blob: 735c9b34a66d20f84d5f62f4ad6581e9bd7b8da4 [file] [log] [blame]
/*
* 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.h"
#include <atomic>
#include <deque>
#include <functional>
#include <limits>
#include <memory>
#include <utility>
#include <vector>
#include "logging/rtc_event_log/encoder/rtc_event_log_encoder_legacy.h"
#include "logging/rtc_event_log/output/rtc_event_log_output_file.h"
#include "rtc_base/checks.h"
#include "rtc_base/constructormagic.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/ptr_util.h"
#include "rtc_base/sequenced_task_checker.h"
#include "rtc_base/task_queue.h"
#include "rtc_base/thread_annotations.h"
namespace webrtc {
#ifdef ENABLE_RTC_EVENT_LOG
namespace {
constexpr size_t kMaxEventsInHistory = 10000;
// The config-history is supposed to be unbounded, but needs to have some bound
// to prevent an attack via unreasonable memory use.
constexpr size_t kMaxEventsInConfigHistory = 1000;
// Observe a limit on the number of concurrent logs, so as not to run into
// OS-imposed limits on open files and/or threads/task-queues.
// TODO(eladalon): Known issue - there's a race over |rtc_event_log_count|.
std::atomic<int> rtc_event_log_count(0);
// TODO(eladalon): This class exists because C++11 doesn't allow transferring a
// unique_ptr to a lambda (a copy constructor is required). We should get
// rid of this when we move to C++14.
template <typename T>
class ResourceOwningTask final : public rtc::QueuedTask {
public:
ResourceOwningTask(std::unique_ptr<T> resource,
std::function<void(std::unique_ptr<T>)> handler)
: resource_(std::move(resource)), handler_(handler) {}
bool Run() override {
handler_(std::move(resource_));
return true;
}
private:
std::unique_ptr<T> resource_;
std::function<void(std::unique_ptr<T>)> handler_;
};
std::unique_ptr<RtcEventLogEncoder> CreateEncoder(
RtcEventLog::EncodingType type) {
switch (type) {
case RtcEventLog::EncodingType::Legacy:
return rtc::MakeUnique<RtcEventLogEncoderLegacy>();
default:
RTC_LOG(LS_ERROR) << "Unknown RtcEventLog encoder type (" << int(type)
<< ")";
RTC_NOTREACHED();
return std::unique_ptr<RtcEventLogEncoder>(nullptr);
}
}
class RtcEventLogImpl final : public RtcEventLog {
public:
explicit RtcEventLogImpl(std::unique_ptr<RtcEventLogEncoder> event_encoder);
~RtcEventLogImpl() override;
// TODO(eladalon): We should change these name to reflect that what we're
// actually starting/stopping is the output of the log, not the log itself.
bool StartLogging(std::unique_ptr<RtcEventLogOutput> output,
int64_t output_period_ms) override;
void StopLogging() override;
void Log(std::unique_ptr<RtcEvent> event) override;
private:
void LogToMemory(std::unique_ptr<RtcEvent> event) RTC_RUN_ON(&task_queue_);
void LogEventsFromMemoryToOutput() RTC_RUN_ON(&task_queue_);
void StopOutput() RTC_RUN_ON(&task_queue_);
void WriteConfigsAndHistoryToOutput(const std::string& encoded_configs,
const std::string& encoded_history)
RTC_RUN_ON(&task_queue_);
void WriteToOutput(const std::string& output_string) RTC_RUN_ON(&task_queue_);
void StopLoggingInternal() RTC_RUN_ON(&task_queue_);
void ScheduleOutput() RTC_RUN_ON(&task_queue_);
// Make sure that the event log is "managed" - created/destroyed, as well
// as started/stopped - from the same thread/task-queue.
rtc::SequencedTaskChecker owner_sequence_checker_;
// History containing all past configuration events.
std::deque<std::unique_ptr<RtcEvent>> config_history_
RTC_GUARDED_BY(task_queue_);
// History containing the most recent (non-configuration) events (~10s).
