Implement Unleash Feature Variants

aruizs · Dec 27, 2023 · 4bcb334 · 4bcb334
1 parent 0046a6e
commit 4bcb334
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Showing 14 changed files with 229 additions and 51 deletions.
diff --git a/README.md b/README.md
@@ -20,7 +20,7 @@ The below table shows what features the SDKs support or plan to support.
 - [x] Unleash context
 - [x] Strategy constrains
 - [x] Application registration
-- [ ] Variants (WIP)
+- [x] Variants
 - [ ] Usage Metrics
 - [ ] Custom stickiness
 
@@ -69,6 +69,29 @@ unleashClient.isEnabled("feature.toogle");
     unleashClient.isEnabled("feature.toogle", context);
 ```
 
+### Getting a Variant
+
+``` 
+    #include "unleash/context.h"
+    ...
+    unleash::Context context{"userId"};
+    auto variant = unleashClient.variant("feature.toogle", context);
+    ...
+    /*
+    The variant response is an instance of the following structure:
+    {
+      std::string name;
+      unsigned int weight;
+      bool enabled;
+      bool feature_enabled;
+      std::string payload;
+    }
+    */
+```
+
+For more information about variants, see the [Variant documentation](https://docs.getunleash.io/advanced/toggle_variants).
+
+
 ## Integration
 
 ### Building with CMake

diff --git a/include/unleash/feature.h b/include/unleash/feature.h
@@ -1,6 +1,7 @@
 #ifndef UNLEASH_FEATURE_H
 #define UNLEASH_FEATURE_H
 #include "unleash/strategies/strategy.h"
+#include "unleash/variants/variant.h"
 #include <memory>
 #include <string>
 #include <vector>
@@ -10,12 +11,17 @@ class Context;
 class Feature {
 public:
     Feature(std::string name, std::vector<std::unique_ptr<Strategy>> strategies, bool enable);
+    void setVariants(std::pair<std::vector<std::unique_ptr<Variant>>, unsigned int> variants);
     bool isEnabled(const Context &context) const;
+    variant_t getVariant(const Context &context) const;
 
 private:
+    bool checkVariant(const unleash::Variant &variantInput, variant_t &variantResponse, const Context &context) const;
+
     std::string m_name;
     bool m_enabled;
     std::vector<std::unique_ptr<Strategy>> m_strategies;
+    std::pair<std::vector<std::unique_ptr<Variant>>, unsigned int> m_variants;
 };
 }  // namespace unleash
 #endif  //UNLEASH_FEATURE_H
diff --git a/include/unleash/unleashclient.h b/include/unleash/unleashclient.h
@@ -14,6 +14,7 @@ namespace unleash {
 
 class UnleashClientBuilder;
 class Context;
+struct variant_t;
 
 class UNLEASH_EXPORT UnleashClient {
 public:
@@ -27,6 +28,8 @@ class UNLEASH_EXPORT UnleashClient {
     void initializeClient();
     bool isEnabled(const std::string &flag);
     bool isEnabled(const std::string &flag, const Context &context);
+    variant_t variant(const std::string &flag, const Context &context);
+
 
 private:
     UnleashClient(std::string name, std::string url);

diff --git a/include/unleash/strategies/murmur3hash.h → include/unleash/utils/murmur3hash.h b/include/unleash/strategies/murmur3hash.h → include/unleash/utils/murmur3hash.h
@@ -4,14 +4,14 @@
 // MurmurHash3 was written by Austin Appleby, and is placed in the public
 // domain. The author hereby disclaims copyright to this source code.
