feat: Add client support for streaming.

apps/hello-cpp/main.cpp

@@ -4,46 +4,38 @@
 #include <boost/asio/io_context.hpp>
 
 #include "console_backend.hpp"
-#include "logger.hpp"
+#include "context_builder.hpp"
+#include "launchdarkly/client_side/data_sources/detail/streaming_data_source.hpp"
 
 #include <iostream>
-#include <utility>
 
 namespace net = boost::asio;  // from <boost/asio.hpp>
 
 using launchdarkly::ConsoleBackend;
+using launchdarkly::ContextBuilder;
 using launchdarkly::Logger;
 using launchdarkly::LogLevel;
+using launchdarkly::client_side::Client;
+using launchdarkly::client_side::ConfigBuilder;
+using launchdarkly::client_side::flag_manager::detail::FlagManager;
+using launchdarkly::client_side::flag_manager::detail::FlagUpdater;
 
 int main() {
-    Logger logger(std::make_unique<ConsoleBackend>("Hello"));
+    Logger logger(std::make_unique<ConsoleBackend>(LogLevel::kDebug, "Hello"));
 
     net::io_context ioc;
 
     char const* key = std::getenv("STG_SDK_KEY");
     if (!key) {
-        std::cout << "Set environment variable STG_SDK_KEY to the sdk key\n";
-        return 1;
-    }
-    auto client =
-        launchdarkly::sse::Builder(ioc.get_executor(),
-                                   "https://stream-stg.launchdarkly.com/all")
-            .header("Authorization", key)
-            .receiver([&](launchdarkly::sse::Event ev) {
-                LD_LOG(logger, LogLevel::kInfo) << "event: " << ev.type();
-                LD_LOG(logger, LogLevel::kInfo)
-                    << "data: " << std::move(ev).take();
-            })
-            .logger([&](std::string msg) {
-                LD_LOG(logger, LogLevel::kDebug) << std::move(msg);
-            })
-            .build();
-
-    if (!client) {
-        LD_LOG(logger, LogLevel::kError) << "Failed to build client";
+        std::cout << "Set environment variable STG_SDK_KEY to the sdk key";
         return 1;
     }
 
-    client->run();
-    ioc.run();
+    Client client(ConfigBuilder(key).Build().value(),
+                  ContextBuilder().kind("user", "ryan").build());
+
+    client.WaitForReadySync(std::chrono::seconds(30));
+
+    auto value = client.BoolVariation("my-boolean-flag", false);
+    LD_LOG(logger, LogLevel::kInfo) << "Value was: " << value;
 }

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

@@ -1,15 +1,22 @@
 #pragma once
 
 #include <boost/asio/io_context.hpp>
+
+#include <condition_variable>
 #include <cstdint>
 #include <memory>
 #include <optional>
 #include <thread>
+
 #include <tl/expected.hpp>
 #include "config/client.hpp"
 #include "context.hpp"
 #include "error.hpp"
 #include "events/event_processor.hpp"
+#include "launchdarkly/client_side/data_source.hpp"
+#include "launchdarkly/client_side/data_sources/detail/data_source_status_manager.hpp"
+#include "launchdarkly/client_side/flag_manager/detail/flag_manager.hpp"
+#include "launchdarkly/client_side/flag_manager/detail/flag_updater.hpp"
 #include "logger.hpp"
 #include "value.hpp"
 
@@ -41,16 +48,33 @@ class Client {
 
     Value JsonVariation(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);
     void TrackInternal(std::string event_name,
                        std::optional<Value> data,
                        std::optional<double> metric_value);
 
+    bool initialized_;
+    std::mutex init_mutex_;
+    std::condition_variable init_waiter_;
+
+    data_sources::detail::DataSourceStatusManager status_manager_;
+    flag_manager::detail::FlagManager flag_manager_;
+    flag_manager::detail::FlagUpdater flag_updater_;
+
     Logger logger_;
     std::thread thread_;
     boost::asio::io_context ioc_;
     Context context_;
     std::unique_ptr<events::IEventProcessor> event_processor_;
+    std::unique_ptr<IDataSource> data_source_;
+    std::thread run_thread_;
 };
 
 }  // namespace launchdarkly::client_side

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

@@ -0,0 +1,27 @@
+#pragma once
+
+namespace launchdarkly::client_side {
+// TODO: Can be moved to common.
+
+/**
+ * Represents the connection of a listener.
+ * Disconnecting the connection will cause the listener to stop receiving
+ * events.
+ */
+class IConnection {
+   public:
+    /**
+     * Disconnect the listener and stop receiving events.
+     */
+    virtual void Disconnect() = 0;
+
+    virtual ~IConnection() = default;
+    IConnection(IConnection const& item) = delete;
+    IConnection(IConnection&& item) = delete;
+    IConnection& operator=(IConnection const&) = delete;
+    IConnection& operator=(IConnection&&) = delete;
+
+   protected:
+    IConnection() = default;
+};
+}  // namespace launchdarkly::client_side

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

@@ -4,8 +4,8 @@ namespace launchdarkly::client_side {
 
 class IDataSource {
    public:
-    virtual void start() = 0;
-    virtual void close() = 0;
+    virtual void Start() = 0;
+    virtual void Close() = 0;
 
     virtual ~IDataSource() = default;
     IDataSource(IDataSource const& item) = delete;

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

@@ -8,6 +8,7 @@
 #include "config/detail/built/service_endpoints.hpp"
 #include "context.hpp"
 #include "data/evaluation_result.hpp"
+#include "launchdarkly/client_side/data_sources/data_source_status.hpp"
 
 namespace launchdarkly::client_side {
 
@@ -48,9 +49,6 @@ class IDataSourceUpdateSink {
     virtual void Init(std::unordered_map<std::string, ItemDescriptor> data) = 0;
     virtual void Upsert(std::string key, ItemDescriptor item) = 0;
 
-    // We could add this if we want to support data source status.
-    // virtual void status(<something>)
-
     IDataSourceUpdateSink(IDataSourceUpdateSink const& item) = delete;
     IDataSourceUpdateSink(IDataSourceUpdateSink&& item) = delete;
     IDataSourceUpdateSink& operator=(IDataSourceUpdateSink const&) = delete;