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/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "logging/rtc_event_log/rtc_event_log_impl.h"
#include <functional>
#include <limits>
#include <memory>
#include <utility>
#include <vector>
#include "absl/strings/string_view.h"
#include "api/environment/environment.h"
#include "api/field_trials_view.h"
#include "api/task_queue/task_queue_base.h"
#include "api/units/time_delta.h"
#include "logging/rtc_event_log/encoder/rtc_event_log_encoder_legacy.h"
#include "logging/rtc_event_log/encoder/rtc_event_log_encoder_new_format.h"
#include "rtc_base/checks.h"
#include "rtc_base/event.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_conversions.h"
#include "rtc_base/numerics/safe_minmax.h"
#include "rtc_base/time_utils.h"
namespace webrtc {
namespace {
std::unique_ptr<RtcEventLogEncoder> CreateEncoder(const Environment& env) {
if (env.field_trials().IsDisabled("WebRTC-RtcEventLogNewFormat")) {
RTC_DLOG(LS_INFO) << "Creating legacy encoder for RTC event log.";
return std::make_unique<RtcEventLogEncoderLegacy>();
} else {
RTC_DLOG(LS_INFO) << "Creating new format encoder for RTC event log.";
return std::make_unique<RtcEventLogEncoderNewFormat>(env.field_trials());
}
}
} // namespace
RtcEventLogImpl::RtcEventLogImpl(const Environment& env)
: RtcEventLogImpl(CreateEncoder(env), &env.task_queue_factory()) {}
RtcEventLogImpl::RtcEventLogImpl(std::unique_ptr<RtcEventLogEncoder> encoder,
TaskQueueFactory* task_queue_factory,
size_t max_events_in_history,
size_t max_config_events_in_history)
: max_events_in_history_(max_events_in_history),
max_config_events_in_history_(max_config_events_in_history),
event_encoder_(std::move(encoder)),
last_output_ms_(rtc::TimeMillis()),
task_queue_(task_queue_factory->CreateTaskQueue(
"rtc_event_log",
TaskQueueFactory::Priority::NORMAL)) {}
RtcEventLogImpl::~RtcEventLogImpl() {
// If we're logging to the output, this will stop that. Blocking function.
mutex_.Lock();
bool started = logging_state_started_;
mutex_.Unlock();
if (started) {
logging_state_checker_.Detach();
StopLogging();
}
// Since we are posting tasks bound to `this`, it is critical that the event
// log and its members outlive `task_queue_`. Destruct `task_queue_` first
// to ensure tasks living on the queue can access other members.
// We want to block on any executing task by deleting TaskQueue before
// we set unique_ptr's internal pointer to null.
task_queue_.get_deleter()(task_queue_.get());
task_queue_.release();
}
bool RtcEventLogImpl::StartLogging(std::unique_ptr<RtcEventLogOutput> output,
int64_t output_period_ms) {
RTC_DCHECK(output);
RTC_DCHECK(output_period_ms == kImmediateOutput || output_period_ms > 0);
if (!output->IsActive()) {
// TODO(eladalon): We may want to remove the IsActive method. Otherwise
// we probably want to be consistent and terminate any existing output.
return false;
}
const int64_t timestamp_us = rtc::TimeMillis() * 1000;
const int64_t utc_time_us = rtc::TimeUTCMillis() * 1000;
RTC_LOG(LS_INFO) << "Starting WebRTC event log. (Timestamp, UTC) = ("
<< timestamp_us << ", " << utc_time_us << ").";
RTC_DCHECK_RUN_ON(&logging_state_checker_);
MutexLock lock(&mutex_);
logging_state_started_ = true;
immediately_output_mode_ = (output_period_ms == kImmediateOutput);
need_schedule_output_ = (output_period_ms != kImmediateOutput);
// Binding to `this` is safe because `this` outlives the `task_queue_`.
