feat: generate analytic events from evaluations

apps/hello-cpp/main.cpp

@@ -22,7 +22,7 @@ using launchdarkly::client_side::flag_manager::detail::FlagManager;
 using launchdarkly::client_side::flag_manager::detail::FlagUpdater;
 
 int main() {
-    Logger logger(std::make_unique<ConsoleBackend>(LogLevel::kDebug, "Hello"));
+    Logger logger(std::make_unique<ConsoleBackend>("Hello"));
 
     net::io_context ioc;
 
@@ -45,6 +45,8 @@ int main() {
                                 std::chrono::seconds{30}))
                             .WithReasons(true)
                             .UseReport(true))
+            .Events(launchdarkly::client_side::EventsBuilder().FlushInterval(
+                std::chrono::seconds(5)))
             .Build()
             .value(),
         ContextBuilder().kind("user", "ryan").build());
@@ -58,8 +60,9 @@ int main() {
 
     client.WaitForReadySync(std::chrono::seconds(30));
 
-    auto value = client.BoolVariation("my-boolean-flag", false);
-    LD_LOG(logger, LogLevel::kInfo) << "Value was: " << value;
+    auto value = client.BoolVariationDetail("my-bool-flag", false);
+    LD_LOG(logger, LogLevel::kInfo) << "Value was: " << *value;
+    LD_LOG(logger, LogLevel::kInfo) << "Reason was: " << value.Reason();
 
     // Sit around.
     std::cout << "Press enter to exit" << std::endl;

libs/client-sdk/include/launchdarkly/client_side/api.hpp

@@ -7,10 +7,11 @@
 #include <memory>
 #include <optional>
 #include <thread>
-
 #include <tl/expected.hpp>
+#include <tuple>
 #include "config/client.hpp"
 #include "context.hpp"
+#include "data/evaluation_detail.hpp"
 #include "error.hpp"
 #include "launchdarkly/client_side/data_source.hpp"
 #include "launchdarkly/client_side/data_sources/detail/data_source_status_manager.hpp"
@@ -30,6 +31,8 @@ class Client {
     Client& operator=(Client) = delete;
     Client& operator=(Client&& other) = delete;
 
+    bool Initialized() const;
+
     using FlagKey = std::string;
     [[nodiscard]] std::unordered_map<FlagKey, Value> AllFlags() const;
 
@@ -45,28 +48,48 @@ class Client {
 
     bool BoolVariation(FlagKey const& key, bool default_value);
 
+    EvaluationDetail<bool> BoolVariationDetail(FlagKey const& key,
+                                               bool default_value);
+
     std::string StringVariation(FlagKey const& key, std::string default_value);
 
+    EvaluationDetail<std::string> StringVariationDetail(
+        FlagKey const& key,
+        std::string default_value);
+
     double DoubleVariation(FlagKey const& key, double default_value);
 
+    EvaluationDetail<double> DoubleVariationDetail(FlagKey const& key,
+                                                   double default_value);
+
     int IntVariation(FlagKey const& key, int default_value);
 
+    EvaluationDetail<int> IntVariationDetail(FlagKey const& key,
+                                             int default_value);
+
     Value JsonVariation(FlagKey const& key, Value default_value);
 
+    EvaluationDetail<Value> JsonVariationDetail(FlagKey const& key,
+                                                Value default_value);
+
     data_sources::IDataSourceStatusProvider& DataSourceStatus();
 
     void WaitForReadySync(std::chrono::seconds timeout);
 
     ~Client();
 
    private:
-    Value VariationInternal(FlagKey const& key, Value default_value);
+    template <typename T>
+    [[nodiscard]] EvaluationDetail<T> VariationInternal(FlagKey const& key,
+                                                        Value default_value,
+                                                        bool check_type,
+                                                        bool detailed);
     void TrackInternal(std::string event_name,
                        std::optional<Value> data,
                        std::optional<double> metric_value);
 
     bool initialized_;
-    std::mutex init_mutex_;
+    mutable std::mutex init_mutex_;
     std::condition_variable init_waiter_;
 
     data_sources::detail::DataSourceStatusManager status_manager_;
@@ -80,6 +103,8 @@ class Client {
     std::unique_ptr<IEventProcessor> event_processor_;
     std::unique_ptr<IDataSource> data_source_;
     std::thread run_thread_;
+
+    bool eval_reasons_available_;
 };
 
 }  // namespace launchdarkly::client_side

libs/client-sdk/src/api.cpp

@@ -41,7 +41,8 @@ Client::Client(Config config, Context context)
                                   flag_updater_,
                                   status_manager_,
                                   logger_)),
-      initialized_(false) {
+      initialized_(false),
+      eval_reasons_available_(config.DataSourceConfig().with_reasons) {
     if (config.Events().Enabled()) {
         event_processor_ = std::make_unique<detail::EventProcessor>(
             ioc_.get_executor(), config, logger_);
@@ -67,6 +68,11 @@ Client::Client(Config config, Context context)
     run_thread_ = std::move(std::thread([&]() { ioc_.run(); }));
 }
 
