Coverage Report

Created: 2026-08-02 08:38

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
common/cpp/token_bucket_rate_limiter.cpp
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// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements.  See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership.  The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License.  You may obtain a copy of the License at
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//
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//   http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied.  See the License for the
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// specific language governing permissions and limitations
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// under the License.
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#include "token_bucket_rate_limiter.h"
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#include <bthread/bthread.h>
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#include <glog/logging.h> // IWYU pragma: export
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#include <atomic>
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#include <chrono>
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#include <mutex>
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#include <thread>
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#if defined(__APPLE__)
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#include <ctime>
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#endif
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namespace doris {
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// Just 10^6.
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static constexpr auto NS = 1000000000UL;
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bvar::Adder<int64_t> s3_get_rate_limit_sleep_ns("s3_get_rate_limit_sleep_ns");
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bvar::Adder<int64_t> s3_get_rate_limit_sleep_count("s3_get_rate_limit_sleep_count");
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bvar::Adder<int64_t> s3_get_rate_limit_rejected_count("s3_get_rate_limit_rejected_count");
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bvar::Adder<int64_t> s3_put_rate_limit_sleep_ns("s3_put_rate_limit_sleep_ns");
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bvar::Adder<int64_t> s3_put_rate_limit_sleep_count("s3_put_rate_limit_sleep_count");
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bvar::Adder<int64_t> s3_put_rate_limit_rejected_count("s3_put_rate_limit_rejected_count");
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static std::atomic<int64_t> s3_get_rate_limit_sleep_log_count {0};
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static std::atomic<int64_t> s3_get_rate_limit_rejected_log_count {0};
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static std::atomic<int64_t> s3_put_rate_limit_sleep_log_count {0};
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static std::atomic<int64_t> s3_put_rate_limit_rejected_log_count {0};
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class TokenBucketRateLimiter::SimpleSpinLock {
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public:
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    SimpleSpinLock() = default;
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    ~SimpleSpinLock() = default;
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    void lock() {
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        int spin_count = 0;
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        static constexpr int MAX_SPIN_COUNT = 50;
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        while (_flag.test_and_set(std::memory_order_acq_rel)) {
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            spin_count++;
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            if (spin_count >= MAX_SPIN_COUNT) {
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                LOG(WARNING) << "Warning: Excessive spinning detected while acquiring lock. Spin "
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                                "count: "
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                             << spin_count;
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                spin_count = 0;
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            }
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            // Spin until we acquire the lock
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        }
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    }
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    void unlock() { _flag.clear(std::memory_order_release); }
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private:
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    std::atomic_flag _flag = ATOMIC_FLAG_INIT;
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};
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TokenBucketRateLimiter::TokenBucketRateLimiter(size_t max_speed, size_t max_burst, size_t limit)
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        : _max_speed(max_speed),
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          _max_burst(max_burst),
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          _limit(limit),
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          _mutex(std::make_unique<TokenBucketRateLimiter::SimpleSpinLock>()),
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          _remain_tokens(max_burst) {}
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TokenBucketRateLimiter::~TokenBucketRateLimiter() = default;
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TokenBucketRateLimiterHolder::~TokenBucketRateLimiterHolder() = default;
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std::pair<size_t, double> TokenBucketRateLimiter::_update_remain_token(long now, size_t amount) {
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    // Values obtained under lock to be checked after release
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    size_t count_value;
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    double tokens_value;
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    {
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        std::lock_guard<SimpleSpinLock> lock(*_mutex);
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        now = (now < _prev_ns_count) ? _prev_ns_count : now;
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        if (_max_speed) {
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            double delta_seconds =
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                    _prev_ns_count ? static_cast<double>(now - _prev_ns_count) / NS : 0;
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            _remain_tokens = std::min<double>(_remain_tokens + _max_speed * delta_seconds - amount,
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                                              _max_burst);
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        }
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        _count += amount;
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        count_value = _count;
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        if (_limit && count_value > _limit) {
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            // Keep rejection side-effect free. Roll back before releasing the lock so
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            // concurrent callers cannot observe debt from a request that will not run.
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            _count -= amount;
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            if (_max_speed) {
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                _remain_tokens = std::min<double>(_remain_tokens + amount, _max_burst);
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            }
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        }
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        tokens_value = _remain_tokens;
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        _prev_ns_count = now;
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    }
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    return {count_value, tokens_value};
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}
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int64_t TokenBucketRateLimiter::add(size_t amount) {
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    // Values obtained under lock to be checked after release
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    auto duration = std::chrono::steady_clock::now().time_since_epoch();
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    auto time_nano_count = std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count();
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    auto [count_value, tokens_value] = _update_remain_token(time_nano_count, amount);
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    if (_limit && count_value > _limit) {
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        // CK would throw exception
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        return -1;
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    }
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    // Wait unless there is positive amount of remain_tokens - throttling
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    int64_t sleep_time_ns = 0;
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    if (_max_speed && tokens_value < 0) {
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        sleep_time_ns = static_cast<int64_t>(-tokens_value / _max_speed * NS);
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        bthread_usleep(sleep_time_ns / 1000);
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    }
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    return sleep_time_ns;
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}
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void TokenBucketRateLimiter::refund(size_t amount) {
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    std::lock_guard<SimpleSpinLock> lock(*_mutex);
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    if (_max_speed) {
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        _remain_tokens = std::min<double>(_remain_tokens + amount, _max_burst);
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    }
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    _count = (_count >= amount) ? _count - amount : 0;
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}
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TokenBucketRateLimiterHolder::TokenBucketRateLimiterHolder(size_t max_speed, size_t max_burst,
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                                                           size_t limit,
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                                                           std::function<void(int64_t)> metric_func)
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        : rate_limiter(std::make_shared<TokenBucketRateLimiter>(max_speed, max_burst, limit)),
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          _enabled(max_speed > 0 || limit > 0),
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          metric_func(std::move(metric_func)) {}
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int64_t TokenBucketRateLimiterHolder::add(size_t amount) {
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    return add_with_config(amount).sleep_duration;
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}
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TokenBucketRateLimiterResult TokenBucketRateLimiterHolder::add_with_config(size_t amount) {
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    // Snapshot the current limiter and call add() outside the read lock: add() may
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    // sleep for a long time when throttled, and holding the read lock across the
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    // sleep would block reset() (dynamic config update) for the whole duration.
