Unleash Client SDK for C++

This repository provides a C++ client SDK for Unleash that meets the Unleash Client Specifications.

Features

The below table shows what features the SDKs support or plan to support.

• Feature toggles
• Built-in strategies
• Unleash context
• Strategy constrains
• Application registration
• Variants
• Custom stickiness (WIP)
• Bootstraping
• Usage Metrics

Requirements

• Compatible C++17 compiler such as Clang or GCC. The minimum required versions are Clang 4 and g++7.

Usage

Include Unleash library

#include <unleash/unleashclient.h>

Initialization

The unleashClient can be initialized with the following parameters but only appName and unleashServerUrl are mandatories.

Config	Required?	Type	Default value
Unleash URL	Yes	String	N/A
App. Name	Yes	String	N/A
Instance ID.	No	String	N/A
Environment	No	String	N/A
Authentication	No	String	N/A
Refresh Interval (ms)	No	Int	15000
Registration	No	Bool	False

unleash::UnleashClient unleashClient = unleash::UnleashClient::create("appName", "unleashServerUrl").instanceId("intanceId").environment("environment").authentication("token").refreshInterval(pollingTime).registration(boolValue);
unleashClient.initializeClient();

Feature Flag is enabled?

• Simple toggle:

unleashClient.isEnabled("feature.toogle");

• Toggle with context:

    #include "unleash/context.h"
    ...
    unleash::Context context{"userId", "sessionId", "remoteAddress"}
    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 featureEnabled;
      std::string payload;
    }
    */

For more information about variants, see the Variant documentation.

Integration

Building with CMake

The following requirements need to be installed to build the library using CMake:

• CMake 3.19+
• Conan 2 (CMakeDeps Generator)

By default, it provides the static library. The shared version shall be available using the CMake option BUILD_SHARED_LIB=YES.

The installation files include the UnleashConfig.cmake to integrate this library using the target unleash::unleash.

To build unleash client with conan and CMake run the following commands:

conan install . --output-folder=build --build=missing --settings=build_type=Debug
cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DCMAKE_PREFIX_PATH=$(pwd)/build
cmake --build build

Substitute Debug for Release to build the release version. The CMAKE_PREFIX_PATH and --output-folder parameters should point to the same directory, make sure to use an absolute path for the CMAKE_PREFIX_PATH.

Conan

This package is published in Conan Center as unleash-client-cpp/1.1.1.

Tested services

• Gitlab using application name and instance id parameters for authentication.
• Self-hosted unleash using client token for authentication.

Used third-party tools

Thanks a lot to the following tools for your contribution:

• Building a Dual Shared and Static Library with CMake for the CMake library template.
• C++ Requests: Curl for People for the API client library.
• JSON for Modern C++ for the JSON handling library.
• Codecov for code coverage solution.
• Sonarcloud for the static code analysis.
• CMake for the C++ build system.
• Conan.io for the C++ package manager.
• GitHub for the repository and CI/CD services.
• GoogleTest for C++ testing.