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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/affiliations/core/browser/affiliation_fetch_throttler.h"
#include <stdint.h>
#include <optional>
#include "base/check_op.h"
#include "base/containers/fixed_flat_set.h"
#include "base/functional/bind.h"
#include "base/rand_util.h"
#include "base/task/sequenced_task_runner.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "components/affiliations/core/browser/affiliation_fetch_throttler_delegate.h"
#include "net/base/net_errors.h"
#include "net/http/http_status_code.h"
namespace affiliations {
namespace {
constexpr auto kRetryableHttpErrors =
base::MakeFixedFlatSet<net::HttpStatusCode>(
{net::HTTP_INTERNAL_SERVER_ERROR, net::HTTP_BAD_GATEWAY,
net::HTTP_SERVICE_UNAVAILABLE, net::HTTP_GATEWAY_TIMEOUT,
net::HTTP_INSUFFICIENT_STORAGE,
net::HTTP_NETWORK_AUTHENTICATION_REQUIRED});
// Checks if the response code belongs to |kRetryableHttpErrors|.
// Empty |response_code_optional| is treated as a retryable error.
bool IsHttpErrorNonRetryable(
std::optional<net::HttpStatusCode> response_code_optional) {
return response_code_optional
? !base::Contains(kRetryableHttpErrors,
response_code_optional.value())
: false;
}
} // namespace
// static
const net::BackoffEntry::Policy AffiliationFetchThrottler::kBackoffPolicy = {
// Number of initial errors (in sequence) to ignore before going into
// exponential backoff.
0,
// Initial delay (in ms) once backoff starts.
10 * 1000, // 10 seconds
// Factor by which the delay will be multiplied on each subsequent failure.
4,
// Fuzzing percentage: 50% will spread delays randomly between 50%--100% of
// the nominal time.
.5, // 50%
// Maximum delay (in ms) during exponential backoff.
6 * 3600 * 1000, // 6 hours
// Time to keep an entry from being discarded even when it has no
// significant state, -1 to never discard. (Not applicable.)
-1,
// False means that initial_delay_ms is the first delay once we start
// exponential backoff, i.e., there is no delay after subsequent successful
// requests.
false,
};
// static
const int64_t AffiliationFetchThrottler::kGracePeriodAfterReconnectMs =
10 * 1000; // 10 seconds
// static
const int64_t AffiliationFetchThrottler::kBackoffAfterNonRetryableErrorHours =
3;
AffiliationFetchThrottler::AffiliationFetchThrottler(
AffiliationFetchThrottlerDelegate* delegate,
const scoped_refptr<base::SequencedTaskRunner>& task_runner,
network::NetworkConnectionTracker* network_connection_tracker,
const base::TickClock* tick_clock)
: delegate_(delegate),
task_runner_(task_runner),
network_connection_tracker_(network_connection_tracker),
tick_clock_(tick_clock),
state_(IDLE),
has_network_connectivity_(false),
is_fetch_scheduled_(false),
exponential_backoff_(
new net::BackoffEntry(&kBackoffPolicy, tick_clock_)) {
DCHECK(delegate);
// Start observing before querying the current connectivity state, so that if
// the state changes concurrently in-between, it will not go unnoticed.
network_connection_tracker_->AddNetworkConnectionObserver(this);
}
AffiliationFetchThrottler::~AffiliationFetchThrottler() {
network_connection_tracker_->RemoveNetworkConnectionObserver(this);
}
void AffiliationFetchThrottler::SignalNetworkRequestNeeded() {
if (state_ != IDLE)
return;
state_ = FETCH_NEEDED;
has_network_connectivity_ = !network_connection_tracker_->IsOffline();
if (has_network_connectivity_)
EnsureCallbackIsScheduled();
}
void AffiliationFetchThrottler::InformOfNetworkRequestComplete(
bool success,
std::optional<net::HttpStatusCode> http_status_code_optional) {
DCHECK_EQ(state_, FETCH_IN_FLIGHT);
state_ = IDLE;
exponential_backoff_->InformOfRequest(success);
if (!success && IsHttpErrorNonRetryable(http_status_code_optional)) {
exponential_backoff_->SetCustomReleaseTime(
std::max(exponential_backoff_->GetReleaseTime(),
tick_clock_->NowTicks() +
base::Hours(kBackoffAfterNonRetryableErrorHours)));
}
}
bool AffiliationFetchThrottler::HasInternetConnection() const {
return !network_connection_tracker_->IsOffline();
}
void AffiliationFetchThrottler::EnsureCallbackIsScheduled() {
DCHECK_EQ(state_, FETCH_NEEDED);
DCHECK(has_network_connectivity_);
if (is_fetch_scheduled_)
return;
is_fetch_scheduled_ = true;
task_runner_->PostDelayedTask(
FROM_HERE,
base::BindOnce(&AffiliationFetchThrottler::OnBackoffDelayExpiredCallback,
weak_ptr_factory_.GetWeakPtr()),
exponential_backoff_->GetTimeUntilRelease());
}
void AffiliationFetchThrottler::OnBackoffDelayExpiredCallback() {
DCHECK_EQ(state_, FETCH_NEEDED);
DCHECK(is_fetch_scheduled_);
is_fetch_scheduled_ = false;
// Do nothing if network connectivity was lost while this callback was in the
// task queue. The callback will be posted in the OnNetworkChanged
// handler once again.
if (!has_network_connectivity_)
return;
// The release time might have been increased if network connectivity was lost
// and restored while this callback was in the task queue. If so, reschedule.
if (exponential_backoff_->ShouldRejectRequest()) {
EnsureCallbackIsScheduled();
} else {
state_ = delegate_->OnCanSendNetworkRequest() ? FETCH_IN_FLIGHT : IDLE;
}
}
void AffiliationFetchThrottler::OnConnectionChanged(
network::mojom::ConnectionType type) {
bool old_has_network_connectivity = has_network_connectivity_;
// We reread the connection type here instead of relying on |type| because
// NetworkConnectionTracker will call this function an extra time with
// CONNECTION_NONE whenever the connection changes to an online state, even
// if it was already in a different online state.
has_network_connectivity_ = !network_connection_tracker_->IsOffline();
// Only react when network connectivity has been reestablished.
if (!has_network_connectivity_ || old_has_network_connectivity)
return;
double grace_ms = kGracePeriodAfterReconnectMs *
(1 - base::RandDouble() * kBackoffPolicy.jitter_factor);
exponential_backoff_->SetCustomReleaseTime(
std::max(exponential_backoff_->GetReleaseTime(),
tick_clock_->NowTicks() + base::Milliseconds(grace_ms)));
if (state_ == FETCH_NEEDED)
EnsureCallbackIsScheduled();
}
} // namespace affiliations
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