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    std::shared_ptr<TokenBucketRateLimiter> limiter;
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    {
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        std::shared_lock read {rate_limiter_rw_lock};
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        limiter = rate_limiter;
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    }
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    TokenBucketRateLimiterResult result = {.sleep_duration = limiter->add(amount),
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                                           .max_speed = limiter->get_max_speed(),
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                                           .max_burst = limiter->get_max_burst(),
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                                           .limit = limiter->get_limit()};
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    metric_func(result.sleep_duration);
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    return result;
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}
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std::shared_ptr<TokenBucketRateLimiter> TokenBucketRateLimiterHolder::charge(size_t amount) {
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    std::shared_ptr<TokenBucketRateLimiter> limiter;
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    {
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        std::shared_lock read {rate_limiter_rw_lock};
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        limiter = rate_limiter;
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    }
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    int64_t sleep_duration = limiter->add(amount);
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    metric_func(sleep_duration);
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    return sleep_duration < 0 ? nullptr : limiter;
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}
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int TokenBucketRateLimiterHolder::reset(size_t max_speed, size_t max_burst, size_t limit) {
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    auto new_rate_limiter = std::make_shared<TokenBucketRateLimiter>(max_speed, max_burst, limit);
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    {
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        std::unique_lock write {rate_limiter_rw_lock};
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        rate_limiter = std::move(new_rate_limiter);
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        _enabled.store(max_speed > 0 || limit > 0, std::memory_order_release);
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    }
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    return 0;
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}
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size_t TokenBucketRateLimiterHolder::get_max_speed() const {
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    std::shared_lock read {rate_limiter_rw_lock};
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    return rate_limiter->get_max_speed();
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}
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size_t TokenBucketRateLimiterHolder::get_max_burst() const {
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    std::shared_lock read {rate_limiter_rw_lock};
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    return rate_limiter->get_max_burst();
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}
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size_t TokenBucketRateLimiterHolder::get_limit() const {
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    std::shared_lock read {rate_limiter_rw_lock};
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    return rate_limiter->get_limit();
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}
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std::string to_string(S3RateLimitType type) {
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    switch (type) {
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    case S3RateLimitType::GET:
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        return "get";
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    case S3RateLimitType::PUT:
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        return "put";
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    default:
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        return std::to_string(static_cast<size_t>(type));
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    }
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}
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S3RateLimitType string_to_s3_rate_limit_type(std::string_view value) {
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    if (value == "get") {
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        return S3RateLimitType::GET;
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    } else if (value == "put") {
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        return S3RateLimitType::PUT;
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    }
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    return S3RateLimitType::UNKNOWN;
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}
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std::function<void(int64_t)> s3_rate_limiter_metric_func(S3RateLimitType type) {
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    switch (type) {
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    case S3RateLimitType::GET:
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        return metric_func_factory(s3_get_rate_limit_sleep_ns, s3_get_rate_limit_sleep_count,
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                                   &s3_get_rate_limit_rejected_count);
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    case S3RateLimitType::PUT:
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        return metric_func_factory(s3_put_rate_limit_sleep_ns, s3_put_rate_limit_sleep_count,
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                                   &s3_put_rate_limit_rejected_count);
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    default:
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        return [](int64_t) {};
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    }
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}
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int64_t apply_s3_rate_limit(S3RateLimitType type, S3RateLimiterHolder* rate_limiter,
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                            int64_t log_interval) {
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    auto result = rate_limiter->add_with_config(1);
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    auto sleep_duration = result.sleep_duration;
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    if (log_interval <= 0 || sleep_duration == 0) {
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        return sleep_duration;
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    }
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    auto is_get = type == S3RateLimitType::GET;
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    auto* sleep_log_count =
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            is_get ? &s3_get_rate_limit_sleep_log_count : &s3_put_rate_limit_sleep_log_count;
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    auto* rejected_log_count =
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            is_get ? &s3_get_rate_limit_rejected_log_count : &s3_put_rate_limit_rejected_log_count;
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    if (sleep_duration > 0) {
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        int64_t count = sleep_log_count->fetch_add(1, std::memory_order_relaxed) + 1;
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        if (count == 1 || count % log_interval == 0) {
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            LOG(INFO) << "S3 " << to_string(type) << " request is throttled by local rate limiter"
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                      << ", sleep_ms=" << sleep_duration / 1000000 << ", sleep_count=" << count
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                      << ", token_per_second=" << result.max_speed
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                      << ", bucket_tokens=" << result.max_burst << ", token_limit=" << result.limit;
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        }
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    } else {
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        int64_t count = rejected_log_count->fetch_add(1, std::memory_order_relaxed) + 1;
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        if (count == 1 || count % log_interval == 0) {
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            LOG(WARNING) << "S3 " << to_string(type) << " request is rejected by local rate limiter"
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                         << ", rejected_count=" << count
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                         << ", token_per_second=" << result.max_speed
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                         << ", bucket_tokens=" << result.max_burst
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                         << ", token_limit=" << result.limit;
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        }
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    }
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    return sleep_duration;
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}
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} // namespace doris