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| #ifndef RATE_LIMITER_H
#define RATE_LIMITER_H
#include "DataCollector.h"
#include "cmmlib/CmmBase.h"
#include <map>
#include <memory>
#include <chrono>
namespace RateLimitFramework {
class CMM_API RateLimitHandler {
public:
virtual void handle(const std::string& key, const std::map<std::string, std::string>& context) = 0;
virtual ~RateLimitHandler() = default;
};
class CMM_API RateLimiter {
private:
struct Strategy {
RateLimitStrategy config;
std::shared_ptr<DataCollector> dataCollector;
std::shared_ptr<RateLimitHandler> handler;
std::chrono::steady_clock::time_point lastExecutionTime;
double tokens;
Strategy(const RateLimitStrategy& cfg, std::shared_ptr<DataCollector> dc, std::shared_ptr<RateLimitHandler> rh)
: config(cfg), dataCollector(dc), handler(rh), lastExecutionTime(std::chrono::steady_clock::now()), tokens(cfg.threshold) {}
Strategy()
: config{}, dataCollector(nullptr), handler(nullptr), lastExecutionTime(std::chrono::steady_clock::now()), tokens(0.0) {}
};
std::map<StrategyType, Strategy> strategies;
public:
void addStrategy(const RateLimitStrategy& strategy, std::shared_ptr<DataCollector> dataCollector, std::shared_ptr<RateLimitHandler> handler);
bool checkLimit(StrategyType strategyType, const std::string& key);
private:
bool checkSimpleCounter(const Strategy& strategy, const std::string& key);
bool checkSlidingWindow(const Strategy& strategy, const std::string& key);
bool checkTokenBucket(Strategy& strategy, const std::string& key);
};
}
#endif
#include "cmmlib/ratelimit/RateLimit.h"
#include <map>
#include <algorithm>
using namespace std;
using namespace std::chrono;
using namespace RateLimitFramework;
namespace RateLimitFramework {
void RateLimiter::addStrategy(const RateLimitStrategy& strategy, shared_ptr<DataCollector> dataCollector, shared_ptr<RateLimitHandler> handler) {
strategies[strategy.strategyType] = Strategy(strategy, dataCollector, handler);
}
bool RateLimiter::checkLimit(StrategyType strategyType, const std::string& key) {
auto strategyIt = strategies.find(strategyType);
if (strategyIt == strategies.end()) {
return true;
}
auto& strategy = strategyIt->second;
strategy.dataCollector->record(key, strategy.config);
switch (strategy.config.algorithm) {
case RateLimitAlgorithm::SIMPLE_COUNTER:
return checkSimpleCounter(strategy, key);
case RateLimitAlgorithm::SLIDING_WINDOW:
return checkSlidingWindow(strategy, key);
case RateLimitAlgorithm::TOKEN_BUCKET:
return checkTokenBucket(strategy, key);
}
return true;
}
bool RateLimiter::checkSimpleCounter(const Strategy& strategy, const std::string& key) {
int count = strategy.dataCollector->getData(key, strategy.config);
if (count > strategy.config.threshold) {
std::map<std::string, std::string> context;
strategy.handler->handle(key, context);
return false;
}
return true;
}
bool RateLimiter::checkSlidingWindow(const Strategy& strategy, const std::string& key) {
int count = strategy.dataCollector->getData(key, strategy.config);
if (count > strategy.config.threshold) {
std::map<std::string, std::string> context;
strategy.handler->handle(key, context);
return false;
}
return true;
}
bool RateLimiter::checkTokenBucket(Strategy& strategy, const std::string& key) {
auto now = steady_clock::now();
auto timePassed = chrono::duration_cast<chrono::milliseconds>(now - strategy.lastExecutionTime).count();
strategy.tokens += timePassed * (strategy.config.threshold / static_cast<double>(strategy.config.timeWindow.count()));
strategy.tokens = (std::min)(strategy.tokens, static_cast<double>(strategy.config.threshold));
strategy.lastExecutionTime = now;
if (strategy.tokens < 1.0) {
std::map<std::string, std::string> context;
strategy.handler->handle(key, context);
return false;
}
else {
strategy.tokens -= 1.0;
return true;
}
}
}
|
