144 lines
3.8 KiB
C++
144 lines
3.8 KiB
C++
/*
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* nghttp2 - HTTP/2 C Library
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*
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* Copyright (c) 2014 Tatsuhiro Tsujikawa
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "shrpx_connect_blocker.h"
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#include "shrpx_config.h"
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#include "shrpx_log.h"
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namespace shrpx {
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namespace {
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void connect_blocker_cb(struct ev_loop *loop, ev_timer *w, int revents) {
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auto connect_blocker = static_cast<ConnectBlocker *>(w->data);
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "Unblock";
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}
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connect_blocker->call_unblock_func();
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}
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} // namespace
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ConnectBlocker::ConnectBlocker(std::mt19937 &gen, struct ev_loop *loop,
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std::function<void()> block_func,
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std::function<void()> unblock_func)
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: gen_(gen),
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block_func_(block_func),
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unblock_func_(unblock_func),
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loop_(loop),
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fail_count_(0),
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offline_(false) {
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ev_timer_init(&timer_, connect_blocker_cb, 0., 0.);
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timer_.data = this;
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}
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ConnectBlocker::~ConnectBlocker() { ev_timer_stop(loop_, &timer_); }
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bool ConnectBlocker::blocked() const { return ev_is_active(&timer_); }
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void ConnectBlocker::on_success() {
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if (ev_is_active(&timer_)) {
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return;
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}
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fail_count_ = 0;
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}
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// Use the similar backoff algorithm described in
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// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md
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namespace {
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constexpr size_t MAX_BACKOFF_EXP = 10;
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constexpr auto MULTIPLIER = 1.6;
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constexpr auto JITTER = 0.2;
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} // namespace
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void ConnectBlocker::on_failure() {
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if (ev_is_active(&timer_)) {
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return;
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}
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call_block_func();
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++fail_count_;
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auto base_backoff =
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util::int_pow(MULTIPLIER, std::min(MAX_BACKOFF_EXP, fail_count_));
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auto dist = std::uniform_real_distribution<>(-JITTER * base_backoff,
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JITTER * base_backoff);
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auto &downstreamconf = *get_config()->conn.downstream;
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auto backoff =
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std::min(downstreamconf.timeout.max_backoff, base_backoff + dist(gen_));
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LOG(WARN) << "Could not connect " << fail_count_
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<< " times in a row; sleep for " << backoff << " seconds";
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ev_timer_set(&timer_, backoff, 0.);
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ev_timer_start(loop_, &timer_);
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}
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size_t ConnectBlocker::get_fail_count() const { return fail_count_; }
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void ConnectBlocker::offline() {
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if (offline_) {
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return;
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}
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if (!ev_is_active(&timer_)) {
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call_block_func();
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}
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offline_ = true;
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ev_timer_stop(loop_, &timer_);
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ev_timer_set(&timer_, std::numeric_limits<double>::max(), 0.);
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ev_timer_start(loop_, &timer_);
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}
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void ConnectBlocker::online() {
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ev_timer_stop(loop_, &timer_);
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call_unblock_func();
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fail_count_ = 0;
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offline_ = false;
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}
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bool ConnectBlocker::in_offline() const { return offline_; }
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void ConnectBlocker::call_block_func() {
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if (block_func_) {
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block_func_();
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}
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}
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void ConnectBlocker::call_unblock_func() {
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if (unblock_func_) {
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unblock_func_();
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}
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}
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} // namespace shrpx
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