task_queue_->PostTask([this, output_period_ms, timestamp_us, utc_time_us,
output = std::move(output),
histories = ExtractRecentHistories()]() mutable {
RTC_DCHECK_RUN_ON(task_queue_.get());
RTC_DCHECK(output);
RTC_DCHECK(output->IsActive());
output_period_ms_ = output_period_ms;
event_output_ = std::move(output);
WriteToOutput(event_encoder_->EncodeLogStart(timestamp_us, utc_time_us));
// Load all configs of previous sessions.
if (!all_config_history_.empty()) {
EventDeque& history = histories.config_history;
history.insert(history.begin(),
std::make_move_iterator(all_config_history_.begin()),
std::make_move_iterator(all_config_history_.end()));
all_config_history_.clear();
if (history.size() > max_config_events_in_history_) {
RTC_LOG(LS_WARNING)
<< "Dropping config events: " << history.size()
<< " exceeds maximum " << max_config_events_in_history_;
history.erase(history.begin(), history.begin() + history.size() -
max_config_events_in_history_);
}
}
LogEventsToOutput(std::move(histories));
});
return true;
}
void RtcEventLogImpl::StopLogging() {
RTC_DLOG(LS_INFO) << "Stopping WebRTC event log.";
// TODO(bugs.webrtc.org/14449): Do not block current thread waiting on the
// task queue. It might work for now, for current callers, but disallows
// caller to share threads with the `task_queue_`.
rtc::Event output_stopped;
StopLogging([&output_stopped]() { output_stopped.Set(); });
output_stopped.Wait(rtc::Event::kForever);
RTC_DLOG(LS_INFO) << "WebRTC event log successfully stopped.";
}
void RtcEventLogImpl::StopLogging(std::function<void()> callback) {
RTC_DCHECK_RUN_ON(&logging_state_checker_);
MutexLock lock(&mutex_);
logging_state_started_ = false;
task_queue_->PostTask(
[this, callback, histories = ExtractRecentHistories()]() mutable {
RTC_DCHECK_RUN_ON(task_queue_.get());
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
LogEventsToOutput(std::move(histories));
}
StopLoggingInternal();
callback();
});
}
RtcEventLogImpl::EventHistories RtcEventLogImpl::ExtractRecentHistories() {
EventHistories histories;
std::swap(histories, recent_);
return histories;
}
void RtcEventLogImpl::Log(std::unique_ptr<RtcEvent> event) {
RTC_CHECK(event);
MutexLock lock(&mutex_);
LogToMemory(std::move(event));
if (logging_state_started_) {
if (ShouldOutputImmediately()) {
// Binding to `this` is safe because `this` outlives the `task_queue_`.
task_queue_->PostTask(
[this, histories = ExtractRecentHistories()]() mutable {
RTC_DCHECK_RUN_ON(task_queue_.get());
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
LogEventsToOutput(std::move(histories));
}
});
} else if (need_schedule_output_) {
need_schedule_output_ = false;
// Binding to `this` is safe because `this` outlives the `task_queue_`.
task_queue_->PostTask([this]() mutable {
RTC_DCHECK_RUN_ON(task_queue_.get());
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
ScheduleOutput();
}
});
}
}
}
bool RtcEventLogImpl::ShouldOutputImmediately() {
if (recent_.history.size() >= max_events_in_history_) {
// We have to emergency drain the buffer. We can't wait for the scheduled
// output task because there might be other event incoming before that.
return true;
}
return immediately_output_mode_;
}
void RtcEventLogImpl::ScheduleOutput() {
RTC_DCHECK(output_period_ms_ != kImmediateOutput);
// Binding to `this` is safe because `this` outlives the `task_queue_`.
auto output_task = [this]() {
RTC_DCHECK_RUN_ON(task_queue_.get());
// Allow scheduled output if the `event_output_` is valid.
