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