feat: Obey HTTP Status codes from upstream.

.github/workflows/pull_requests.yml

@@ -10,7 +10,7 @@ jobs:
         version: [8,11,17]
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Setup Java
         uses: actions/setup-java@v3
         with:

src/main/java/io/getunleash/metric/DefaultHttpMetricsSender.java

@@ -37,26 +37,32 @@ public DefaultHttpMetricsSender(UnleashConfig unleashConfig) {
                         .create();
     }
 
-    public void registerClient(ClientRegistration registration) {
+    public int registerClient(ClientRegistration registration) {
         if (!unleashConfig.isDisableMetrics()) {
             try {
-                post(clientRegistrationURL, registration);
+                int statusCode = post(clientRegistrationURL, registration);
                 eventDispatcher.dispatch(registration);
+                return statusCode;
             } catch (UnleashException ex) {
                 eventDispatcher.dispatch(ex);
+                return -1;
             }
         }
+        return -1;
     }
 
-    public void sendMetrics(ClientMetrics metrics) {
+    public int sendMetrics(ClientMetrics metrics) {
         if (!unleashConfig.isDisableMetrics()) {
             try {
-                post(clientMetricsURL, metrics);
+                int statusCode = post(clientMetricsURL, metrics);
                 eventDispatcher.dispatch(metrics);
+                return statusCode;
             } catch (UnleashException ex) {
                 eventDispatcher.dispatch(ex);
+                return -1;
             }
         }
+        return -1;
     }
 
     private int post(URL url, Object o) throws UnleashException {

src/main/java/io/getunleash/metric/MetricSender.java

@@ -1,7 +1,7 @@
 package io.getunleash.metric;
 
 public interface MetricSender {
-    void registerClient(ClientRegistration registration);
+    int registerClient(ClientRegistration registration);
 
-    void sendMetrics(ClientMetrics metrics);
+    int sendMetrics(ClientMetrics metrics);
 }

src/main/java/io/getunleash/metric/OkHttpMetricsSender.java

@@ -60,19 +60,21 @@ public OkHttpMetricsSender(UnleashConfig config) {
     }
 
     @Override
-    public void registerClient(ClientRegistration registration) {
+    public int registerClient(ClientRegistration registration) {
         if (!config.isDisableMetrics()) {
             try {
-                post(clientRegistrationUrl, registration);
+                int statusCode = post(clientRegistrationUrl, registration);
                 eventDispatcher.dispatch(registration);
+                return statusCode;
             } catch (UnleashException ex) {
                 eventDispatcher.dispatch(ex);
             }
         }
+        return -1;
     }
 
     @Override
-    public void sendMetrics(ClientMetrics metrics) {
+    public int sendMetrics(ClientMetrics metrics) {
         if (!config.isDisableMetrics()) {
             try {
                 post(clientMetricsUrl, metrics);
@@ -81,6 +83,7 @@ public void sendMetrics(ClientMetrics metrics) {
                 eventDispatcher.dispatch(ex);
             }
         }
+        return -1;
     }
 
     private int post(HttpUrl url, Object o) {

src/main/java/io/getunleash/metric/UnleashMetricServiceImpl.java

@@ -1,12 +1,16 @@
 package io.getunleash.metric;
 
+import io.getunleash.util.Throttler;
 import io.getunleash.util.UnleashConfig;
 import io.getunleash.util.UnleashScheduledExecutor;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.util.Set;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class UnleashMetricServiceImpl implements UnleashMetricService {
+    private static final Logger LOGGER = LoggerFactory.getLogger(UnleashMetricServiceImpl.class);
     private final LocalDateTime started;
     private final UnleashConfig unleashConfig;
 
@@ -15,6 +19,8 @@ public class UnleashMetricServiceImpl implements UnleashMetricService {
     // mutable
     private volatile MetricsBucket currentMetricsBucket;
 
