graceful_degradation_example.cpp File Reference

Demonstration of reliability patterns and graceful degradation. More...

#include <atomic>
#include <chrono>
#include <iostream>
#include <random>
#include <thread>
#include "kcenon/monitoring/core/error_codes.h"
#include "kcenon/monitoring/core/result_types.h"
#include "kcenon/monitoring/reliability/circuit_breaker.h"
#include "kcenon/monitoring/reliability/fault_tolerance_manager.h"
#include "kcenon/monitoring/reliability/retry_policy.h"

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Classes
class	unreliable_service

Functions
void	demonstrate_circuit_breaker ()
void	demonstrate_retry_policy ()
void	demonstrate_combined_patterns ()
int	main ()

Detailed Description

Demonstration of reliability patterns and graceful degradation.

Definition in file graceful_degradation_example.cpp.

Function Documentation

demonstrate_circuit_breaker()

void demonstrate_circuit_breaker

(

)

Examples

graceful_degradation_example.cpp, and health_reliability_example.cpp.

Definition at line 68 of file graceful_degradation_example.cpp.

                                   {
    std::cout << "=== Circuit Breaker Pattern ===" << std::endl;
    std::cout << std::endl;
 
    unreliable_service service(0.7);  // 70% failure rate
 
    circuit_breaker_config config;
    config.failure_threshold = 3;
    config.timeout = 5000ms;
 
    circuit_breaker breaker(config);
 
    std::cout << "Circuit Breaker Configuration:" << std::endl;
    std::cout << "- Failure threshold: " << config.failure_threshold << std::endl;
    std::cout << "- Reset timeout: 5000ms" << std::endl;
    std::cout << std::endl;
 
    std::cout << "Making calls to unreliable service (70% failure rate):" << std::endl;
    std::cout << std::endl;
 
    for (int i = 0; i < 10; ++i) {
        std::cout << "Call " << (i + 1) << ": ";
 
        auto result = execute_with_circuit_breaker<std::string>(breaker, "external_service", [&service]() {
            return service.call();
        });
 
        if (result.is_ok()) {
            std::cout << "SUCCESS" << std::endl;
        } else {
            std::cout << "FAILED" << std::endl;
        }
 
        std::this_thread::sleep_for(200ms);
    }
 
    std::cout << std::endl;
 
    auto stats = breaker.get_stats();
    std::cout << "Circuit Breaker Stats:" << std::endl;
    for (const auto& [key, val] : stats) {
        std::visit([&key](const auto& v) {
            std::cout << "- " << key << ": " << v << std::endl;
        }, val);
    }
    std::cout << std::endl;
}

References kcenon::monitoring::execute_with_circuit_breaker(), and kcenon::monitoring::service.

Referenced by main().

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demonstrate_combined_patterns()

void demonstrate_combined_patterns

(

)

Examples

graceful_degradation_example.cpp.

Definition at line 166 of file graceful_degradation_example.cpp.

                                     {
    std::cout << "=== Combined Reliability Patterns ===" << std::endl;
    std::cout << std::endl;
 
    unreliable_service primary_service(0.5);
 
    circuit_breaker_config cb_config;
    cb_config.failure_threshold = 3;
    circuit_breaker breaker(cb_config);
 
    retry_config retry_cfg2;
    retry_cfg2.max_attempts = 3;
    retry_cfg2.strategy = retry_strategy::exponential_backoff;
    retry_cfg2.initial_delay = 100ms;
 
    retry_executor<std::string> policy2("combined_retry", retry_cfg2);
 
    std::cout << "Combining Circuit Breaker + Retry Policy" << std::endl;
    std::cout << std::endl;
 
    for (int i = 0; i < 10; ++i) {
        std::cout << "Request " << (i + 1) << ": ";
 
        auto result = execute_with_circuit_breaker<std::string>(breaker, "primary", [&]() {
            return policy2.execute([&]() {
                return primary_service.call();
            });
        });
 
        if (result.is_ok()) {
            std::cout << "SUCCESS" << std::endl;
        } else {
            std::cout << "FAILED" << std::endl;
        }
 
        std::this_thread::sleep_for(300ms);
    }
 
    std::cout << std::endl;
 
    auto cb_stats = breaker.get_stats();
    std::cout << "Circuit Breaker Stats:" << std::endl;
    for (const auto& [key, val] : cb_stats) {
        std::visit([&key](const auto& v) {
            std::cout << "- " << key << ": " << v << std::endl;
        }, val);
    }
    std::cout << std::endl;
 
    auto retry_metrics = policy2.get_metrics();
    std::cout << "Retry Policy:" << std::endl;
    std::cout << "- Total executions: " << retry_metrics.total_executions << std::endl;
    std::cout << "- Total retries: " << retry_metrics.total_retries << std::endl;
    std::cout << std::endl;
}

