feat: add Unleash provider (#424)

Signed-off-by: liran2000 <liran2000@gmail.com>
Co-authored-by: Todd Baert <todd.baert@dynatrace.com>
Co-authored-by: Ivar Conradi Østhus <ivarconr@gmail.com>

.github/component_owners.yml

@@ -19,6 +19,9 @@ components:
     - thomaspoignant
   providers/jsonlogic-eval-provider:
     - justinabrahms
+  providers/unleash:
+    - liran2000
+    - sighphyre
 
 ignored-authors:
   - renovate-bot

.release-please-manifest.json

@@ -4,5 +4,6 @@
   "providers/go-feature-flag": "0.2.13",
   "providers/flagsmith": "0.0.8",
   "providers/env-var": "0.0.4",
-  "providers/jsonlogic-eval-provider": "1.0.0"
+  "providers/jsonlogic-eval-provider": "1.0.0",
+  "providers/unleash": "0.0.1-alpha"
 }

pom.xml

@@ -33,6 +33,7 @@
         <module>providers/go-feature-flag</module>
         <module>providers/jsonlogic-eval-provider</module>
         <module>providers/env-var</module>
+        <module>providers/unleash</module>
     </modules>
 
     <scm>

providers/unleash/README.md

@@ -0,0 +1,62 @@
+# Unofficial Unleash OpenFeature Provider for Java
+
+[Unleash](https://getunleash.io) OpenFeature Provider can provide usage for Unleash via OpenFeature Java SDK.
+
+## Installation
+
+<!-- x-release-please-start-version -->
+
+```xml
+
+<dependency>
+    <groupId>dev.openfeature.contrib.providers</groupId>
+    <artifactId>unleash</artifactId>
+    <version>0.0.1-alpha</version>
+</dependency>
+```
+
+<!-- x-release-please-end-version -->
+
+## Concepts
+* Boolean evaluation gets feature enabled status.
+* String evaluation gets feature variant value.
+
+## Usage
+Unleash OpenFeature Provider is using Unleash Java SDK.
+
+### Usage Example
+
+```
+FeatureProvider unleashProvider = new UnleashProvider(unleashProviderConfig);
+OpenFeatureAPI.getInstance().setProviderAndWait(unleashProvider);
+boolean featureEnabled = client.getBooleanValue(FLAG_NAME, false);
+
+// Context parameters are optional, not mandatory to fill all parameters
+MutableContext evaluationContext = new MutableContext();
+evaluationContext.add("userId", userIdValue);
+evaluationContext.add("currentTime", String.valueOf(currentTimeValue));
+evaluationContext.add("sessionId", sessionIdValue);
+evaluationContext.add("remoteAddress", remoteAddressValue);
+evaluationContext.add("environment", environmentValue);
+evaluationContext.add("appName", appNameValue);
+evaluationContext.add(customPropertyKey, customPropertyValue);
+featureEnabled = client.getBooleanValue(FLAG_NAME, false, evaluationContext);
+
+String variantValue = client.getStringValue(FLAG_NAME, "");
+```
+
+See [UnleashProviderTest.java](./src/test/java/dev/openfeature/contrib/providers/unleash/UnleashProviderTest.java) for more information.
+
+### Additional Usage Details
+
+* When default value is used and returned, default variant is not used and variant name is not set.
+* json/csv payloads are evaluated via object evaluation as what returned from Unleash - string, wrapped with Value.
+* Additional evaluation data can be received via flag metadata, such as:
+  * *enabled* - boolean
+  * *variant-stickiness* - string
+  * *payload-type* - string, optional
+
+## Unleash Provider Tests Strategies
+
+Unit test based on Unleash instance with Unleash features schema file, with WireMock for API mocking.  
+See [UnleashProviderTest.java](./src/test/java/dev/openfeature/contrib/providers/unleash/UnleashProviderTest.java) for more information.

providers/unleash/lombok.config

@@ -0,0 +1,5 @@
+# This file is needed to avoid errors throw by findbugs when working with lombok.
+lombok.addSuppressWarnings = true
+lombok.addLombokGeneratedAnnotation = true
+config.stopBubbling = true
+lombok.extern.findbugs.addSuppressFBWarnings = true

providers/unleash/pom.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>dev.openfeature.contrib</groupId>
+        <artifactId>parent</artifactId>
+        <version>0.1.0</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <groupId>dev.openfeature.contrib.providers</groupId>
+    <artifactId>unleash</artifactId>
+    <version>0.0.1-alpha</version> <!--x-release-please-version -->
+
+    <name>unleash</name>
+    <description>unleash provider for Java</description>
+    <url>https://www.getunleash.io/</url>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.getunleash</groupId>
+            <artifactId>unleash-client-java</artifactId>
+            <version>8.3.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.9</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.github.tomakehurst</groupId>
+            <artifactId>wiremock-jre8</artifactId>
+            <version>2.35.1</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-slf4j2-impl</artifactId>
+            <version>2.20.0</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+</project>

providers/unleash/src/main/java/dev/openfeature/contrib/providers/unleash/ContextTransformer.java

@@ -0,0 +1,50 @@
+package dev.openfeature.contrib.providers.unleash;
+
+import dev.openfeature.sdk.EvaluationContext;
+import io.getunleash.UnleashContext;
+
+import java.time.ZonedDateTime;
+
+/**
+ * Transformer from Unleash context to OpenFeature context and vice versa.
+ */
+public class ContextTransformer {
+
+    public static final String CONTEXT_APP_NAME = "appName";
+    public static final String CONTEXT_USER_ID = "userId";
+    public static final String CONTEXT_ENVIRONMENT = "environment";
+    public static final String CONTEXT_REMOTE_ADDRESS = "remoteAddress";
+    public static final String CONTEXT_SESSION_ID = "sessionId";
+    public static final String CONTEXT_CURRENT_TIME = "currentTime";
+
+    protected static UnleashContext transform(EvaluationContext ctx) {
+        UnleashContext.Builder unleashContextBuilder = new UnleashContext.Builder();
+        ctx.asObjectMap().forEach((k, v) -> {
+            switch (k) {
+                case CONTEXT_APP_NAME:
+                    unleashContextBuilder.appName(String.valueOf(v));
+                    break;
+                case CONTEXT_USER_ID:
+                    unleashContextBuilder.userId(String.valueOf(v));
+                    break;
+                case CONTEXT_ENVIRONMENT:
+                    unleashContextBuilder.environment(String.valueOf(v));
+                    break;
+                case CONTEXT_REMOTE_ADDRESS:
+                    unleashContextBuilder.remoteAddress(String.valueOf(v));
+                    break;
+                case CONTEXT_SESSION_ID:
+                    unleashContextBuilder.sessionId(String.valueOf(v));
+                    break;
+                case CONTEXT_CURRENT_TIME:
+                    unleashContextBuilder.currentTime(ZonedDateTime.parse(String.valueOf(v)));
+                    break;
+                default:
+                    unleashContextBuilder.addProperty(k, String.valueOf(v));
+                    break;
+            }
+        });
+        return unleashContextBuilder.build();
+    }
+
+}