config_example.cpp

Demonstrates nine configuration scenarios: defaults, builder basics, backpressure, circuit breaker, work stealing, priority aging, DAG scheduling, a production-ready combined config, and direct struct initialization.

See also

thread_system_config, thread_system_config::builder

// BSD 3-Clause License
// Copyright (c) 2024, 🍀☀🌕🌥 🌊
// See the LICENSE file in the project root for full license information.
 
#include <kcenon/thread/thread_config.h>
#include <iostream>
 
namespace
{
    void example_default_config()
    {
        std::cout << "\n=== Example 1: Default Configuration ===\n";
 
        kcenon::thread::thread_system_config config;
 
        std::cout << "Worker count: " << config.pool.worker_count << "\n";
        std::cout << "Queue capacity: " << config.pool.queue_capacity << "\n";
        std::cout << "Backpressure policy: "
                  << kcenon::thread::backpressure_policy_to_string(config.pool.backpressure.policy)
                  << "\n";
    }
 
    void example_builder_basic()
    {
        std::cout << "\n=== Example 2: Builder Pattern (Basic) ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(8)
                          .with_queue_capacity(5000)
                          .build();
 
        std::cout << "Worker count: " << config.pool.worker_count << "\n";
        std::cout << "Queue capacity: " << config.pool.queue_capacity << "\n";
        std::cout << "Configuration is valid: " << (config.is_valid() ? "yes" : "no") << "\n";
    }
 
    void example_backpressure_config()
    {
        std::cout << "\n=== Example 3: Backpressure Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(4)
                          .with_queue_capacity(1000)
                          .enable_backpressure()
                          .with_backpressure_policy(kcenon::thread::backpressure_policy::adaptive)
                          .with_watermarks(0.5, 0.8)
                          .build();
 
        std::cout << "Backpressure enabled: yes\n";
        std::cout << "Policy: "
                  << kcenon::thread::backpressure_policy_to_string(config.pool.backpressure.policy)
                  << "\n";
        std::cout << "Low watermark: " << config.pool.backpressure.low_watermark << "\n";
        std::cout << "High watermark: " << config.pool.backpressure.high_watermark << "\n";
    }
 
    void example_circuit_breaker_config()
    {
        std::cout << "\n=== Example 4: Circuit Breaker Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(4)
                          .enable_circuit_breaker()
                          .with_failure_threshold(5)
                          .with_open_duration(std::chrono::seconds{30})
                          .build();
 
        std::cout << "Circuit breaker enabled: yes\n";
        std::cout << "Failure threshold: "
                  << config.resilience.circuit_breaker.failure_threshold << "\n";
        std::cout << "Open duration: "
                  << config.resilience.circuit_breaker.timeout.count() << "s\n";
        std::cout << "Half-open max requests: "
                  << config.resilience.circuit_breaker.half_open_max_requests << "\n";
    }
 
    void example_work_stealing_config()
    {
        std::cout << "\n=== Example 5: Work Stealing Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(8)
                          .enable_work_stealing()
                          .with_work_stealing_params(3, std::chrono::microseconds{50})
                          .build();
 
        std::cout << "Work stealing enabled: " << (config.pool.enable_work_stealing ? "yes" : "no")
                  << "\n";
        std::cout << "Max steal attempts: " << config.pool.max_steal_attempts << "\n";
        std::cout << "Steal backoff: " << config.pool.steal_backoff.count() << "μs\n";
    }
 
    void example_priority_aging_config()
    {
        std::cout << "\n=== Example 6: Priority Aging Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(4)
                          .enable_priority_aging()
                          .with_priority_aging_params(std::chrono::seconds{1}, 1, 3)
                          .build();
 
        std::cout << "Priority aging enabled: "
                  << (config.scaling.priority_aging.enabled ? "yes" : "no") << "\n";
        std::cout << "Aging interval: " << config.scaling.priority_aging.aging_interval.count()
                  << "ms\n";
        std::cout << "Boost per interval: "
                  << config.scaling.priority_aging.priority_boost_per_interval << "\n";
        std::cout << "Max boost: " << config.scaling.priority_aging.max_priority_boost << "\n";
    }
 