+    private final Throttler throttler;
+
     public UnleashMetricServiceImpl(
             UnleashConfig unleashConfig, UnleashScheduledExecutor executor) {
         this(unleashConfig, unleashConfig.getMetricSenderFactory().apply(unleashConfig), executor);
@@ -28,6 +34,11 @@ public UnleashMetricServiceImpl(
         this.started = LocalDateTime.now(ZoneId.of("UTC"));
         this.unleashConfig = unleashConfig;
         this.metricSender = metricSender;
+        this.throttler =
+                new Throttler(
+                        (int) unleashConfig.getSendMetricsInterval(),
+                        300,
+                        unleashConfig.getUnleashURLs().getClientMetricsURL());
         long metricsInterval = unleashConfig.getSendMetricsInterval();
         executor.setInterval(sendMetrics(), metricsInterval, metricsInterval);
     }
@@ -51,11 +62,29 @@ public void countVariant(String toggleName, String variantName) {
 
     private Runnable sendMetrics() {
         return () -> {
-            MetricsBucket metricsBucket = this.currentMetricsBucket;
-            this.currentMetricsBucket = new MetricsBucket();
-            metricsBucket.end();
-            ClientMetrics metrics = new ClientMetrics(unleashConfig, metricsBucket);
-            metricSender.sendMetrics(metrics);
+            if (throttler.performAction()) {
+                MetricsBucket metricsBucket = this.currentMetricsBucket;
+                this.currentMetricsBucket = new MetricsBucket();
+                metricsBucket.end();
+                ClientMetrics metrics = new ClientMetrics(unleashConfig, metricsBucket);
+                int statusCode = metricSender.sendMetrics(metrics);
+                if (statusCode >= 200 && statusCode < 400) {
+                    throttler.decrementFailureCountAndResetSkips();
+                }
+                if (statusCode >= 400) {
+                    throttler.handleHttpErrorCodes(statusCode);
+                }
+            } else {
+                throttler.skipped();
+            }
         };
     }
+
+    protected int getSkips() {
+        return this.throttler.getSkips();
+    }
+
+    protected int getFailures() {
+        return this.throttler.getFailures();
+    }
 }

src/main/java/io/getunleash/repository/FeatureRepository.java

@@ -6,21 +6,26 @@
 import io.getunleash.event.EventDispatcher;
 import io.getunleash.event.UnleashReady;
 import io.getunleash.lang.Nullable;
+import io.getunleash.util.Throttler;
 import io.getunleash.util.UnleashConfig;
 import io.getunleash.util.UnleashScheduledExecutor;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class FeatureRepository implements IFeatureRepository {
-
+    private static final Logger LOGGER = LoggerFactory.getLogger(FeatureRepository.class);
     private final UnleashConfig unleashConfig;
     private final BackupHandler<FeatureCollection> featureBackupHandler;
     private final FeatureBootstrapHandler featureBootstrapHandler;
     private final FeatureFetcher featureFetcher;
     private final EventDispatcher eventDispatcher;
 
+    private final Throttler throttler;
+
     private FeatureCollection featureCollection;
     private boolean ready;
 
@@ -36,7 +41,11 @@ public FeatureRepository(
         this.featureFetcher = unleashConfig.getUnleashFeatureFetcherFactory().apply(unleashConfig);
         this.featureBootstrapHandler = new FeatureBootstrapHandler(unleashConfig);
         this.eventDispatcher = new EventDispatcher(unleashConfig);
-
+        this.throttler =
+                new Throttler(
+                        (int) unleashConfig.getFetchTogglesInterval(),
+                        300,
+                        unleashConfig.getUnleashURLs().getFetchTogglesURL());
         this.initCollections(unleashConfig.getScheduledExecutor());
     }
 
@@ -46,12 +55,16 @@ protected FeatureRepository(
             EventDispatcher eventDispatcher,
             FeatureFetcher featureFetcher,
             FeatureBootstrapHandler featureBootstrapHandler) {
-
         this.unleashConfig = unleashConfig;
         this.featureBackupHandler = featureBackupHandler;
         this.featureFetcher = featureFetcher;
         this.featureBootstrapHandler = featureBootstrapHandler;
         this.eventDispatcher = eventDispatcher;
+        this.throttler =
+                new Throttler(
+                        (int) unleashConfig.getFetchTogglesInterval(),
+                        300,
+                        unleashConfig.getUnleashURLs().getFetchTogglesURL());
         this.initCollections(unleashConfig.getScheduledExecutor());
     }
 
