This is your first hands-on lesson with the C++ SDK: create a client, send an event, and receive it. Make sure you have the SDK installed (see the C++ SDK overview).

Create a Client

main.cc

#include <iostream>
#include "kubemq/kubemq.h"

int main() {
    kubemq::ClientOptions opts;
    opts.set_address("localhost", 50000);
    opts.set_client_id("my-app");

    auto client_or = kubemq::Client::Create(opts);
    if (!client_or.ok()) {
        std::cerr << "Connect failed: " << client_or.status().ToString() << "\n";
        return 1;
    }
    auto& client = *client_or;

    auto ping_or = client->Ping();
    if (ping_or.ok()) {
        std::cout << "Connected to: " << ping_or->host
                  << " v" << ping_or->version << "\n";
    }

    auto close_status = client->Close();
    if (!close_status.ok()) {
        std::cerr << "Close failed: " << close_status.message() << "\n";
    }
    return 0;
}

Send Your First Event

send_event.cc

auto event_or = kubemq::Event::Builder()
    .SetChannel("notifications")
    .SetBody("hello kubemq")
    .SetMetadata("greeting")
    .Build();
if (!event_or.ok()) {
    std::cerr << "Build failed: " << event_or.status().ToString() << "\n";
    return 1;
}

auto status = client->SendEvent(*event_or);
if (!status.ok()) {
    std::cerr << "Send failed: " << status.ToString() << "\n";
}
std::cout << "Event sent successfully\n";

Receive Events

receive_events.cc

auto sub_or = client->SubscribeToEvents("notifications", "",
    [](const kubemq::EventReceive& event) {
        std::cout << "Received: " << event.body << "\n";
    },
    [](const kubemq::Status& err) {
        std::cerr << "Error: " << err.message() << "\n";
    });
if (!sub_or.ok()) {
    std::cerr << "Subscribe failed: " << sub_or.status().ToString() << "\n";
    return 1;
}
auto& sub = *sub_or;

// When done:
sub->Cancel();

Configuration Options

Option	Default	Description
`set_address(host, port)`	`localhost:50000`	KubeMQ server address
`set_client_id(id)`	Auto-generated UUID	Unique client identifier
`set_auth_token(token)`	None	JWT or API key authentication
`set_tls_config(config)`	None (plaintext)	TLS/mTLS configuration
`set_reconnect_policy(p)`	Infinite retries, backoff	Reconnection behavior
`set_connection_timeout(d)`	10s	Initial connection timeout
`set_retry_policy(p)`	Default retry	Retry for transient failures
`set_logger(l)`	None	Custom logger implementation
`set_tracer_provider(tp)`	None	OpenTelemetry tracer
`set_meter_provider(mp)`	None	OpenTelemetry meter

Error Handling

The C++ SDK uses Status and StatusOr<T> return types instead of exceptions. Always check ok() before accessing values:

auto result = client->SendEvent(event);
if (!result.ok()) {
    std::cerr << "Code: " << static_cast<int>(result.code())
              << " Message: " << result.message()
              << " Retryable: " << result.is_retryable() << "\n";

    switch (result.code()) {
    case kubemq::ErrorCode::kTimeout:
        // Retry with longer timeout
        break;
    case kubemq::ErrorCode::kAuthentication:
        // Check credentials
        break;
    case kubemq::ErrorCode::kTransient:
        // Automatic retry exhausted
        break;
    default:
        break;
    }
}

Next Steps

C++ SDK Reference -- full API documentation
C++ SDK Examples -- complete examples for all patterns
GitHub Repository -- source code and issues

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