 //-----------------------------------------------------------------------------
-#include <stdint.h>
+#include <cstdint>
 #include <string>
 
 namespace unleash {
 
 void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out);
 
-uint32_t normalizedMurmur3(const std::string &key, uint32_t seed = 0);
+uint32_t normalizedMurmur3(const std::string &key, uint32_t modulus = 100, uint32_t seed = 0);
 
 
 }  // namespace unleash

diff --git a/include/unleash/variants/variant.h b/include/unleash/variants/variant.h
@@ -0,0 +1,40 @@
+#ifndef UNLEASH_VARIANTS_H
+#define UNLEASH_VARIANTS_H
+#include <string>
+#include <vector>
+
+namespace unleash {
+
+class Context;
+
+struct Override {
+    std::string contextName;
+    std::vector<std::string> values;
+};
+
+struct variant_t {
+    std::string name;
+    unsigned int weight;
+    bool enabled;
+    bool feature_enabled;
+    std::string payload;
+};
+
+class Variant {
+public:
+    Variant(std::string name, unsigned int weight, std::string_view payload, std::string_view overrides);
+    unsigned int getWeight() const { return m_weight; }
+    const std::string &getName() const { return m_name; }
+    const std::vector<Override> &getOverrides() const { return m_overrides; }
+    const std::string &getPayload() const { return m_payload; }
+
+private:
+    std::string m_name;
+    unsigned int m_weight;
+    std::string m_payload;
+    std::vector<Override> m_overrides;
+};
+}  // namespace unleash
+
+
+#endif  //UNLEASH_VARIANTS_H
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
@@ -1,27 +1,28 @@
 
 add_library(
-  unleash
-  unleashclient.cpp
-  feature.cpp
-  api/cprclient.cpp
-  strategies/strategy.cpp
-  strategies/default.cpp
-  strategies/userwithid.cpp
-  strategies/applicationhostname.cpp
-  strategies/flexiblerollout.cpp
-  strategies/remoteaddress.cpp
-  strategies/murmur3hash.cpp
-  strategies/gradualrolloutuserid.cpp
-  strategies/gradualrolloutsessionid.cpp
-  strategies/gradualrolloutrandom.cpp)
+        unleash
+        unleashclient.cpp
+        feature.cpp
+        api/cprclient.cpp
+        strategies/strategy.cpp
+        strategies/default.cpp
+        strategies/userwithid.cpp
+        strategies/applicationhostname.cpp
+        strategies/flexiblerollout.cpp
+        strategies/remoteaddress.cpp
+        utils/murmur3hash.cpp
+        strategies/gradualrolloutuserid.cpp
+        strategies/gradualrolloutsessionid.cpp
+        strategies/gradualrolloutrandom.cpp
+        variants/variant.cpp)
 
 add_library(unleash::unleash ALIAS unleash)
 target_include_directories(
-  unleash PUBLIC "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>")
+        unleash PUBLIC "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>")
 target_link_libraries(unleash PRIVATE cpr::cpr
-                                      nlohmann_json::nlohmann_json)
+        nlohmann_json::nlohmann_json)
 set_target_properties(unleash PROPERTIES VERSION ${unleash_VERSION}
-                                         SOVERSION ${unleash_VERSION_MAJOR})
+        SOVERSION ${unleash_VERSION_MAJOR})
 
 target_compile_features(unleash PUBLIC cxx_std_17)
 

diff --git a/src/feature.cpp b/src/feature.cpp
@@ -1,8 +1,12 @@
 #include "unleash/feature.h"
+#include "unleash/utils/murmur3hash.h"
+#include <algorithm>
+#include <numeric>
 
 namespace unleash {
 Feature::Feature(std::string name, std::vector<std::unique_ptr<Strategy>> strategies, bool enable)
     : m_name(std::move(name)), m_enabled(enable), m_strategies(std::move(strategies)) {}
+
 bool Feature::isEnabled(const Context &context) const {
     if (m_enabled) {
         if (m_strategies.empty()) return true;
@@ -12,4 +16,49 @@ bool Feature::isEnabled(const Context &context) const {
     }
     return false;
 }
+
+void Feature::setVariants(std::pair<std::vector<std::unique_ptr<Variant>>, unsigned int> variants) {
+    m_variants = std::move(variants);
+}
+
+variant_t Feature::getVariant(const unleash::Context &context) const {
+    variant_t variant{"disabled", 0, false, false};
