Added feature flags logic (whitelist, blacklist and rollout percentage included)

README.md

@@ -172,3 +172,74 @@ For additional details, please refer to the blog post [Hello DCO, Goodbye CLA: S
 ## License
 
 The Spring PetClinic sample application is released under version 2.0 of the [Apache License](https://www.apache.org/licenses/LICENSE-2.0).
+
+# PetClinic Feature Flags
+- This project adds feature flags to the PetClinic app so that we can control the features to certain users.
+
+# How it works:
+- Enable/Disable:
+    Each feature can be enabled/disabled for the users based on if they are whitelisted or blacklisted. There is also a global disability which shuts down the specified feature until enabled.
+- Whitelist:
+    Only users listed in the whitelist can access the feature specified.
+- Blacklist:
+    Users listed in the blacklist will be blocked from the feature even if the feature is enabled.
+- Rollout Percentage:
+    You can release a feature gradually instead of a global release. For example, if rollout_percentage = 50, roughly 50% of users get access (deterministic by user ID).
+
+# Example:
+    | Feature Key  | Enabled | Blacklist | Whitelist | Rollout % |
+    | ------------ | ------- | --------- | --------- | --------- |
+    | ADD_PET      | true    | 4         | 1         | 100       |
+    | OWNER_SEARCH | true    | -         | -         | 50        |
+
+    Owner with id 4 is blacklisted i.e. they cannot add pets.
+    Owner with id 1 is whiteliste i.e. they can addpets.
+    The rollout percentage of OWNER_SEARCH key is 50% i.e. roughly half the users can search for owners.
+
+# Using Feature Flags in Code:
+    @FeatureFlagEnabled("ADD_PET")
+    @GetMapping("/owners/{ownerId}/pets/new")
+    public String newPetForm(@PathVariable int ownerId) {
+        return "pets/createPetForm";
+    }
+
+    The Aspect intercepts the method and checks if the feature i.e. ADD_PET is:
+    1. Enabled
+    2. If user is whitelisted/blacklisted
+    3. Rollout percentage
+    If access is denied, the user gets HTTP 403 Forbidden.
+
+# Database Setup:
+- Tables
+    CREATE TABLE feature_flags (
+        id INT AUTO_INCREMENT PRIMARY KEY,
+        flag_key VARCHAR(100) UNIQUE,
+        is_enabled BOOLEAN,
+        globally_disabled BOOLEAN,
+        description VARCHAR(255),
+        rollout_percentage INT
+    );
+
+    CREATE TABLE feature_flag_blacklist (
+        feature_flag_id INT,
+        owner_id INT
+    );
+
+    CREATE TABLE feature_flag_whitelist (
+        feature_flag_id INT,
+        owner_id INT
+    );
+
+- Example Data
+    INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description, rollout_percentage)
+    VALUES ('ADD_PET', true, false, 'Allows adding pets', 100);
+
+    INSERT INTO feature_flag_blacklist (feature_flag_id, owner_id) VALUES (1, 4);
+    INSERT INTO feature_flag_whitelist (feature_flag_id, owner_id) VALUES (1, 1);
+
+# Why Feature Flags?
+- Roll out features gradually.
+- Access control i.e. privilege to users.
+- Feature blocking whenever needed i.e. internal errors or data corruption.
+- Avoid frequent code redeployment for feature changes. 
+

