feat: Statsig provider evaluate boolean updates (#691)

Signed-off-by: liran2000 <liran2000@gmail.com>

providers/statsig/README.md

@@ -18,10 +18,11 @@
 <!-- x-release-please-end-version -->
 
 ## Concepts
-* Boolean evaluation gets [gate](https://docs.statsig.com/server/javaSdk#checking-a-gate) status.
 * String/Integer/Double evaluations evaluation gets [Dynamic config](https://docs.statsig.com/server/javaSdk#reading-a-dynamic-config) or [Layer](https://docs.statsig.com/server/javaSdk#getting-an-layerexperiment) evaluation.
   As the key represents an inner attribute, feature config is required as a parameter with data needed for evaluation.
   For an example of dynamic config of product alias, need to differentiate between dynamic config or layer, and the dynamic config name.
+* Boolean evaluation gets [gate](https://docs.statsig.com/server/javaSdk#checking-a-gate) status when feature config is not passed.
+  When feature config exists, it evaluates to the config/layer attribute, similar to String/Integer/Float evaluations.
 * Object evaluation gets a structure representing the dynamic config or layer.
 * [Private Attributes](https://docs.statsig.com/server/javaSdk#private-attributes) are supported as 'privateAttributes' context key.
 
@@ -71,3 +72,8 @@ Unit test based on Statsig [Local Overrides](https://docs.statsig.com/server/jav
 As it is limited, evaluation context based tests are limited.
 See [statsigProviderTest](./src/test/java/dev/openfeature/contrib/providers/statsig/StatsigProviderTest.java)
 for more information.
+
+## Known issues
+- Gate BooleanEvaluation with default value true cannot fallback to true.
+  https://github.com/statsig-io/java-server-sdk/issues/22
+

providers/statsig/src/main/java/dev/openfeature/contrib/providers/statsig/StatsigProvider.java

@@ -85,8 +85,27 @@ public Metadata getMetadata() {
     public ProviderEvaluation<Boolean> getBooleanEvaluation(String key, Boolean defaultValue, EvaluationContext ctx) {
         verifyEvaluation();
         StatsigUser user = ContextTransformer.transform(ctx);
-        Future<Boolean> featureOn = Statsig.checkGateAsync(user, key);
-        Boolean evaluatedValue = featureOn.get();
+        Boolean evaluatedValue = defaultValue;
+        try {
+            FeatureConfig featureConfig = parseFeatureConfig(ctx);
+            switch (featureConfig.getType()) {
+                case CONFIG:
+                    DynamicConfig dynamicConfig = fetchDynamicConfig(user, featureConfig);
+                    evaluatedValue = dynamicConfig.getBoolean(key, defaultValue);
+                    break;
+                case LAYER:
+                    Layer layer = fetchLayer(user, featureConfig);
+                    evaluatedValue = layer.getBoolean(key, defaultValue);
+                    break;
+                default:
+                    break;
+            }
+        } catch (Exception e) {
+            log.debug("could not fetch feature config. checking gate {}.", key);
+            Future<Boolean> featureOn = Statsig.checkGateAsync(user, key);
+            evaluatedValue = featureOn.get();
+        }
+
         return ProviderEvaluation.<Boolean>builder()
             .value(evaluatedValue)
             .build();

providers/statsig/src/test/java/dev/openfeature/contrib/providers/statsig/StatsigProviderTest.java

@@ -75,6 +75,7 @@ static void setUp() {
     private static void buildFlags() {
         Statsig.overrideGate(FLAG_NAME, true);
         Map<String, Object> configMap = new HashMap<>();
+        configMap.put("boolean", true);
         configMap.put("alias", "test");
         configMap.put("revision", INT_FLAG_VALUE);
         configMap.put("price", DOUBLE_FLAG_VALUE);
@@ -118,6 +119,17 @@ void getBooleanEvaluation() {
         assertEquals(true, client.getBooleanValue(FLAG_NAME, false));
         assertEquals(false, statsigProvider.getBooleanEvaluation("non-existing", false, new ImmutableContext()).getValue());
         assertEquals(false, client.getBooleanValue("non-existing", false));
+
+        // expected to succeed when https://github.com/statsig-io/java-server-sdk/issues/22 is resolved and adopted
+//        assertEquals(true, client.getBooleanValue("non-existing", true));
+
+        MutableContext evaluationContext = new MutableContext();
+        MutableContext featureConfig = new MutableContext();
+        featureConfig.add("type", "CONFIG");
+        featureConfig.add("name", "product");
+        evaluationContext.add("feature_config", featureConfig);
+        assertEquals(true, statsigProvider.getBooleanEvaluation("boolean", false,
+            evaluationContext).getValue());
     }
 
     @Test