+    if (!isEnabled(context)) { return variant; }
+
+    variant.feature_enabled = true;
+    if (m_variants.first.empty()) { return variant; }
+
+    variant.enabled = true;
+    constexpr uint32_t seed = 86028157;
+    auto normalizedValue = normalizedMurmur3(m_name + ":" + context.userId, m_variants.second, seed);
+    unsigned int weight = 0;
+    for (auto &eachVariant : m_variants.first) {
+        if (!eachVariant->getOverrides().empty() && checkVariant(*eachVariant, variant, context)) break;
+
+        weight += eachVariant->getWeight();
+        if (normalizedValue <= weight) {
+            variant.name = eachVariant->getName();
+            variant.payload = eachVariant->getPayload();
+            break;
+        }
+    }
+
+    return variant;
+}
+
+bool Feature::checkVariant(const unleash::Variant &variantInput, variant_t &variantResponse,
+                           const unleash::Context &context) const {
+    if (auto contextIt = std::find_if(variantInput.getOverrides().begin(), variantInput.getOverrides().end(),
+                                      [](const Override &o) { return o.contextName == "userId"; });
+        contextIt != variantInput.getOverrides().end()) {
+        auto valuesIt = std::find((*contextIt).values.begin(), (*contextIt).values.end(), context.userId);
+
+        if (valuesIt != (*contextIt).values.end()) {
+            variantResponse.name = variantInput.getName();
+            variantResponse.payload = variantInput.getPayload();
+            return true;
+        }
+    }
+    return false;
+};
 }  // namespace unleash
diff --git a/src/strategies/flexiblerollout.cpp b/src/strategies/flexiblerollout.cpp
@@ -1,5 +1,5 @@
 #include "unleash/strategies/flexiblerollout.h"
-#include "unleash/strategies/murmur3hash.h"
+#include "unleash/utils/murmur3hash.h"
 #include <nlohmann/json.hpp>
 #include <random>
 

diff --git a/src/strategies/gradualrolloutsessionid.cpp b/src/strategies/gradualrolloutsessionid.cpp
@@ -1,5 +1,5 @@
 #include "unleash/strategies/gradualrolloutsessionid.h"
-#include "unleash/strategies/murmur3hash.h"
+#include "unleash/utils/murmur3hash.h"
 #include <nlohmann/json.hpp>
 
 namespace unleash {

diff --git a/src/strategies/gradualrolloutuserid.cpp b/src/strategies/gradualrolloutuserid.cpp
@@ -1,5 +1,5 @@
 #include "unleash/strategies/gradualrolloutuserid.h"
-#include "unleash/strategies/murmur3hash.h"
+#include "unleash/utils/murmur3hash.h"
 #include <nlohmann/json.hpp>
 
 namespace unleash {

diff --git a/src/unleashclient.cpp b/src/unleashclient.cpp
@@ -110,20 +110,50 @@ bool UnleashClient::isEnabled(const std::string &flag, const Context &context) {
     return false;
 }
 
+variant_t UnleashClient::variant(const std::string &flag, const unleash::Context &context) {
+    variant_t variant{"disabled", 0, false, false};
+    if (m_isInitialized) {
+        variant.feature_enabled = isEnabled(flag, context);
+        if (auto search = m_features.find(flag); search != m_features.end()) {
+            std::cout << "variant" << std::endl;
+            return m_features.at(flag).getVariant(context);
+        }
+    }
+    return variant;
+}
+
 UnleashClient::featuresMap_t UnleashClient::loadFeatures(std::string_view features) const {
     const auto featuresJson = nlohmann::json::parse(features);
     featuresMap_t featuresMap;
     for (const auto &[key, value] : featuresJson["features"].items()) {
-        std::vector<std::unique_ptr<Strategy>> m_strategies;
+        // Load strategies
+        std::vector<std::unique_ptr<Strategy>> strategies;
         for (const auto &[strategyKey, strategyValue] : value["strategies"].items()) {
             std::string strategyParameters;
             if (strategyValue.contains("parameters")) strategyParameters = strategyValue["parameters"].dump();
             std::string strategyConstraints;
             if (strategyValue.contains("constraints")) { strategyConstraints = strategyValue["constraints"].dump(); }
-            m_strategies.push_back(Strategy::createStrategy(strategyValue["name"].get<std::string>(),
