Add C++ binding library

[oleg-nenashev]

The current C API is quite complicated for consumption. It would be great to have a C++ binding with better developer experience for C/C++ users.

• Namespace
• Proper Structures
• TBD: Classes

Possible implementations

1. A single-header C++ library. The class structure can be inspired by the Rust or Java implementation. Java is a reference implementation, so the structure could be considered as a North Star for us

• Maybe: Java API export to C++ bindings boilerplate

2. Creating a new official Docker client for C++, and rebuilding a Testcontainers impl from Scrath => XXXXXL sized project
3. ? Connecting to another implementation over API

C++ Standard: TBD but something relatively recent

TODOs

• Define the approximate architecture of the API
• First PoC
• Include C/C++ binding into the distros and get a preview
• More tests and demos
• Update documentation

[miltoncs]

Big fan of test containers, I'm excited for the C++ library to be production ready!

[cppudge]

Hi, I wanted to use this library in my project, but I discovered that cgo has extremely poor cross-platform support, which is unsuitable for a public C++ library. So I decided to try a similar approach, but using rust, testcontainers-rs, and cxx, which have much better cross-platform support and CMake integration. I already have a project skeleton, and overall, C++ compatibility is quite good. The interface looks something like this::

TEST(RedisTest, StartAndGetMappedPort) {

  auto container = GenericImage("redis", "7.2")
                       .with_exposed_port(ContainerPort::Tcp(6379))
                       .with_wait_for(WaitFor::message_on_stdout("Ready to accept connections"))
                       .with_health_check(Healthcheck::Cmd({"redis-cli", "ping"}).with_interval(std::chrono::seconds(1)))
                       .start();

  auto host_port = container.get_host_port_ipv4(ContainerPort::Tcp(6379));

  EXPECT_GT(host_port, 0);
  std::cout << "Redis mapped port: " << host_port << std::endl;

  // Container will be auto-cleaned when it goes out of scope
}

[oleg-nenashev]

#54 from @seffradev gets us very close to completing it. Before the the release, we need to update the docs in https://testcontainers.github.io/testcontainers-native/docs/cpp/ , and to cleanup a few other examples. I will try to test the changes in the main over the next 1-2 weeks

[mplumleeUNH]

For what it's worth, I tried setting up to use TestContainers in a C++ project today, not realizing it's incomplete (Gemini hallucinated how to use it, apparently). I brought it in using CMake FetchContent, which led to the compiler error I put a PR in for. But now, looking at the Container and Builder interfaces, I don't see how I should wait-until or trigger-code-when the service is running in the container, nor how to get the endpoint to use in a call to a constructor for a Redis object. Are these things in the works? If so, how long do you think it might be before they are ready? If not, does someone have an example sitting around that you're testing with?

[oleg-nenashev]

The C++ lib definitely needs more work before we can call it ready (basically this whole repo is pre-1.0 and needs more work).

Thanks for the PR addressing some of the problems. We definitely need a smoke test and a demo for FetchContent so that it does not explode.