src/main/java/org/springframework/samples/petclinic/model/FeatureFlag.java

@@ -0,0 +1,135 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.samples.petclinic.model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import jakarta.persistence.CollectionTable;
+import jakarta.persistence.Column;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.Table;
+import jakarta.validation.constraints.NotBlank;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+@Entity
+@Table(name = "feature_flags")
+public class FeatureFlag extends BaseEntity {
+
+	@Column(name = "flag_key", unique = true)
+	@NotBlank
+	private String key;
+
+	@Column(name = "is_enabled")
+	private boolean isEnabled;
+
+	@Column(name = "globally_disabled")
+	private boolean globallyDisabled;
+
+	@Column(name = "rollout_percentage")
+	private Integer rolloutPercentage;
+
+	@Column(name = "description")
+	private String description;
+
+	@ElementCollection(fetch = FetchType.EAGER)
+	@CollectionTable(name = "feature_flag_blacklist", joinColumns = @JoinColumn(name = "feature_flag_id"))
+	@JsonIgnore
+	@Column(name = "owner_id")
+	private List<Integer> blacklistedUsers = new ArrayList<>();
+
+	@ElementCollection(fetch = FetchType.EAGER)
+	@CollectionTable(name = "feature_flag_whitelist", joinColumns = @JoinColumn(name = "feature_flag_id"))
+	@JsonIgnore
+	@Column(name = "owner_id")
+	private List<Integer> whitelistedUsers = new ArrayList<>();
+
+	public boolean isAllowedForOwner(Integer ownerId) {
+		if (globallyDisabled) {
+			return false;
+		}
+
+		if (ownerId != null && blacklistedUsers.contains(ownerId)) {
+			return false;
+		}
+
+		if (ownerId != null && whitelistedUsers.contains(ownerId)) {
+			return true;
+		}
+
+		if (rolloutPercentage != null && ownerId != null) {
+			int bucket = Math.abs(ownerId.hashCode() % 100);
+			return bucket < rolloutPercentage;
+		}
+		return isEnabled;
+	}
+
+	public String getKey() {
+		return key;
+	}
+
+	public void setKey(String key) {
+		this.key = key;
+	}
+
+	public boolean isEnabled() {
+		return isEnabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.isEnabled = enabled;
+	}
+
+	public boolean isGloballyDisabled() {
+		return globallyDisabled;
+	}
+
+	public void setGloballyDisabled(boolean globallyDisabled) {
+		this.globallyDisabled = globallyDisabled;
+	}
+
+	public String getDescription() {
+		return description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	@JsonIgnore
+	public List<Integer> getBlacklistedUsers() {
+		return blacklistedUsers;
+	}
+
+	public void setBlacklistedUsers(List<Integer> blacklistedUsers) {
+		this.blacklistedUsers = blacklistedUsers;
+	}
+
+	@JsonIgnore
+	public List<Integer> getWhitelistedUsers() {
+		return whitelistedUsers;
+	}
+
+	public void setWhitelistedUsers(List<Integer> whitelistedUsers) {
+		this.whitelistedUsers = whitelistedUsers;
+	}
+
+}

src/main/java/org/springframework/samples/petclinic/owner/OwnerController.java

@@ -20,6 +20,7 @@ import java.util.Objects;
 import java.util.Optional;
 
 import org.springframework.data.domain.Page;
+import org.springframework.samples.petclinic.system.FeatureFlagEnabled;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Controller;
@@ -69,11 +70,13 @@ class OwnerController {
 							+ ". Please ensure the ID is correct " + "and the owner exists in the database."));
 	}
 
+	@FeatureFlagEnabled("OWNER_ADD")
 	@GetMapping("/owners/new")
 	public String initCreationForm() {
 		return VIEWS_OWNER_CREATE_OR_UPDATE_FORM;
 	}
 
+	@FeatureFlagEnabled("OWNER_ADD")
 	@PostMapping("/owners/new")
 	public String processCreationForm(@Valid Owner owner, BindingResult result, RedirectAttributes redirectAttributes) {
 		if (result.hasErrors()) {
@@ -92,6 +95,7 @@ class OwnerController {
 	}
 
 	@GetMapping("/owners")
+	@FeatureFlagEnabled("OWNER_SEARCH")
 	public String processFindForm(@RequestParam(defaultValue = "1") int page, Owner owner, BindingResult result,
 			Model model) {
 		// allow parameterless GET request for /owners to return all records
@@ -133,11 +137,13 @@ class OwnerController {
 		return owners.findByLastNameStartingWith(lastname, pageable);
 	}
 
+	@FeatureFlagEnabled("OWNER_EDIT")
 	@GetMapping("/owners/{ownerId}/edit")
 	public String initUpdateOwnerForm() {
 		return VIEWS_OWNER_CREATE_OR_UPDATE_FORM;
 	}
 