-                                                            strategyParameters, strategyConstraints));
+            strategies.push_back(Strategy::createStrategy(strategyValue["name"].get<std::string>(), strategyParameters,
+                                                          strategyConstraints));
+        }
+        Feature newFeature(value["name"], std::move(strategies), value["enabled"]);
+        // Load variants
+        std::pair<std::vector<std::unique_ptr<Variant>>, unsigned int> variants;
+        if (value.contains("variants")) {
+            unsigned int totalWeight = 0;
+            for (const auto &[variantKey, variantValue] : value["variants"].items()) {
+                std::string variantPayload;
+                if (variantValue.contains("payload")) variantPayload = variantValue["payload"].dump();
+                std::string variantOverrides;
+                if (variantValue.contains("overrides")) variantOverrides = variantValue["overrides"].dump();
+                variants.first.push_back(std::make_unique<Variant>(variantValue["name"], variantValue["weight"],
+                                                                   variantPayload, variantOverrides));
+                totalWeight += variantValue["weight"].get<unsigned int>();
+            }
+            variants.second = totalWeight;
+            newFeature.setVariants(std::move(variants));
         }
-        featuresMap.try_emplace(value["name"], value["name"], std::move(m_strategies), value["enabled"]);
+        featuresMap.try_emplace(value["name"], std::move(newFeature));
     }
     return featuresMap;
 }

diff --git a/src/strategies/murmur3hash.cpp → src/utils/murmur3hash.cpp b/src/strategies/murmur3hash.cpp → src/utils/murmur3hash.cpp
@@ -1,4 +1,5 @@
-#include "unleash/strategies/murmur3hash.h"
+#include "unleash/utils/murmur3hash.h"
+#include <iostream>
 
 //-----------------------------------------------------------------------------
 // MurmurHash3 was written by Austin Appleby, and is placed in the public
@@ -69,22 +70,11 @@ FORCE_INLINE uint32_t fmix32(uint32_t h) {
     return h;
 }
 
-//----------
-
-FORCE_INLINE uint64_t fmix64(uint64_t k) {
-    k ^= k >> 33;
-    k *= BIG_CONSTANT(0xff51afd7ed558ccd);
-    k ^= k >> 33;
-    k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
-    k ^= k >> 33;
-
-    return k;
-}
 
 //-----------------------------------------------------------------------------
 
 void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out) {
-    const uint8_t *data = (const uint8_t *) key;
+    const auto *data = (const uint8_t *) key;
     const int nblocks = len / 4;
 
     uint32_t h1 = seed;
@@ -95,7 +85,7 @@ void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out) {
     //----------
     // body
 
-    const uint32_t *blocks = (const uint32_t *) (data + nblocks * 4);
+    const auto *blocks = (const uint32_t *) (data + nblocks * 4);
 
     for (int i = -nblocks; i; i++) {
         uint32_t k1 = getblock32(blocks, i);
@@ -112,7 +102,7 @@ void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out) {
     //----------
     // tail
 
-    const uint8_t *tail = (const uint8_t *) (data + nblocks * 4);
+    const auto *tail = data + nblocks * 4;
 
     uint32_t k1 = 0;
 
@@ -127,7 +117,7 @@ void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out) {
             k1 = ROTL32(k1, 15);
             k1 *= c2;
             h1 ^= k1;
-    };
+    }
 
     //----------
     // finalization
@@ -139,10 +129,10 @@ void murmurHash3X8632(const void *key, int len, uint32_t seed, void *out) {
     *(uint32_t *) out = h1;
 }
 
-uint32_t normalizedMurmur3(const std::string &key, uint32_t seed) {
+uint32_t normalizedMurmur3(const std::string &key, uint32_t modulus, uint32_t seed) {
     uint32_t murmur3Hash;
-    murmurHash3X8632(key.c_str(), key.length(), seed, &murmur3Hash);
-    murmur3Hash %= 100;
+    murmurHash3X8632(key.c_str(), static_cast<int>(key.length()), seed, &murmur3Hash);
+    murmur3Hash %= modulus;
     murmur3Hash += 1;
     return murmur3Hash;
 }