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
mutex_.Lock();
RTC_DCHECK(!need_schedule_output_);
// Let the next `Log()` to schedule output.
need_schedule_output_ = true;
EventHistories histories = ExtractRecentHistories();
mutex_.Unlock();
LogEventsToOutput(std::move(histories));
}
};
const int64_t now_ms = rtc::TimeMillis();
const int64_t time_since_output_ms = now_ms - last_output_ms_;
const int32_t delay = rtc::SafeClamp(output_period_ms_ - time_since_output_ms,
0, output_period_ms_);
task_queue_->PostDelayedTask(std::move(output_task),
TimeDelta::Millis(delay));
}
void RtcEventLogImpl::LogToMemory(std::unique_ptr<RtcEvent> event) {
EventDeque& container =
event->IsConfigEvent() ? recent_.config_history : recent_.history;
const size_t container_max_size = event->IsConfigEvent()
? max_config_events_in_history_
: max_events_in_history_;
// Shouldn't lose events if started.
if (container.size() >= container_max_size && !logging_state_started_) {
container.pop_front();
}
container.push_back(std::move(event));
}
void RtcEventLogImpl::LogEventsToOutput(EventHistories histories) {
last_output_ms_ = rtc::TimeMillis();
// Serialize the stream configurations.
std::string encoded_configs = event_encoder_->EncodeBatch(
histories.config_history.begin(), histories.config_history.end());
// Serialize the events in the event queue. Note that the write may fail,
// for example if we are writing to a file and have reached the maximum limit.
// We don't get any feedback if this happens, so we still remove the events
// from the event log history. This is normally not a problem, but if another
// log is started immediately after the first one becomes full, then one
// cannot rely on the second log to contain everything that isn't in the first
// log; one batch of events might be missing.
std::string encoded_history = event_encoder_->EncodeBatch(
histories.history.begin(), histories.history.end());
WriteConfigsAndHistoryToOutput(encoded_configs, encoded_history);
// Unlike other events, the configs are retained. If we stop/start logging
// again, these configs are used to interpret other events.
all_config_history_.insert(
all_config_history_.end(),
std::make_move_iterator(histories.config_history.begin()),
std::make_move_iterator(histories.config_history.end()));
if (all_config_history_.size() > max_config_events_in_history_) {
RTC_LOG(LS_WARNING) << "Dropping config events: "
<< all_config_history_.size() << " exceeds maximum "
<< max_config_events_in_history_;
all_config_history_.erase(all_config_history_.begin(),
all_config_history_.begin() +
all_config_history_.size() -
max_config_events_in_history_);
}
}
void RtcEventLogImpl::WriteConfigsAndHistoryToOutput(
absl::string_view encoded_configs,
absl::string_view encoded_history) {
// This function is used to merge the strings instead of calling the output
// object twice with small strings. The function also avoids copying any
// strings in the typical case where there are no config events.
if (encoded_configs.empty()) {
WriteToOutput(encoded_history); // Typical case.
} else if (encoded_history.empty()) {
WriteToOutput(encoded_configs); // Very unusual case.
} else {
std::string s;
s.reserve(encoded_configs.size() + encoded_history.size());
s.append(encoded_configs.data(), encoded_configs.size());
s.append(encoded_history.data(), encoded_history.size());
WriteToOutput(s);
}
}
void RtcEventLogImpl::StopOutput() {
event_output_.reset();
}
void RtcEventLogImpl::StopLoggingInternal() {
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
const int64_t timestamp_us = rtc::TimeMillis() * 1000;
event_output_->Write(event_encoder_->EncodeLogEnd(timestamp_us));
}
StopOutput();
}
void RtcEventLogImpl::WriteToOutput(absl::string_view output_string) {
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
if (!event_output_->Write(output_string)) {
RTC_LOG(LS_ERROR) << "Failed to write RTC event to output.";
// The first failure closes the output.
RTC_DCHECK(!event_output_->IsActive());
StopOutput(); // Clean-up.
}
}
}
} // namespace webrtc
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