Adding the email rollout strategy to feature flag (#6541)

This PR adds the email based rollout strategy to features. We can now define a list of domain names in the init-flags.yml file and define the domains for which the feature will be active.

Also added tests to assert the functionality for this flag flipping strategy.

app/server/appsmith-server/src/main/java/com/appsmith/server/featureflags/FeatureFlagEnum.java

@@ -20,6 +20,7 @@ public enum FeatureFlagEnum {
     // ------------------- Couldn't find a better way to do this ---------------------------------------------------- //
     TEST_FEATURE_1,
     TEST_FEATURE_2,
+    TEST_FEATURE_3,
     // ------------------- End of features for testing -------------------------------------------------------------- //
 
     // ------------------- These are actual feature flags meant to be used across the product ----------------------- //

app/server/appsmith-server/src/main/java/com/appsmith/server/featureflags/strategies/EmailBasedRolloutStrategy.java

@@ -0,0 +1,48 @@
+package com.appsmith.server.featureflags.strategies;
+
+import com.appsmith.server.constants.FieldName;
+import com.appsmith.server.domains.User;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
+import org.ff4j.core.FeatureStore;
+import org.ff4j.core.FlippingExecutionContext;
+import org.ff4j.strategy.AbstractFlipStrategy;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+@Slf4j
+public class EmailBasedRolloutStrategy extends AbstractFlipStrategy {
+
+    List<String> validDomains = new ArrayList<>();
+
+    private static final String PARAM_EMAIL_DOMAINS = "emailDomains";
+
+    /** {@inheritDoc} */
+    @Override
+    public void init(String featureName, Map<String, String> initParam) {
+        super.init(featureName, initParam);
+        assertRequiredParameter(PARAM_EMAIL_DOMAINS);
+        if (!StringUtils.isEmpty(initParam.get(PARAM_EMAIL_DOMAINS))) {
+            this.validDomains = Arrays.asList(initParam.get(PARAM_EMAIL_DOMAINS).split(","));
+        }
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public boolean evaluate(String featureName, FeatureStore store, FlippingExecutionContext executionContext) {
+        User user = (User) executionContext.getValue(FieldName.USER, true);
+        log.debug("Checking if feature {} is active for user {}", featureName, user.getEmail());
+        int atIndex = user.getEmail().indexOf("@");
+
+        if (atIndex > 0) {
+            // If the email domain is valid, check the user's email ID against the list of validated domains
+            String domain = user.getEmail().substring(atIndex + 1).toLowerCase();
+            return validDomains.contains(domain);
+        }
+        return false;
+
+    }
+}

app/server/appsmith-server/src/main/resources/features/init-flags.yml

@@ -22,7 +22,7 @@ ff4j:
       enable: true
       description: Enable this feature based on email ID of the user
       flipstrategy:
-        class: com.appsmith.server.featureflags.strategies.AppsmithUserStrategy
+        class: com.appsmith.server.featureflags.strategies.EmailBasedRolloutStrategy
         param:
-          - name: requiredKey
-            value: requiredValue
+          - name: emailDomains
+            value: appsmith.com,wazirx.com,pharmeasy.in,allround.club

app/server/appsmith-server/src/test/java/com/appsmith/server/featureflags/strategies/EmailBasedRolloutStrategyTest.java

@@ -0,0 +1,60 @@
+package com.appsmith.server.featureflags.strategies;
+
+import com.appsmith.server.domains.User;
+import lombok.extern.slf4j.Slf4j;
+import org.ff4j.core.FlippingExecutionContext;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.security.test.context.support.WithUserDetails;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@Slf4j
+public class EmailBasedRolloutStrategyTest {
+
+    EmailBasedRolloutStrategy strategy = new EmailBasedRolloutStrategy();
+
+    @Before
+    @WithUserDetails(value = "api_user")
+    public void setup() {
+        Map<String, String> initParams = new HashMap<>();
+        initParams.put("emailDomains", "example.com,another-example.com");
+        strategy.init("test-feature", initParams);
+    }
+
+    @Test
+    @WithUserDetails(value = "api_user")
+    public void testValidFeatureCheck() {
+        FlippingExecutionContext executionContext = Mockito.mock(FlippingExecutionContext.class);
+
+        User user = new User();
+        user.setEmail("test@EXAMPLE.com");
+        Mockito.when(executionContext.getValue(Mockito.anyString(), Mockito.anyBoolean())).thenReturn(user);
+
+        boolean evaluate = strategy.evaluate("test-feature", null, executionContext);
+        assertTrue(evaluate);
+    }
+
+    @Test
+    @WithUserDetails(value = "api_user")
+    public void testInvalidFeatureCheck() {
+        FlippingExecutionContext executionContext = Mockito.mock(FlippingExecutionContext.class);
+
+        User user = new User();
+        user.setEmail("test@random.com");
+        Mockito.when(executionContext.getValue(Mockito.anyString(), Mockito.anyBoolean())).thenReturn(user);
+
+        boolean evaluate = strategy.evaluate("test-feature", null, executionContext);
+        assertFalse(evaluate);
+    }
+}

app/server/appsmith-server/src/test/java/com/appsmith/server/services/FeatureFlagServiceTest.java

@@ -85,4 +85,18 @@ public class FeatureFlagServiceTest {
                 .verifyComplete();
     }
 
+    @Test
+    @WithUserDetails(value = "api_user")
+    public void testFeatureCheckForEmailStrategy() {
+        StepVerifier.create(featureFlagService.getAllFeatureFlagsForUser())
+                .assertNext(result -> {
+                    assertNotNull(result);
+                    assertTrue("There should be a flag TEST_FEATURE_3",
+                            result.keySet().contains(FeatureFlagEnum.TEST_FEATURE_3.toString())
+                    );
+                    assertFalse(result.get(FeatureFlagEnum.TEST_FEATURE_3.toString()));
+                })
+                .verifyComplete();
+    }
+
 }

app/server/appsmith-server/src/test/resources/features/init-flags-test.yml

@@ -25,4 +25,13 @@ ff4j:
         class: org.ff4j.strategy.PonderationStrategy
         param:
           - name: weight
-            value: 1
+            value: 1
+
+    - uid: TEST_FEATURE_3
+      enable: true
+      description: The test feature should only be visible to certain  users
+      flipstrategy:
+        class: com.appsmith.server.featureflags.strategies.EmailBasedRolloutStrategy
+        param:
+          - name: emailDomains
+            value: test@example.com