std::deque<std::unique_ptr<RtcEvent>> history_ RTC_GUARDED_BY(task_queue_);
size_t max_size_bytes_ RTC_GUARDED_BY(task_queue_);
size_t written_bytes_ RTC_GUARDED_BY(task_queue_);
std::unique_ptr<RtcEventLogEncoder> event_encoder_
RTC_GUARDED_BY(task_queue_);
std::unique_ptr<RtcEventLogOutput> event_output_ RTC_GUARDED_BY(task_queue_);
size_t num_config_events_written_ RTC_GUARDED_BY(task_queue_);
int64_t output_period_ms_ RTC_GUARDED_BY(task_queue_);
int64_t last_output_ms_ RTC_GUARDED_BY(task_queue_);
bool output_scheduled_ RTC_GUARDED_BY(task_queue_);
// Since we are posting tasks bound to |this|, it is critical that the event
// log and it's members outlive the |task_queue_|. Keep the "task_queue_|
// last to ensure it destructs first, or else tasks living on the queue might
// access other members after they've been torn down.
rtc::TaskQueue task_queue_;
RTC_DISALLOW_COPY_AND_ASSIGN(RtcEventLogImpl);
};
RtcEventLogImpl::RtcEventLogImpl(
std::unique_ptr<RtcEventLogEncoder> event_encoder)
: max_size_bytes_(std::numeric_limits<decltype(max_size_bytes_)>::max()),
written_bytes_(0),
event_encoder_(std::move(event_encoder)),
num_config_events_written_(0),
output_period_ms_(kImmediateOutput),
last_output_ms_(rtc::TimeMillis()),
output_scheduled_(false),
task_queue_("rtc_event_log") {}
RtcEventLogImpl::~RtcEventLogImpl() {
RTC_DCHECK_CALLED_SEQUENTIALLY(&owner_sequence_checker_);
// If we're logging to the output, this will stop that. Blocking function.
StopLogging();
int count = std::atomic_fetch_sub(&rtc_event_log_count, 1) - 1;
RTC_DCHECK_GE(count, 0);
}
bool RtcEventLogImpl::StartLogging(std::unique_ptr<RtcEventLogOutput> output,
int64_t output_period_ms) {
RTC_DCHECK_CALLED_SEQUENTIALLY(&owner_sequence_checker_);
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;
}
RTC_LOG(LS_INFO) << "Starting WebRTC event log.";
const int64_t timestamp_us = rtc::TimeMicros();
// Binding to |this| is safe because |this| outlives the |task_queue_|.
auto start = [this, timestamp_us](std::unique_ptr<RtcEventLogOutput> output) {
RTC_DCHECK_RUN_ON(&task_queue_);
RTC_DCHECK(output->IsActive());
event_output_ = std::move(output);
num_config_events_written_ = 0;
WriteToOutput(event_encoder_->EncodeLogStart(timestamp_us));
LogEventsFromMemoryToOutput();
};
task_queue_.PostTask(rtc::MakeUnique<ResourceOwningTask<RtcEventLogOutput>>(
std::move(output), start));
return true;
}
void RtcEventLogImpl::StopLogging() {
RTC_DCHECK_CALLED_SEQUENTIALLY(&owner_sequence_checker_);
RTC_LOG(LS_INFO) << "Stopping WebRTC event log.";
rtc::Event output_stopped(true, false);
// Binding to |this| is safe because |this| outlives the |task_queue_|.
task_queue_.PostTask([this, &output_stopped]() {
RTC_DCHECK_RUN_ON(&task_queue_);
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
LogEventsFromMemoryToOutput();
}
StopLoggingInternal();
output_stopped.Set();
});
output_stopped.Wait(rtc::Event::kForever);
RTC_LOG(LS_INFO) << "WebRTC event log successfully stopped.";
}
void RtcEventLogImpl::Log(std::unique_ptr<RtcEvent> event) {
RTC_DCHECK(event);
// Binding to |this| is safe because |this| outlives the |task_queue_|.
auto event_handler = [this](std::unique_ptr<RtcEvent> unencoded_event) {
RTC_DCHECK_RUN_ON(&task_queue_);
LogToMemory(std::move(unencoded_event));
if (event_output_)
ScheduleOutput();
};
task_queue_.PostTask(rtc::MakeUnique<ResourceOwningTask<RtcEvent>>(
std::move(event), event_handler));
}
void RtcEventLogImpl::ScheduleOutput() {
RTC_DCHECK(event_output_ && event_output_->IsActive());
if (history_.size() >= kMaxEventsInHistory) {
// 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.
LogEventsFromMemoryToOutput();
return;
}
if (output_period_ms_ == kImmediateOutput) {
// We are already on the |task_queue_| so there is no reason to post a task
// if we want to output immediately.
