final IEnvironmentReporter environmentReporter = new EnvironmentReporterBuilder().build();
     private final SimpleTestTaskExecutor taskExecutor = new SimpleTestTaskExecutor();
+    private PersistentDataStoreWrapper.PerEnvironmentData perEnvironmentData;
 
     @Rule
     public LogCaptureRule logging = new LogCaptureRule();
 
-    private ClientContext makeClientContext(boolean inBackground, Boolean previouslyInBackground) {
-        ClientContext baseClientContext = ClientContextImpl.fromConfig(
+    @Before
+    public void before() {
+        perEnvironmentData = TestUtil.makeSimplePersistentDataStoreWrapper().perEnvironmentData(MOBILE_KEY);
+    }
+
+    private ClientContextImpl makeClientContext(boolean inBackground, Boolean previouslyInBackground) {
+        ClientContextImpl baseClientContext = ClientContextImpl.fromConfig(
                 EMPTY_CONFIG, "", "", fetcher, CONTEXT,
-                logging.logger, platformState, environmentReporter, taskExecutor);
+                logging.logger, platformState, environmentReporter, taskExecutor, perEnvironmentData);
         return ClientContextImpl.forDataSource(
                 baseClientContext,
                 dataSourceUpdateSink,
@@ -115,6 +124,27 @@ public void firstPollIsImmediateWhenStartingInBackground() throws Exception {
         }
     }
 
+    @Test
+    public void pollingIntervalHonoredAcrossMultipleBuildCalls() throws Exception {
+        ClientContextImpl clientContext = makeClientContext(true, null);
+        PollingDataSourceBuilder builder = Components.pollingDataSource()
+                .pollIntervalMillis(100000)
+                .backgroundPollIntervalMillis(100000);
+
+        // first build should have no delay
+        PollingDataSource ds1 = (PollingDataSource) builder.build(clientContext);
+        assertEquals(0, ds1.initialDelayMillis);
+
+        // simulate successful update of context index timestamp
+        String hash = new ContextHasher().hash(CONTEXT.getFullyQualifiedKey());
+        ContextIndex newIndex = clientContext.getPerEnvironmentData().getIndex().updateTimestamp(hash, System.currentTimeMillis());
+        clientContext.getPerEnvironmentData().setIndex(newIndex);
+
+        // second build should have a non-zero delay due to simulated response storing a recent timestamp
+        PollingDataSource ds2 = (PollingDataSource) builder.build(clientContext);
+        assertNotEquals(0, ds2.initialDelayMillis);
+    }
+
     @Test
     public void firstPollHappensAfterBackgroundPollingIntervalWhenTransitioningToBackground() throws Exception {
         ClientContext clientContext = makeClientContext(true, false);

launchdarkly-android-client-sdk/src/test/java/com/launchdarkly/sdk/android/StreamingDataSourceTest.java

@@ -11,6 +11,7 @@
 import com.launchdarkly.sdk.android.subsystems.ClientContext;
 import com.launchdarkly.sdk.android.subsystems.DataSource;
 
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
@@ -23,20 +24,24 @@ public class StreamingDataSourceTest {
     // the tests here cover other aspects of how the streaming data source component behaves.
 
     private static final LDContext CONTEXT = LDContext.create("context-key");
-
+    private static final String MOBILE_KEY = "test-mobile-key";
     @Rule
     public LogCaptureRule logging = new LogCaptureRule();
-
     private final MockComponents.MockDataSourceUpdateSink dataSourceUpdateSink = new MockComponents.MockDataSourceUpdateSink();
     private final MockPlatformState platformState = new MockPlatformState();
-
     private final IEnvironmentReporter environmentReporter = new EnvironmentReporterBuilder().build();
     private final SimpleTestTaskExecutor taskExecutor = new SimpleTestTaskExecutor();
+    private PersistentDataStoreWrapper.PerEnvironmentData perEnvironmentData;
+
+    @Before
+    public void before() {
+        perEnvironmentData = TestUtil.makeSimplePersistentDataStoreWrapper().perEnvironmentData(MOBILE_KEY);
+    }
 
     private ClientContext makeClientContext(boolean inBackground, Boolean previouslyInBackground) {
         ClientContext baseClientContext = ClientContextImpl.fromConfig(
                 new LDConfig.Builder(AutoEnvAttributes.Disabled).build(), "", "", null, CONTEXT,
-                logging.logger, platformState, environmentReporter, taskExecutor);
+                logging.logger, platformState, environmentReporter, taskExecutor, perEnvironmentData);
         return ClientContextImpl.forDataSource(
                 baseClientContext,
                 dataSourceUpdateSink,
@@ -53,7 +58,7 @@ private ClientContext makeClientContext(boolean inBackground, Boolean previously
     private ClientContext makeClientContextWithFetcher() {
         ClientContext baseClientContext = ClientContextImpl.fromConfig(
                 new LDConfig.Builder(AutoEnvAttributes.Disabled).build(), "", "", makeFeatureFetcher(), CONTEXT,
-                logging.logger, platformState, environmentReporter, taskExecutor);
+                logging.logger, platformState, environmentReporter, taskExecutor, perEnvironmentData);
         return ClientContextImpl.forDataSource(
                 baseClientContext,
                 dataSourceUpdateSink,