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// Copyright 2016 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/main/cpp/util/bazel_log_handler.h"
#include <chrono> // NOLINT -- for windows portability
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <sstream>
#include "src/main/cpp/util/exit_code.h"
#include "src/main/cpp/util/file.h"
#include "src/main/cpp/util/logging.h"
namespace blaze_util {
BazelLogHandler::BazelLogHandler()
: output_stream_set_(false),
logging_deactivated_(false),
user_buffer_stream_(new std::stringstream()),
debug_buffer_stream_(new std::stringstream()),
output_stream_(),
owned_output_stream_() {}
BazelLogHandler::~BazelLogHandler() {
if (!logging_deactivated_) {
// If SetLoggingOutputStream was never called, dump the buffer to stderr,
// otherwise, flush the stream.
if (output_stream_ != nullptr) {
output_stream_->flush();
} else if (debug_buffer_stream_ != nullptr) {
std::cerr << debug_buffer_stream_->rdbuf();
} else {
std::cerr << "Illegal state - neither a logfile nor a logbuffer "
<< "existed at program end." << std::endl;
}
}
}
// Messages intended for the user (level USER, along with WARNINGs an ERRORs)
// should be printed even if debug level logging was not requested.
void PrintUserLevelMessageToStream(std::ostream* stream, LogLevel level,
const std::string& message) {
if (level == LOGLEVEL_USER) {
(*stream) << message << std::endl;
} else if (level > LOGLEVEL_USER) {
(*stream) << LogLevelName(level) << ": " << message << std::endl;
}
// If level < USER, this is an INFO message. It's useful for debugging but
// should not be printed to the user unless the user has asked for debugging
// output. We ignore it here.
}
static std::string Timestamp() {
auto now = std::chrono::system_clock::now();
time_t s = std::chrono::system_clock::to_time_t(now);
auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(
now.time_since_epoch());
struct tm tmbuf = {};
#ifdef _WIN32
tmbuf = *localtime(&s); // NOLINT -- threadsafe on windows
#else
localtime_r(&s, &tmbuf);
#endif
char buf[16];
int r = strftime(buf, sizeof buf - 5, "%H:%M:%S", &tmbuf);
r += snprintf(buf + r, +5, ".%03d", static_cast<int>(ms.count() % 1000));
return std::string(buf, r);
}
// For debug logs, print all logs, both debug logging and USER logs and above,
// along with information about where the log message came from.
void PrintDebugLevelMessageToStream(std::ostream* stream,
const std::string& filename, int line,
LogLevel level,
const std::string& message) {
(*stream) << "[" << LogLevelName(level) << " " << Timestamp() << " "
<< filename << ":" << line << "] " << message << std::endl;
}
void BazelLogHandler::HandleMessage(LogLevel level, const std::string& filename,
int line, const std::string& message,
int exit_code) {
if (logging_deactivated_) {
// If the output stream was explicitly deactivated, never print INFO
// messages, but messages of level USER and above should always be printed,
// as should warnings and errors. Omit the debug-level file and line number
// information, though.
PrintUserLevelMessageToStream(&std::cerr, level, message);
if (level == LOGLEVEL_FATAL) {
std::exit(exit_code);
}
return;
}
if (output_stream_ == nullptr) {
// If we haven't decided whether messages should be logged to debug levels
// or not, buffer each version. This is redundant for USER levels and above,
// but is to make sure we can provide the right output to the user once we
// know that they do or do not want debug level information.
PrintUserLevelMessageToStream(user_buffer_stream_.get(), level, message);
PrintDebugLevelMessageToStream(debug_buffer_stream_.get(), filename, line,
level, message);
} else {
// If an output stream has been specifically set, it is for the full suite
// of log messages. We don't print the user messages separately here as they
// are included.
PrintDebugLevelMessageToStream(output_stream_, filename, line, level,
message);
}
// If we have a fatal message, exit with the provided error code.
if (level == LOGLEVEL_FATAL) {
if (owned_output_stream_ != nullptr) {
// If this is is not being printed to stderr but to a custom stream,
// also print the error message to stderr.
PrintUserLevelMessageToStream(&std::cerr, level, message);
}
std::exit(exit_code);
}
}
void BazelLogHandler::SetOutputStreamToStderr() {
// Disallow second calls to this, we only intend to support setting the output
// once, otherwise the buffering will not work as intended and the log will be
// fragmented.
BAZEL_CHECK(!output_stream_set_) << "Tried to set log output a second time";
output_stream_set_ = true;
FlushBufferToNewStreamAndSet(debug_buffer_stream_.get(), &std::cerr);
debug_buffer_stream_ = nullptr;
// The user asked for debug level information, which includes the user
// messages. We can discard the separate buffer at this point.
user_buffer_stream_ = nullptr;
}
void BazelLogHandler::SetOutputStream(
std::unique_ptr<std::ostream> new_output_stream) {
// Disallow second calls to this, we only intend to support setting the output
// once, otherwise the buffering will not work as intended and the log will be
// fragmented.
BAZEL_CHECK(!output_stream_set_) << "Tried to set log output a second time";
output_stream_set_ = true;
if (new_output_stream == nullptr) {
logging_deactivated_ = true;
// Flush the buffered user-level messages to stderr - these are messages
// that are meant for the user even when debug logging is not set.
FlushBufferToNewStreamAndSet(user_buffer_stream_.get(), &std::cerr);
user_buffer_stream_ = nullptr;
// We discard the debug level logs, the user level ones were enough to
// inform the user and debug logging was not requested.
debug_buffer_stream_ = nullptr;
return;
}
owned_output_stream_ = std::move(new_output_stream);
if (owned_output_stream_->fail()) {
// If opening the stream failed, continue buffering and have the logs
// dump to stderr at shutdown.
BAZEL_LOG(ERROR) << "Provided stream failed.";
return;
}
FlushBufferToNewStreamAndSet(debug_buffer_stream_.get(),
owned_output_stream_.get());
debug_buffer_stream_ = nullptr;
// The user asked for debug level information, which includes the user
// messages. We can discard the separate buffer at this point.
user_buffer_stream_ = nullptr;
}
void BazelLogHandler::FlushBufferToNewStreamAndSet(
std::stringstream* buffer, std::ostream* new_output_stream) {
// Flush the buffer to the new stream, and print new log lines to it.
output_stream_ = new_output_stream;
// Transfer the contents of the buffer to the new stream, then remove the
// buffer.
(*output_stream_) << buffer->str();
output_stream_->flush();
}
} // namespace blaze_util