1 files changed, 372 insertions, 0 deletions
diff --git a/src/rocksdb/logging/auto_roll_logger.cc b/src/rocksdb/logging/auto_roll_logger.cc
new file mode 100644
index 000000000..fe0958479
--- /dev/null
+++ b/src/rocksdb/logging/auto_roll_logger.cc
@@ -0,0 +1,372 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#include "logging/auto_roll_logger.h"
+
+#include <algorithm>
+
+#include "file/filename.h"
+#include "logging/logging.h"
+#include "rocksdb/env.h"
+#include "rocksdb/file_system.h"
+#include "rocksdb/system_clock.h"
+#include "util/mutexlock.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+#ifndef ROCKSDB_LITE
+// -- AutoRollLogger
+
+AutoRollLogger::AutoRollLogger(const std::shared_ptr<FileSystem>& fs,
+                               const std::shared_ptr<SystemClock>& clock,
+                               const std::string& dbname,
+                               const std::string& db_log_dir,
+                               size_t log_max_size,
+                               size_t log_file_time_to_roll,
+                               size_t keep_log_file_num,
+                               const InfoLogLevel log_level)
+    : Logger(log_level),
+      dbname_(dbname),
+      db_log_dir_(db_log_dir),
+      fs_(fs),
+      clock_(clock),
+      status_(Status::OK()),
+      kMaxLogFileSize(log_max_size),
+      kLogFileTimeToRoll(log_file_time_to_roll),
+      kKeepLogFileNum(keep_log_file_num),
+      cached_now(static_cast<uint64_t>(clock_->NowMicros() * 1e-6)),
+      ctime_(cached_now),
+      cached_now_access_count(0),
+      call_NowMicros_every_N_records_(100),
+      mutex_() {
+  Status s = fs->GetAbsolutePath(dbname, io_options_, &db_absolute_path_,
+                                 &io_context_);
+  if (s.IsNotSupported()) {
+    db_absolute_path_ = dbname;
+  } else {
+    status_ = s;
+  }
+  log_fname_ = InfoLogFileName(dbname_, db_absolute_path_, db_log_dir_);
+  if (fs_->FileExists(log_fname_, io_options_, &io_context_).ok()) {
+    RollLogFile();
+  }
+  GetExistingFiles();
+  s = ResetLogger();
+  if (s.ok() && status_.ok()) {
+    status_ = TrimOldLogFiles();
+  }
+}
+
+Status AutoRollLogger::ResetLogger() {
+  TEST_SYNC_POINT("AutoRollLogger::ResetLogger:BeforeNewLogger");
+  status_ = fs_->NewLogger(log_fname_, io_options_, &logger_, &io_context_);
+  TEST_SYNC_POINT("AutoRollLogger::ResetLogger:AfterNewLogger");
+
+  if (!status_.ok()) {
+    return status_;
+  }
+  assert(logger_);
+  logger_->SetInfoLogLevel(Logger::GetInfoLogLevel());
+
+  if (logger_->GetLogFileSize() == Logger::kDoNotSupportGetLogFileSize) {
+    status_ = Status::NotSupported(
+        "The underlying logger doesn't support GetLogFileSize()");
+  }
+  if (status_.ok()) {
+    cached_now = static_cast<uint64_t>(clock_->NowMicros() * 1e-6);
+    ctime_ = cached_now;
+    cached_now_access_count = 0;
+  }
+
+  return status_;
+}
+
+void AutoRollLogger::RollLogFile() {
+  // This function is called when log is rotating. Two rotations
+  // can happen quickly (NowMicro returns same value). To not overwrite
+  // previous log file we increment by one micro second and try again.
+  uint64_t now = clock_->NowMicros();
+  std::string old_fname;
+  do {
+    old_fname =
+        OldInfoLogFileName(dbname_, now, db_absolute_path_, db_log_dir_);
+    now++;
+  } while (fs_->FileExists(old_fname, io_options_, &io_context_).ok());
+  // Wait for logger_ reference count to turn to 1 as it might be pinned by
+  // Flush. Pinned Logger can't be closed till Flush is completed on that
+  // Logger.
+  while (logger_.use_count() > 1) {
+  }
+  // Close the existing logger first to release the existing handle
+  // before renaming the file using the file system. If this call
+  // fails there is nothing much we can do and we will continue with the
+  // rename and hence ignoring the result status.
+  if (logger_) {
+    logger_->Close().PermitUncheckedError();
+  }
+  Status s = fs_->RenameFile(log_fname_, old_fname, io_options_, &io_context_);
+  if (!s.ok()) {
+    // What should we do on error?
+  }
+  old_log_files_.push(old_fname);
+}
+
+void AutoRollLogger::GetExistingFiles() {
+  {
+    // Empty the queue to avoid duplicated entries in the queue.
+    std::queue<std::string> empty;
+    std::swap(old_log_files_, empty);
+  }
+
+  std::string parent_dir;
+  std::vector<std::string> info_log_files;
+  Status s =
+      GetInfoLogFiles(fs_, db_log_dir_, dbname_, &parent_dir, &info_log_files);
+  if (status_.ok()) {
+    status_ = s;
+  }
+  // We need to sort the file before enqueing it so that when we
+  // delete file from the front, it is the oldest file.
+  std::sort(info_log_files.begin(), info_log_files.end());
+
+  for (const std::string& f : info_log_files) {
+    old_log_files_.push(parent_dir + "/" + f);
+  }
+}
+
+Status AutoRollLogger::TrimOldLogFiles() {
+  // Here we directly list info files and delete them through FileSystem.
+  // The deletion isn't going through DB, so there are shortcomes:
+  // 1. the deletion is not rate limited by SstFileManager
+  // 2. there is a chance that an I/O will be issued here
+  // Since it's going to be complicated to pass DB object down to
+  // here, we take a simple approach to keep the code easier to
+  // maintain.