@@ -66,6 +79,11 @@ protected FeatureRepository(
         this.featureFetcher = featureFetcher;
         this.featureBootstrapHandler = featureBootstrapHandler;
         this.eventDispatcher = new EventDispatcher(unleashConfig);
+        this.throttler =
+                new Throttler(
+                        (int) unleashConfig.getFetchTogglesInterval(),
+                        300,
+                        unleashConfig.getUnleashURLs().getFetchTogglesURL());
         this.initCollections(executor);
     }
 
@@ -90,33 +108,44 @@ private void initCollections(UnleashScheduledExecutor executor) {
         }
     }
 
+    private Integer calculateMaxSkips(int fetchTogglesInterval) {
+        return Integer.max(20, 300 / Integer.max(fetchTogglesInterval, 1));
+    }
+
     private Runnable updateFeatures(@Nullable final Consumer<UnleashException> handler) {
         return () -> {
-            try {
-                ClientFeaturesResponse response = featureFetcher.fetchFeatures();
-                eventDispatcher.dispatch(response);
-                if (response.getStatus() == ClientFeaturesResponse.Status.CHANGED) {
-                    SegmentCollection segmentCollection = response.getSegmentCollection();
-                    featureCollection =
-                            new FeatureCollection(
-                                    response.getToggleCollection(),
-                                    segmentCollection != null
-                                            ? segmentCollection
-                                            : new SegmentCollection(Collections.emptyList()));
-
-                    featureBackupHandler.write(featureCollection);
-                }
-
-                if (!ready) {
-                    eventDispatcher.dispatch(new UnleashReady());
-                    ready = true;
-                }
-            } catch (UnleashException e) {
-                if (handler != null) {
-                    handler.accept(e);
-                } else {
-                    throw e;
+            if (throttler.performAction()) {
+                try {
+                    ClientFeaturesResponse response = featureFetcher.fetchFeatures();
+                    eventDispatcher.dispatch(response);
+                    if (response.getStatus() == ClientFeaturesResponse.Status.CHANGED) {
+                        SegmentCollection segmentCollection = response.getSegmentCollection();
+                        featureCollection =
+                                new FeatureCollection(
+                                        response.getToggleCollection(),
+                                        segmentCollection != null
+                                                ? segmentCollection
+                                                : new SegmentCollection(Collections.emptyList()));
+
+                        featureBackupHandler.write(featureCollection);
+                    } else if (response.getStatus() == ClientFeaturesResponse.Status.UNAVAILABLE) {
+                        throttler.handleHttpErrorCodes(response.getHttpStatusCode());
+                        return;
+                    }
+                    throttler.decrementFailureCountAndResetSkips();
+                    if (!ready) {
+                        eventDispatcher.dispatch(new UnleashReady());
+                        ready = true;
+                    }
+                } catch (UnleashException e) {
+                    if (handler != null) {
+                        handler.accept(e);
+                    } else {
+                        throw e;
+                    }
                 }
+            } else {
+                throttler.skipped(); // We didn't do anything this iteration, just reduce the count
             }
         };
     }
@@ -137,4 +166,12 @@ public List<String> getFeatureNames() {
     public Segment getSegment(Integer id) {
         return featureCollection.getSegmentCollection().getSegment(id);
     }
+
+    public Integer getFailures() {
+        return this.throttler.getFailures();
+    }
+
+    public Integer getSkips() {
+        return this.throttler.getSkips();
+    }
 }

src/main/java/io/getunleash/repository/FeatureToggleResponse.java

@@ -13,7 +13,7 @@ public class FeatureToggleResponse implements UnleashEvent {
     public enum Status {
         NOT_CHANGED,
         CHANGED,
-        UNAVAILABLE
+        UNAVAILABLE,
     }
 
     private final Status status;

src/main/java/io/getunleash/util/ConstraintMerger.java

@@ -17,7 +17,8 @@ public static List<Constraint> mergeConstraints(
                         Optional.ofNullable(strategy.getConstraints())
                                 .orElseGet(Collections::emptyList),
                         Optional.ofNullable(strategy.getSegments())
-                                .orElseGet(Collections::emptyList).stream()
+                                .orElseGet(Collections::emptyList)
+                                .stream()
                                 .map(repository::getSegment)
                                 .map(s -> s == null ? DENY_SEGMENT : s)
                                 .map(Segment::getConstraints)