+bool Client::Initialized() const {
+    std::unique_lock lock(init_mutex_);
+    return initialized_;
+}
+
 std::unordered_map<Client::FlagKey, Value> Client::AllFlags() const {
     return {};
 }
@@ -100,34 +106,150 @@ void Client::AsyncIdentify(Context context) {
         std::chrono::system_clock::now(), std::move(context)});
 }
 
-Value Client::VariationInternal(FlagKey const& key, Value default_value) {
-    auto res = flag_manager_.Get(key);
-    if (res && res->flag) {
-        return res->flag->detail().value();
+// TODO(cwaldren): refactor VariationInternal so it isn't so long and mixing up
+// multiple concerns.
+template <typename T>
+EvaluationDetail<T> Client::VariationInternal(FlagKey const& key,
+                                              Value default_value,
+                                              bool check_type,
+                                              bool detailed) {
+    auto desc = flag_manager_.Get(key);
+
+    events::client::FeatureEventParams event = {
+        std::chrono::system_clock::now(),
+        key,
+        context_,
+        default_value,
+        default_value,
+        std::nullopt,
+        std::nullopt,
+        std::nullopt,
+        false,
+        std::nullopt,
+    };
+
+    if (!desc || !desc->flag) {
+        if (!Initialized()) {
+            LD_LOG(logger_, LogLevel::kWarn)
+                << "LaunchDarkly client has not yet been initialized. "
+                   "Returning default value";
+
+            // TODO: SC-199918
+            auto error_reason = EvaluationReason("CLIENT_NOT_READY");
+            if (eval_reasons_available_) {
+                event.reason = error_reason;
+            }
+            event_processor_->AsyncSend(std::move(event));
+            return EvaluationDetail<T>(default_value, std::nullopt,
+                                       std::move(error_reason));
+        }
+
+        LD_LOG(logger_, LogLevel::kInfo)
+            << "Unknown feature flag " << key << "; returning default value";
+
+        auto error_reason = EvaluationReason("FLAG_NOT_FOUND");
+        if (eval_reasons_available_) {
+            event.reason = error_reason;
+        }
+        event_processor_->AsyncSend(std::move(event));
+        return EvaluationDetail<T>(default_value, std::nullopt,
+                                   std::move(error_reason));
+
+    } else if (!Initialized()) {
+        LD_LOG(logger_, LogLevel::kWarn)
+            << "LaunchDarkly client has not yet been initialized. "
+               "Returning cached value";
+    }
+
+    assert(desc->flag);
+
+    auto const& flag = *(desc->flag);
+    auto const& detail = flag.detail();
+
+    if (check_type && default_value.type() != Value::Type::kNull &&
+        detail.value().type() != default_value.type()) {
+        auto error_reason = EvaluationReason("WRONG_TYPE");
+        if (eval_reasons_available_) {
+            event.reason = error_reason;
+        }
+        event_processor_->AsyncSend(std::move(event));
+        return EvaluationDetail<T>(default_value, std::nullopt, error_reason);
+    }
+
+    event.value = detail.value();
+    event.variation = detail.variation_index();
+
+    if (detailed || flag.track_reason()) {
+        event.reason = detail.reason();
+    }
+
+    event.version = flag.flag_version().value_or(flag.version());
+    event.require_full_event = flag.track_events();
+    if (auto date = flag.debug_events_until_date()) {
+        event.debug_events_until_date = events::Date{*date};
     }
-    return default_value;
+
+    event_processor_->AsyncSend(std::move(event));
+
+    // TODO: this isn't a valid error, figure out how to handle if reason is
+    // missing.
+    EvaluationReason returned_reason("UNKNOWN");
+    if (detail.reason()) {
+        returned_reason = detail.reason()->get();
+    }
+    return EvaluationDetail<T>(detail.value(), detail.variation_index(),
+                               returned_reason);
+}
+
+EvaluationDetail<bool> Client::BoolVariationDetail(Client::FlagKey const& key,
+                                                   bool default_value) {
+    return VariationInternal<bool>(key, default_value, true, true);
 }
 
 bool Client::BoolVariation(Client::FlagKey const& key, bool default_value) {
-    return VariationInternal(key, default_value).as_bool();
+    return *VariationInternal<bool>(key, default_value, true, false);
+}
+
+EvaluationDetail<std::string> Client::StringVariationDetail(
+    Client::FlagKey const& key,
+    std::string default_value) {
+    return VariationInternal<std::string>(key, std::move(default_value), true,
+                                          true);
 }
 
 std::string Client::StringVariation(Client::FlagKey const& key,
                                     std::string default_value) {
-    return VariationInternal(key, std::move(default_value)).as_string();
+    return *VariationInternal<std::string>(key, std::move(default_value), true,
+                                           false);
+}
+
+EvaluationDetail<double> Client::DoubleVariationDetail(
+    Client::FlagKey const& key,
+    double default_value) {
+    return VariationInternal<double>(key, default_value, true, true);
 }
 
 double Client::DoubleVariation(Client::FlagKey const& key,
                                double default_value) {
-    return VariationInternal(key, default_value).as_double();
+    return *VariationInternal<double>(key, default_value, true, false);
 }
 
