FFM-11022 Flag/Group cache recovery

client/api/Config.cs

@@ -22,10 +22,13 @@ public class Config
         internal bool streamEnabled = true;
         internal int evaluationMetricsMaxSize = 10000;
         internal int targetMetricsMaxSize = 100000;
+        internal int cacheRecoveryTimeoutInMs = 5000; 
+
+
 
         public Config(string configUrl, string eventUrl, bool streamEnabled, int pollIntervalInSeconds,
             bool analyticsEnabled, int frequency, int targetMetricsMaxSize, int connectionTimeout, int readTimeout,
-            int writeTimeout, bool debug, long metricsServiceAcceptableDuration)
+            int writeTimeout, bool debug, long metricsServiceAcceptableDuration, int cacheRecoveryTimeoutInMs)
         {
             this.configUrl = configUrl;
             this.eventUrl = eventUrl;
@@ -39,6 +42,7 @@ public class Config
             this.writeTimeout = writeTimeout;
             this.debug = debug;
             this.metricsServiceAcceptableDuration = metricsServiceAcceptableDuration;
+            this.cacheRecoveryTimeoutInMs = cacheRecoveryTimeoutInMs;
         }
 
         public Config()
@@ -64,6 +68,7 @@ public Config()
 
         public int TargetMetricsMaxSize => targetMetricsMaxSize;
         public int EvaluationMetricsMaxSize => evaluationMetricsMaxSize;
+        public int CacheRecoveryTimeoutInMs => cacheRecoveryTimeoutInMs;
 
 
         /**
@@ -189,6 +194,12 @@ public ConfigBuilder debug(bool debug)
             configtobuild.debug = debug;
             return this;
         }
+
+        public ConfigBuilder SetCacheRecoveryTimeout(int timeoutMilliseconds)
+        {
+            configtobuild.cacheRecoveryTimeoutInMs = timeoutMilliseconds;
+            return this;
+        }
 
         /// <summary>
         /// <para>

client/api/Evaluator.cs

@@ -33,15 +33,20 @@ internal class Evaluator : IEvaluator
         private readonly ILogger<Evaluator> logger;
         private readonly ILoggerFactory loggerFactory;
         private readonly IRepository repository;
+        private readonly IPollingProcessor poller;
+        private readonly Config config;
+
 
         public Evaluator(IRepository repository, IEvaluatorCallback callback, ILoggerFactory loggerFactory,
-            bool isAnalyticsEnabled)
+            bool isAnalyticsEnabled, IPollingProcessor poller, Config config)
         {
             this.repository = repository;
             this.callback = callback;
             logger = loggerFactory.CreateLogger<Evaluator>();
             this.loggerFactory = loggerFactory;
             IsAnalyticsEnabled = isAnalyticsEnabled;
+            this.poller = poller;
+            this.config = config;
         }
 
         public bool BoolVariation(string key, Target target, bool defaultValue)
@@ -85,8 +90,36 @@ public string StringVariation(string key, Target target, string defaultValue)
         private Variation EvaluateVariation(string key, Target target, FeatureConfigKind kind)
         {
             var featureConfig = repository.GetFlag(key);
-            if (featureConfig == null || featureConfig.Kind != kind)
+            if (featureConfig == null)
+            {
+                logger.LogWarning(
+                    "Unable to find flag {Key} in cache, refreshing flag cache and retrying evaluation ",
+                    key);
+                var refreshResult = poller.RefreshFlags(TimeSpan.FromSeconds(config.CacheRecoveryTimeoutInMs));
+
+                if (refreshResult != RefreshOutcome.Success)
+                    return null;
+
+                // Re-attempt to fetch the feature config after the refresh
+                featureConfig = repository.GetFlag(key);
+
+                // If still not found or doesn't match the kind, return null to indicate failure
+                if (featureConfig == null)
+                {
+                    logger.LogError(
+                        "Failed to find flag {Key} in cache even after attempting a refresh. Check flag exists in project",
+                        key);
+                    return null;
+                }
+            }
+
+            if (featureConfig.Kind != kind)
+            {
+                logger.LogWarning(
+                    "Requested variation {Kind} does not match flag {Key} which is of type {featureConfigKind}",
+                    kind,  key, featureConfig.Kind);
                 return null;
+            }
 