    void example_dag_config()
    {
        std::cout << "\n=== Example 7: DAG Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(4)
                          .with_dag_failure_policy(kcenon::thread::dag_failure_policy::retry)
                          .with_dag_retry_params(3, std::chrono::milliseconds{1000})
                          .build();
 
        std::cout << "DAG failure policy: "
                  << kcenon::thread::dag_failure_policy_to_string(config.dag.failure_policy)
                  << "\n";
        std::cout << "Max retries: " << config.dag.max_retries << "\n";
        std::cout << "Retry delay: " << config.dag.retry_delay.count() << "ms\n";
        std::cout << "Detect cycles: " << (config.dag.detect_cycles ? "yes" : "no") << "\n";
        std::cout << "Execute in parallel: " << (config.dag.execute_in_parallel ? "yes" : "no")
                  << "\n";
    }
 
    void example_production_config()
    {
        std::cout << "\n=== Example 8: Production Configuration ===\n";
 
        auto config = kcenon::thread::thread_system_config::builder()
                          .with_worker_count(std::thread::hardware_concurrency())
                          .with_queue_capacity(10000)
                          .enable_backpressure()
                          .with_backpressure_policy(kcenon::thread::backpressure_policy::adaptive)
                          .with_watermarks(0.6, 0.85)
                          .enable_circuit_breaker()
                          .with_failure_threshold(10)
                          .with_open_duration(std::chrono::seconds{60})
                          .enable_work_stealing()
                          .with_work_stealing_params(5, std::chrono::microseconds{100})
                          .enable_priority_aging()
                          .with_priority_aging_params(std::chrono::seconds{2}, 1, 5)
                          .with_dag_failure_policy(kcenon::thread::dag_failure_policy::continue_others)
                          .build();
 
        std::cout << "Worker count: " << config.pool.worker_count << "\n";
        std::cout << "Queue capacity: " << config.pool.queue_capacity << "\n";
        std::cout << "Backpressure: adaptive (low=" << config.pool.backpressure.low_watermark
                  << ", high=" << config.pool.backpressure.high_watermark << ")\n";
        std::cout << "Circuit breaker: threshold=" << config.resilience.circuit_breaker.failure_threshold
                  << ", open_duration=" << config.resilience.circuit_breaker.timeout.count()
                  << "s\n";
        std::cout << "Work stealing: enabled, max_attempts=" << config.pool.max_steal_attempts
                  << "\n";
        std::cout << "Priority aging: enabled, interval="
                  << config.scaling.priority_aging.aging_interval.count() << "ms\n";
        std::cout << "DAG failure policy: "
                  << kcenon::thread::dag_failure_policy_to_string(config.dag.failure_policy)
                  << "\n";
        std::cout << "Configuration is valid: " << (config.is_valid() ? "yes" : "no") << "\n";
    }
 
    void example_direct_initialization()
    {
        std::cout << "\n=== Example 9: Direct Initialization ===\n";
 
        kcenon::thread::thread_system_config config;
        config.pool.worker_count = 6;
        config.pool.queue_capacity = 2000;
        config.pool.backpressure.policy = kcenon::thread::backpressure_policy::drop_oldest;
        config.resilience.circuit_breaker.failure_threshold = 3;
        config.scaling.priority_aging.enabled = true;
 
        std::cout << "Worker count: " << config.pool.worker_count << "\n";
        std::cout << "Queue capacity: " << config.pool.queue_capacity << "\n";
        std::cout << "Backpressure policy: "
                  << kcenon::thread::backpressure_policy_to_string(config.pool.backpressure.policy)
                  << "\n";
        std::cout << "Circuit breaker threshold: "
                  << config.resilience.circuit_breaker.failure_threshold << "\n";
        std::cout << "Priority aging enabled: "
                  << (config.scaling.priority_aging.enabled ? "yes" : "no") << "\n";
    }
} // namespace
 
int main()
{
    std::cout << "========================================\n";
    std::cout << "Thread System Configuration Examples\n";
    std::cout << "========================================\n";
 
    example_default_config();
    example_builder_basic();
    example_backpressure_config();
    example_circuit_breaker_config();
    example_work_stealing_config();
    example_priority_aging_config();
    example_dag_config();
    example_production_config();
    example_direct_initialization();
 
    std::cout << "\n========================================\n";
    std::cout << "All examples completed successfully!\n";
    std::cout << "========================================\n";
 
    return 0;
}