+	@FeatureFlagEnabled("OWNER_EDIT")
 	@PostMapping("/owners/{ownerId}/edit")
 	public String processUpdateOwnerForm(@Valid Owner owner, BindingResult result, @PathVariable("ownerId") int ownerId,
 			RedirectAttributes redirectAttributes) {

src/main/java/org/springframework/samples/petclinic/owner/PetController.java

@@ -21,6 +21,7 @@ import java.util.Objects;
 import java.util.Optional;
 
 import org.springframework.stereotype.Controller;
+import org.springframework.samples.petclinic.system.FeatureFlagEnabled;
 import org.springframework.ui.ModelMap;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -95,6 +96,7 @@ class PetController {
 		dataBinder.setValidator(new PetValidator());
 	}
 
+	@FeatureFlagEnabled("ADD_PET")
 	@GetMapping("/pets/new")
 	public String initCreationForm(Owner owner, ModelMap model) {
 		Pet pet = new Pet();
@@ -103,6 +105,7 @@ class PetController {
 	}
 
 	@PostMapping("/pets/new")
+	@FeatureFlagEnabled("ADD_PET")
 	public String processCreationForm(Owner owner, @Valid Pet pet, BindingResult result,
 			RedirectAttributes redirectAttributes) {
 
@@ -124,11 +127,13 @@ class PetController {
 		return "redirect:/owners/{ownerId}";
 	}
 
+	@FeatureFlagEnabled("EDIT_PET")
 	@GetMapping("/pets/{petId}/edit")
 	public String initUpdateForm() {
 		return VIEWS_PETS_CREATE_OR_UPDATE_FORM;
 	}
 
+	@FeatureFlagEnabled("EDIT_PET")
 	@PostMapping("/pets/{petId}/edit")
 	public String processUpdateForm(Owner owner, @Valid Pet pet, BindingResult result,
 			RedirectAttributes redirectAttributes) {

src/main/java/org/springframework/samples/petclinic/owner/VisitController.java

@@ -19,6 +19,7 @@ import java.util.Map;
 import java.util.Optional;
 
 import org.springframework.stereotype.Controller;
+import org.springframework.samples.petclinic.system.FeatureFlagEnabled;
 import org.springframework.validation.BindingResult;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -89,6 +90,7 @@ class VisitController {
 	// Spring MVC calls method loadPetWithVisit(...) before processNewVisitForm is
 	// called
 	@PostMapping("/owners/{ownerId}/pets/{petId}/visits/new")
+	@FeatureFlagEnabled("ADD_VISIT")
 	public String processNewVisitForm(@ModelAttribute Owner owner, @PathVariable int petId, @Valid Visit visit,
 			BindingResult result, RedirectAttributes redirectAttributes) {
 		if (result.hasErrors()) {

src/main/java/org/springframework/samples/petclinic/system/FeatureFlagAspect.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.samples.petclinic.system;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.springframework.http.HttpStatus;
+import org.springframework.stereotype.Component;
+import org.springframework.web.server.ResponseStatusException;
+
+@Aspect
+@Component
+public class FeatureFlagAspect {
+
+	private final FeatureFlagHelper featureFlagHelper;
+
+	private final HttpServletRequest request;
+
+	public FeatureFlagAspect(FeatureFlagHelper featureFlagHelper, HttpServletRequest request) {
+		this.featureFlagHelper = featureFlagHelper;
+		this.request = request;
+	}
+
+	@Around("@annotation(featureFlagEnabled)")
+	public Object checkFeatureFlag(ProceedingJoinPoint joinPoint, FeatureFlagEnabled featureFlagEnabled)
+			throws Throwable {
+		String featureFlagKey = featureFlagEnabled.value();
+		Integer ownerId = extractOwnerIdFromPath();
+		boolean enabled = featureFlagHelper.isEnabled(featureFlagKey, ownerId);
+		if (!enabled) {
+			throw new ResponseStatusException(HttpStatus.FORBIDDEN, "Feature '" + featureFlagKey + "' is disabled");
+		}
+		return joinPoint.proceed();
+	}
+
+	private Integer extractOwnerIdFromPath() {
+		String uri = request.getRequestURI();
+		String[] parts = uri.split("/");
+		for (int i = 0; i < parts.length - 1; i++) {
+			if ("owners".equals(parts[i])) {
+				try {
+					return Integer.parseInt(parts[i + 1]);
+				}
+				catch (NumberFormatException e) {
+					return null;
+				}
+			}
+		}
+		return null;
+	}
+
+}