             var prerequisites = featureConfig.Prerequisites;
             if (prerequisites != null && prerequisites.Count > 0)

client/api/InnerClient.cs

@@ -33,6 +33,7 @@ internal class InnerClient :
         private IEvaluator evaluator;
         private MetricsProcessor metric;
         private IConnector connector;
+        private Config config;
 
         public event EventHandler InitializationCompleted;
         public event EventHandler<string> EvaluationChanged;
@@ -50,6 +51,7 @@ public InnerClient(string apiKey, Config config, CfClient parent, ILoggerFactory
             this.loggerFactory = loggerFactory;
             this.parent = parent;
             this.logger = loggerFactory.CreateLogger<InnerClient>();
+            this.config = config;
             Initialize(apiKey, config);
         }
 
@@ -81,7 +83,7 @@ public void Initialize(IConnector connector, Config config)
             this.repository = new StorageRepository(config.Cache, config.Store, this, loggerFactory);
             this.polling = new PollingProcessor(connector, this.repository, config, this, loggerFactory);
             this.update = new UpdateProcessor(connector, this.repository, config, this, loggerFactory);
-            this.evaluator = new Evaluator(this.repository, this, loggerFactory, config.analyticsEnabled);
+            this.evaluator = new Evaluator(this.repository, this, loggerFactory, config.analyticsEnabled, polling, config);
             // Since 1.4.2, we enable the global target for evaluation metrics. 
             this.metric = new MetricsProcessor(config, evaluationAnalyticsCache, targetAnalyticsCache, new AnalyticsPublisherService(connector, evaluationAnalyticsCache, targetAnalyticsCache, loggerFactory), loggerFactory, true);
             Start();
@@ -213,38 +215,82 @@ private void OnNotifyEvaluationChanged(string identifier)
             EvaluationChanged?.Invoke(parent, identifier);
         }
 
-        public bool BoolVariation(string key, dto.Target target, bool defaultValue)
+        public bool BoolVariation(string key, Target target, bool defaultValue)
         {
             try
             {
                 return evaluator.BoolVariation(key, target, defaultValue);
             }
             catch (InvalidCacheStateException ex)
             {
-                logger.LogError(ex, "Invalid cache state detected when evaluating boolean variation for flag {Key}",
+                logger.LogWarning(ex,
+                    "Invalid cache state detected when evaluating boolean variation for flag {Key}, refreshing cache and retrying evaluation ",
                     key);
-                LogEvaluationFailureError(FeatureConfigKind.Boolean, key, target, defaultValue.ToString());
-                polling.TriggerProcessSegments();
-                return defaultValue;
+                // Attempt to refresh cache
+                var result = polling.RefreshFlagsAndSegments(TimeSpan.FromMilliseconds(2000));
+
+                // If the refresh has failed or exceeded the timout, return default variation
+                if (result != RefreshOutcome.Success)
+                {
+                    logger.LogError(ex,
+                        "Refreshing cache for boolean variation for flag {Key} failed, returning default variation ",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Boolean, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
+
+                try
+                {
+                    return evaluator.BoolVariation(key, target, defaultValue);
+                }
+                catch (InvalidCacheStateException)
+                {
+                    logger.LogError(ex,
+                        "Attempted re-evaluation of boolean variation for flag {Key} after refreshing cache failed due to invalid cache state, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Boolean, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
             }
         }
 