+EvaluationDetail<int> Client::IntVariationDetail(Client::FlagKey const& key,
+                                                 int default_value) {
+    return VariationInternal<int>(key, default_value, true, true);
+}
 int Client::IntVariation(Client::FlagKey const& key, int default_value) {
-    return VariationInternal(key, default_value).as_int();
+    return *VariationInternal<int>(key, default_value, true, false);
+}
+
+EvaluationDetail<Value> Client::JsonVariationDetail(Client::FlagKey const& key,
+                                                    Value default_value) {
+    return VariationInternal<Value>(key, std::move(default_value), false, true);
 }
 
 Value Client::JsonVariation(Client::FlagKey const& key, Value default_value) {
-    return VariationInternal(key, std::move(default_value));
+    return *VariationInternal<Value>(key, std::move(default_value), false,
+                                     false);
 }
 
 data_sources::IDataSourceStatusProvider& Client::DataSourceStatus() {

libs/client-sdk/tests/client_test.cpp

@@ -1,19 +1,82 @@
 #include <gtest/gtest.h>
 #include <launchdarkly/client_side/api.hpp>
+#include <map>
 #include "context_builder.hpp"
 
 using namespace launchdarkly;
+using namespace launchdarkly::client_side;
 
-TEST(ClientTest, ConstructClientWithConfig) {
-    tl::expected<client_side::Config, Error> config =
-        client_side::ConfigBuilder("sdk-123").Build();
-
+TEST(ClientTest, ClientConstructedWithMinimalConfigAndContext) {
+    tl::expected<Config, Error> config = ConfigBuilder("sdk-123").Build();
     ASSERT_TRUE(config);
 
-    auto context = ContextBuilder().kind("cat", "shadow").build();
+    Context context = ContextBuilder().kind("cat", "shadow").build();
+
+    Client client(std::move(*config), context);
+}
 
-    client_side::Client client(std::move(*config), context);
+TEST(ClientTest, AllFlagsIsEmpty) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
 
     ASSERT_TRUE(client.AllFlags().empty());
-    ASSERT_TRUE(client.BoolVariation("cat-food", true));
+}
+
+TEST(ClientTest, BoolVariationDefaultPassesThrough) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
+
+    const std::string flag = "extra-cat-food";
+    std::vector<bool> values = {true, false};
+    for (auto const& v : values) {
+        ASSERT_EQ(client.BoolVariation(flag, v), v);
+        ASSERT_EQ(*client.BoolVariationDetail(flag, v), v);
+    }
+}
+
+TEST(ClientTest, StringVariationDefaultPassesThrough) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
+    const std::string flag = "treat";
+    std::vector<std::string> values = {"chicken", "fish", "cat-grass"};
+    for (auto const& v : values) {
+        ASSERT_EQ(client.StringVariation(flag, v), v);
+        ASSERT_EQ(*client.StringVariationDetail(flag, v), v);
+    }
+}
+
+TEST(ClientTest, IntVariationDefaultPassesThrough) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
+    const std::string flag = "weight";
+    std::vector<int> values = {0, 12, 13, 24, 1000};
+    for (auto const& v : values) {
+        ASSERT_EQ(client.IntVariation("weight", v), v);
+        ASSERT_EQ(*client.IntVariationDetail("weight", v), v);
+    }
+}
+
+TEST(ClientTest, DoubleVariationDefaultPassesThrough) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
+    const std::string flag = "weight";
+    std::vector<double> values = {0.0, 12.0, 13.0, 24.0, 1000.0};
+    for (auto const& v : values) {
+        ASSERT_EQ(client.DoubleVariation(flag, v), v);
+        ASSERT_EQ(*client.DoubleVariationDetail(flag, v), v);
+    }
+}
+
+TEST(ClientTest, JsonVariationDefaultPassesThrough) {
+    Client client(ConfigBuilder("sdk-123").Build().value(),
+                  ContextBuilder().kind("cat", "shadow").build());
+
+    const std::string flag = "assorted-values";
+    std::vector<Value> values = {
+        Value({"running", "jumping"}), Value(3), Value(1.0), Value(true),
+        Value(std::map<std::string, Value>{{"weight", 20}})};
+    for (auto const& v : values) {
+        ASSERT_EQ(client.JsonVariation(flag, v), v);
+        ASSERT_EQ(*client.JsonVariationDetail(flag, v), v);
+    }
 }