src/main/java/org/springframework/samples/petclinic/system/FeatureFlagController.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.samples.petclinic.system;
+
+import java.util.List;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.samples.petclinic.model.FeatureFlag;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/feature-flags")
+public class FeatureFlagController {
+
+	private final FeatureFlagRepository featureFlagRepository;
+
+	public FeatureFlagController(FeatureFlagRepository featureFlagRepository) {
+		this.featureFlagRepository = featureFlagRepository;
+	}
+
+	@GetMapping
+	public ResponseEntity<List<FeatureFlag>> getAllFlags() {
+		List<FeatureFlag> flags = (List<FeatureFlag>) featureFlagRepository.findAll();
+		return ResponseEntity.ok(flags);
+	}
+
+	@PostMapping
+	public ResponseEntity<FeatureFlag> createFlag(@RequestBody FeatureFlag featureFlag) {
+		FeatureFlag saved = featureFlagRepository.save(featureFlag);
+		return ResponseEntity.status(HttpStatus.CREATED).body(saved);
+	}
+
+	@PutMapping("/{id}")
+	public ResponseEntity<FeatureFlag> updateFlag(@PathVariable Integer id, @RequestBody FeatureFlag featureFlag) {
+		if (!featureFlagRepository.existsById(id)) {
+			return ResponseEntity.notFound().build();
+		}
+		featureFlag.setId(id);
+		FeatureFlag updated = featureFlagRepository.save(featureFlag);
+		return ResponseEntity.ok(updated);
+	}
+
+	@DeleteMapping("/{id}")
+	public ResponseEntity<Void> deleteFlag(@PathVariable Integer id) {
+		if (!featureFlagRepository.existsById(id)) {
+			return ResponseEntity.notFound().build();
+		}
+		featureFlagRepository.findById(id).ifPresent(flag -> {
+			flag.getBlacklistedUsers().clear();
+			flag.getWhitelistedUsers().clear();
+			featureFlagRepository.delete(flag);
+		});
+		return ResponseEntity.noContent().build();
+	}
+
+}

src/main/java/org/springframework/samples/petclinic/system/FeatureFlagEnabled.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.samples.petclinic.system;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to restrict access to a method based on a feature flag.
+ * 
+ * If the feature flag is disabled or globally disabled, the method will not be executed.
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface FeatureFlagEnabled {
+
+	/**
+	 * The key of the feature flag to check.
+	 */
+	String value();
+
+}

src/main/java/org/springframework/samples/petclinic/system/FeatureFlagHelper.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.samples.petclinic.system;
+
+import org.springframework.samples.petclinic.model.FeatureFlag;
+import org.springframework.stereotype.Component;
+
+@Component
+public class FeatureFlagHelper {
+
+	private final FeatureFlagRepository featureFlagRepository;
+
+	public FeatureFlagHelper(FeatureFlagRepository featureFlagRepository) {
+		this.featureFlagRepository = featureFlagRepository;
+	}
+
+	public boolean isEnabled(String flagKey, Integer userId) {
+		FeatureFlag flag = featureFlagRepository.findByKey(flagKey);
+
+		if (flag == null) {
+			return false; // fail-safe default
+		}
+
+		return flag.isAllowedForOwner(userId);
+	}
+
+}

src/main/java/org/springframework/samples/petclinic/system/FeatureFlagRepository.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.samples.petclinic.system;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.samples.petclinic.model.FeatureFlag;
+
+public interface FeatureFlagRepository extends JpaRepository<FeatureFlag, Integer> {
+
+	FeatureFlag findByKey(String key);
+
+}

src/main/java/org/springframework/samples/petclinic/vet/VetController.java

@@ -18,6 +18,7 @@ package org.springframework.samples.petclinic.vet;
 import java.util.List;
 
 import org.springframework.data.domain.Page;
+import org.springframework.samples.petclinic.system.FeatureFlagEnabled;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Controller;
@@ -41,6 +42,7 @@ class VetController {
 		this.vetRepository = vetRepository;
 	}
 