-        public string StringVariation(string key, dto.Target target, string defaultValue)
+        public string StringVariation(string key, Target target, string defaultValue)
         {
             try
             {
                 return evaluator.StringVariation(key, target, defaultValue);
             }
             catch (InvalidCacheStateException ex)
             {
-                logger.LogError(ex, "Invalid cache state detected when evaluating string variation for flag {Key}",
+                logger.LogWarning(ex,
+                    "Invalid cache state detected when evaluating string variation for flag {Key}, refreshing cache and retrying evaluation",
                     key);
-                LogEvaluationFailureError(FeatureConfigKind.String, key, target, defaultValue);
-                polling.TriggerProcessSegments();
-                return defaultValue;
+                var result = polling.RefreshFlagsAndSegments(TimeSpan.FromSeconds(config.CacheRecoveryTimeoutInMs));
+                if (result != RefreshOutcome.Success)
+                {
+                    logger.LogError(
+                        "Refreshing cache for string variation for flag {Key} failed, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.String, key, target, defaultValue);
+                    return defaultValue;
+                }
+
+                try
+                {
+                    return evaluator.StringVariation(key, target, defaultValue);
+                }
+                catch (InvalidCacheStateException)
+                {
+                    logger.LogWarning(
+                        "Attempted re-evaluation of string variation for flag {Key} after refreshing cache failed due to invalid cache state, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.String, key, target, defaultValue);
+                    return defaultValue;
+                }
             }
         }
 
+
         public double NumberVariation(string key, Target target, double defaultValue)
         {
             try
@@ -253,14 +299,35 @@ public double NumberVariation(string key, Target target, double defaultValue)
             }
             catch (InvalidCacheStateException ex)
             {
-                logger.LogError(ex, "Invalid cache state detected when evaluating number variation for flag {Key}",
+                logger.LogWarning(ex,
+                    "Invalid cache state detected when evaluating number variation for flag {Key}, refreshing cache and retrying evaluation",
                     key);
-                LogEvaluationFailureError(FeatureConfigKind.Int, key, target, defaultValue.ToString());
-                polling.TriggerProcessSegments();
-                return defaultValue;
+                var result = polling.RefreshFlagsAndSegments(TimeSpan.FromSeconds(config.CacheRecoveryTimeoutInMs));
+                if (result != RefreshOutcome.Success)
+                {
+                    logger.LogError(
+                        "Refreshing cache for number variation for flag {Key} failed, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Int, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
+
+                try
+                {
+                    return evaluator.NumberVariation(key, target, defaultValue);
+                }
+                catch (InvalidCacheStateException)
+                {
+                    logger.LogWarning(
+                        "Attempted re-evaluation of number variation for flag {Key} after refreshing cache failed due to invalid cache state, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Int, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
             }
         }
 
+
         public JObject JsonVariation(string key, Target target, JObject defaultValue)
         {
             try
@@ -269,14 +336,35 @@ public JObject JsonVariation(string key, Target target, JObject defaultValue)
             }
             catch (InvalidCacheStateException ex)
             {
-                logger.LogError(ex, "Invalid cache state detected when evaluating json variation for flag {Key}",
+                logger.LogWarning(ex,
+                    "Invalid cache state detected when evaluating json variation for flag {Key}, refreshing cache and retrying evaluation",
                     key);
-                LogEvaluationFailureError(FeatureConfigKind.Json, key, target, defaultValue.ToString());
-                polling.TriggerProcessSegments();
-                return defaultValue;
+                var result = polling.RefreshFlagsAndSegments(TimeSpan.FromSeconds(config.CacheRecoveryTimeoutInMs));
+                if (result != RefreshOutcome.Success)
+                {
+                    logger.LogError(
+                        "Refreshing cache for json variation for flag {Key} failed, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Json, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
+
+                try
+                {
+                    return evaluator.JsonVariation(key, target, defaultValue);
+                }
+                catch (InvalidCacheStateException)
+                {
+                    logger.LogWarning(
+                        "Attempted re-evaluation of json variation for flag {Key} after refreshing cache failed due to invalid cache state, returning default variation",
+                        key);
+                    LogEvaluationFailureError(FeatureConfigKind.Json, key, target, defaultValue.ToString());
+                    return defaultValue;
+                }
             }
         }
 
+
         public void Close()
         {
             this.connector?.Close();