References unreliable_service::call(), kcenon::monitoring::retry_executor< T >::execute(), kcenon::monitoring::execute_with_circuit_breaker(), kcenon::monitoring::retry_executor< T >::get_metrics(), kcenon::monitoring::retry_config::initial_delay, kcenon::monitoring::retry_config::max_attempts, kcenon::monitoring::retry_config::strategy, kcenon::monitoring::retry_metrics::total_executions, and kcenon::monitoring::retry_metrics::total_retries.

Referenced by main().

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demonstrate_retry_policy()

void demonstrate_retry_policy

(

)

Examples

graceful_degradation_example.cpp, and health_reliability_example.cpp.

Definition at line 117 of file graceful_degradation_example.cpp.

                                {
    std::cout << "=== Retry Policy with Exponential Backoff ===" << std::endl;
    std::cout << std::endl;
 
    unreliable_service service(0.4);  // 40% failure rate
 
    retry_config retry_cfg;
    retry_cfg.max_attempts = 5;
    retry_cfg.strategy = retry_strategy::exponential_backoff;
    retry_cfg.initial_delay = 100ms;
    retry_cfg.backoff_multiplier = 2.0;
 
    retry_executor<std::string> policy("service_retry", retry_cfg);
 
    std::cout << "Retry Policy Configuration:" << std::endl;
    std::cout << "- Strategy: Exponential backoff" << std::endl;
    std::cout << "- Max attempts: 5" << std::endl;
    std::cout << "- Initial delay: 100ms" << std::endl;
    std::cout << std::endl;
 
    std::cout << "Making calls with retry policy:" << std::endl;
    std::cout << std::endl;
 
    for (int i = 0; i < 5; ++i) {
        std::cout << "Request " << (i + 1) << ": ";
 
        auto result = policy.execute([&service]() {
            return service.call();
        });
 
        if (result.is_ok()) {
            std::cout << "SUCCESS" << std::endl;
        } else {
            std::cout << "FAILED after retries" << std::endl;
        }
    }
 
    std::cout << std::endl;
 
    auto metrics = policy.get_metrics();
    std::cout << "Retry Policy Metrics:" << std::endl;
    std::cout << "- Total executions: " << metrics.total_executions << std::endl;
    std::cout << "- Successful: " << metrics.successful_executions << std::endl;
    std::cout << "- Failed: " << metrics.failed_executions << std::endl;
    std::cout << "- Total retries: " << metrics.total_retries << std::endl;
    std::cout << std::endl;
}

References kcenon::monitoring::retry_config::backoff_multiplier, kcenon::monitoring::retry_executor< T >::execute(), kcenon::monitoring::retry_executor< T >::get_metrics(), kcenon::monitoring::retry_config::initial_delay, kcenon::monitoring::retry_config::max_attempts, kcenon::monitoring::service, kcenon::monitoring::retry_config::strategy, and kcenon::monitoring::retry_metrics::total_executions.

Referenced by main().

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main()

int main

(

)

Definition at line 222 of file graceful_degradation_example.cpp.

           {
    std::cout << "=== Graceful Degradation and Reliability Patterns ===" << std::endl;
    std::cout << std::endl;
 
    try {
        demonstrate_circuit_breaker();
        std::cout << std::string(70, '=') << std::endl;
        std::cout << std::endl;
 
        demonstrate_retry_policy();
        std::cout << std::string(70, '=') << std::endl;
        std::cout << std::endl;
 
        demonstrate_combined_patterns();
        std::cout << std::string(70, '=') << std::endl;
        std::cout << std::endl;
 
        std::cout << "=== All Reliability Patterns Demonstrated Successfully ===" << std::endl;
 
    } catch (const std::exception& e) {
        std::cerr << "Exception: " << e.what() << std::endl;
        return 1;
    }
 
    return 0;
}

References demonstrate_circuit_breaker(), demonstrate_combined_patterns(), and demonstrate_retry_policy().

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