LogEventsFromMemoryToOutput();
return;
}
if (!output_scheduled_) {
output_scheduled_ = true;
// Binding to |this| is safe because |this| outlives the |task_queue_|.
auto output_task = [this]() {
RTC_DCHECK_RUN_ON(&task_queue_);
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
LogEventsFromMemoryToOutput();
}
output_scheduled_ = false;
};
int64_t now_ms = rtc::TimeMillis();
int64_t time_since_output_ms = now_ms - last_output_ms_;
uint32_t delay = rtc::SafeClamp(output_period_ms_ - time_since_output_ms, 0,
output_period_ms_);
task_queue_.PostDelayedTask(output_task, delay);
}
}
void RtcEventLogImpl::LogToMemory(std::unique_ptr<RtcEvent> event) {
std::deque<std::unique_ptr<RtcEvent>>& container =
event->IsConfigEvent() ? config_history_ : history_;
const size_t container_max_size =
event->IsConfigEvent() ? kMaxEventsInConfigHistory : kMaxEventsInHistory;
if (container.size() >= container_max_size) {
RTC_DCHECK(!event_output_); // Shouldn't lose events if we have an output.
container.pop_front();
}
container.push_back(std::move(event));
}
void RtcEventLogImpl::LogEventsFromMemoryToOutput() {
RTC_DCHECK(event_output_ && event_output_->IsActive());
last_output_ms_ = rtc::TimeMillis();
// Serialize all stream configurations that haven't already been written to
// this output. |num_config_events_written_| is used to track which configs we
// have already written. (Note that the config may have been written to
// previous outputs; configs are not discarded.)
std::string encoded_configs;
RTC_DCHECK_LE(num_config_events_written_, config_history_.size());
if (num_config_events_written_ < config_history_.size()) {
const auto begin = config_history_.begin() + num_config_events_written_;
const auto end = config_history_.end();
encoded_configs = event_encoder_->EncodeBatch(begin, end);
num_config_events_written_ = config_history_.size();
}
// 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(history_.begin(), history_.end());
history_.clear();
WriteConfigsAndHistoryToOutput(encoded_configs, encoded_history);
}
void RtcEventLogImpl::WriteConfigsAndHistoryToOutput(
const std::string& encoded_configs,
const std::string& 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.size() == 0) {
WriteToOutput(encoded_history); // Typical case.
} else if (encoded_history.size() == 0) {
WriteToOutput(encoded_configs); // Very unusual case.
} else {
WriteToOutput(encoded_configs + encoded_history);
}
}
void RtcEventLogImpl::StopOutput() {
max_size_bytes_ = std::numeric_limits<decltype(max_size_bytes_)>::max();
written_bytes_ = 0;
event_output_.reset();
}
void RtcEventLogImpl::StopLoggingInternal() {
if (event_output_) {
RTC_DCHECK(event_output_->IsActive());
const int64_t timestamp_us = rtc::TimeMicros();
event_output_->Write(event_encoder_->EncodeLogEnd(timestamp_us));
}
StopOutput();
}
void RtcEventLogImpl::WriteToOutput(const std::string& output_string) {
RTC_DCHECK(event_output_ && 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.
return;
}
written_bytes_ += output_string.size();
}
} // namespace
#endif // ENABLE_RTC_EVENT_LOG
// RtcEventLog member functions.
std::unique_ptr<RtcEventLog> RtcEventLog::Create(EncodingType encoding_type) {
#ifdef ENABLE_RTC_EVENT_LOG
// TODO(eladalon): Known issue - there's a race over |rtc_event_log_count|.
constexpr int kMaxLogCount = 5;
int count = 1 + std::atomic_fetch_add(&rtc_event_log_count, 1);
if (count > kMaxLogCount) {
RTC_LOG(LS_WARNING) << "Denied creation of additional WebRTC event logs. "
<< count - 1 << " logs open already.";
std::atomic_fetch_sub(&rtc_event_log_count, 1);
return CreateNull();
}
auto encoder = CreateEncoder(encoding_type);
return rtc::MakeUnique<RtcEventLogImpl>(std::move(encoder));
#else
return CreateNull();
#endif // ENABLE_RTC_EVENT_LOG
}
std::unique_ptr<RtcEventLog> RtcEventLog::CreateNull() {
return std::unique_ptr<RtcEventLog>(new RtcEventLogNullImpl());
}
} // namespace webrtc