+	@FeatureFlagEnabled("VIEW_VETS")
 	@GetMapping("/vets.html")
 	public String showVetList(@RequestParam(defaultValue = "1") int page, Model model) {
 		// Here we are returning an object of type 'Vets' rather than a collection of Vet
@@ -66,6 +68,7 @@ class VetController {
 		return vetRepository.findAll(pageable);
 	}
 
+	@FeatureFlagEnabled("VIEW_VETS")
 	@GetMapping({ "/vets" })
 	public @ResponseBody Vets showResourcesVetList() {
 		// Here we are returning an object of type 'Vets' rather than a collection of Vet

src/main/resources/db/h2/data.sql

@@ -51,3 +51,18 @@ INSERT INTO visits VALUES (default, 7, '2013-01-01', 'rabies shot');
 INSERT INTO visits VALUES (default, 8, '2013-01-02', 'rabies shot');
 INSERT INTO visits VALUES (default, 8, '2013-01-03', 'neutered');
 INSERT INTO visits VALUES (default, 7, '2013-01-04', 'spayed');
+
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('ADD_PET', false, false, 'Allows adding new pets');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('EDIT_PET', true, false, 'Allows editing existing pets');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('ADD_VISIT', true, false, 'Allows adding new visits');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('OWNER_SEARCH', true, false, 'Allows searching for owners');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('OWNER_EDIT', true, false, 'Allows editing owner information');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('OWNER_ADD', true, false, 'Allows adding new owners');
+INSERT INTO feature_flags (flag_key, is_enabled, globally_disabled, description) VALUES ('VIEW_VETS', true, false, 'Allows viewing vet information');
+
+-- id 5 can't edit owners
+INSERT INTO feature_flag_blacklist (feature_flag_id, owner_id) VALUES (1, 5);
+
+-- only id 1 can add pets and owners
+INSERT INTO feature_flag_whitelist (feature_flag_id, owner_id) VALUES (1, 1);
+INSERT INTO feature_flag_whitelist (feature_flag_id, owner_id) VALUES (6, 1);

src/main/resources/db/h2/schema.sql

@@ -5,6 +5,8 @@ DROP TABLE visits IF EXISTS;
 DROP TABLE pets IF EXISTS;
 DROP TABLE types IF EXISTS;
 DROP TABLE owners IF EXISTS;
+DROP TABLE feature_flags IF EXISTS;
+DROP TABLE feature_flag_blacklist IF EXISTS;
 
 
 CREATE TABLE vets (
@@ -62,3 +64,36 @@ CREATE TABLE visits (
 );
 ALTER TABLE visits ADD CONSTRAINT fk_visits_pets FOREIGN KEY (pet_id) REFERENCES pets (id);
 CREATE INDEX visits_pet_id ON visits (pet_id);
+
+CREATE TABLE feature_flags (
+  id INTEGER GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+  flag_key VARCHAR(100) NOT NULL,
+  is_enabled BOOLEAN,
+  globally_disabled BOOLEAN,
+  rollout_percentage INTEGER,
+  description VARCHAR(255)
+);
+
+CREATE INDEX idx_feature_flags_key ON feature_flags(flag_key);
+
+CREATE TABLE feature_flag_blacklist (
+  feature_flag_id INTEGER NOT NULL,
+  owner_id INTEGER NOT NULL,
+  CONSTRAINT fk_feature_blacklist_flag
+    FOREIGN KEY (feature_flag_id)
+    REFERENCES feature_flags(id),
+  CONSTRAINT fk_blacklist_owner
+    FOREIGN KEY (owner_id)
+    REFERENCES owners(id)
+);
+
+CREATE TABLE feature_flag_whitelist (
+  feature_flag_id INTEGER NOT NULL,
+  owner_id INTEGER NOT NULL,
+  CONSTRAINT fk_feature_whitelist_flag
+    FOREIGN KEY (feature_flag_id)
+    REFERENCES feature_flags(id),
+  CONSTRAINT fk_whitelist_owner
+    FOREIGN KEY (owner_id)
+    REFERENCES owners(id)
+);