+
+  // old_log_files_.empty() is helpful for the corner case that
+  // kKeepLogFileNum == 0. We can instead check kKeepLogFileNum != 0 but
+  // it's essentially the same thing, and checking empty before accessing
+  // the queue feels safer.
+  while (!old_log_files_.empty() && old_log_files_.size() >= kKeepLogFileNum) {
+    Status s =
+        fs_->DeleteFile(old_log_files_.front(), io_options_, &io_context_);
+    // Remove the file from the tracking anyway. It's possible that
+    // DB cleaned up the old log file, or people cleaned it up manually.
+    old_log_files_.pop();
+    // To make the file really go away, we should sync parent directory.
+    // Since there isn't any consistency issue involved here, skipping
+    // this part to avoid one I/O here.
+    if (!s.ok()) {
+      return s;
+    }
+  }
+  return Status::OK();
+}
+
+std::string AutoRollLogger::ValistToString(const char* format,
+                                           va_list args) const {
+  // Any log messages longer than 1024 will get truncated.
+  // The user is responsible for chopping longer messages into multi line log
+  static const int MAXBUFFERSIZE = 1024;
+  char buffer[MAXBUFFERSIZE];
+
+  int count = vsnprintf(buffer, MAXBUFFERSIZE, format, args);
+  (void)count;
+  assert(count >= 0);
+
+  return buffer;
+}
+
+void AutoRollLogger::LogInternal(const char* format, ...) {
+  mutex_.AssertHeld();
+
+  if (!logger_) {
+    return;
+  }
+
+  va_list args;
+  va_start(args, format);
+  logger_->Logv(format, args);
+  va_end(args);
+}
+
+void AutoRollLogger::Logv(const char* format, va_list ap) {
+  assert(GetStatus().ok());
+  if (!logger_) {
+    return;
+  }
+
+  std::shared_ptr<Logger> logger;
+  {
+    MutexLock l(&mutex_);
+    if ((kLogFileTimeToRoll > 0 && LogExpired()) ||
+        (kMaxLogFileSize > 0 && logger_->GetLogFileSize() >= kMaxLogFileSize)) {
+      RollLogFile();
+      Status s = ResetLogger();
+      Status s2 = TrimOldLogFiles();
+
+      if (!s.ok()) {
+        // can't really log the error if creating a new LOG file failed
+        return;
+      }
+
+      WriteHeaderInfo();
+
+      if (!s2.ok()) {
+        ROCKS_LOG_WARN(logger.get(), "Fail to trim old info log file: %s",
+                       s2.ToString().c_str());
+      }
+    }
+
+    // pin down the current logger_ instance before releasing the mutex.
+    logger = logger_;
+  }
+
+  // Another thread could have put a new Logger instance into logger_ by now.
+  // However, since logger is still hanging on to the previous instance
+  // (reference count is not zero), we don't have to worry about it being
+  // deleted while we are accessing it.
+  // Note that logv itself is not mutex protected to allow maximum concurrency,
+  // as thread safety should have been handled by the underlying logger.
+  logger->Logv(format, ap);
+}
+
+void AutoRollLogger::WriteHeaderInfo() {
+  mutex_.AssertHeld();
+  for (auto& header : headers_) {
+    LogInternal("%s", header.c_str());
+  }
+}
+
+void AutoRollLogger::LogHeader(const char* format, va_list args) {
+  if (!logger_) {
+    return;
+  }
+
+  // header message are to be retained in memory. Since we cannot make any
+  // assumptions about the data contained in va_list, we will retain them as
+  // strings
+  va_list tmp;
+  va_copy(tmp, args);
+  std::string data = ValistToString(format, tmp);
+  va_end(tmp);
+
+  MutexLock l(&mutex_);
+  headers_.push_back(data);
+
+  // Log the original message to the current log
+  logger_->Logv(format, args);
+}
+
+bool AutoRollLogger::LogExpired() {
+  if (cached_now_access_count >= call_NowMicros_every_N_records_) {
+    cached_now = static_cast<uint64_t>(clock_->NowMicros() * 1e-6);
+    cached_now_access_count = 0;
+  }
+
+  ++cached_now_access_count;
+  return cached_now >= ctime_ + kLogFileTimeToRoll;
+}
+#endif  // !ROCKSDB_LITE
+
+Status CreateLoggerFromOptions(const std::string& dbname,
+                               const DBOptions& options,
+                               std::shared_ptr<Logger>* logger) {
+  if (options.info_log) {
+    *logger = options.info_log;
+    return Status::OK();
+  }
+
+  Env* env = options.env;
+  std::string db_absolute_path;
+  Status s = env->GetAbsolutePath(dbname, &db_absolute_path);
+  TEST_SYNC_POINT_CALLBACK("rocksdb::CreateLoggerFromOptions:AfterGetPath", &s);
+  if (!s.ok()) {
+    return s;
+  }
+  std::string fname =
+      InfoLogFileName(dbname, db_absolute_path, options.db_log_dir);
+
+  const auto& clock = env->GetSystemClock();
+  // In case it does not exist.
+  s = env->CreateDirIfMissing(dbname);
+  if (!s.ok()) {
+    if (options.db_log_dir.empty()) {
+      return s;
+    } else {
+      // Ignore the error returned during creation of dbname because dbname and
+      // db_log_dir can be on different filesystems in which case dbname will
+      // not exist and error should be ignored. db_log_dir creation will handle
+      // the error in case there is any error in the creation of dbname on same
+      // filesystem.
+      s = Status::OK();
+    }
+  }
+  assert(s.ok());
+
+  if (!options.db_log_dir.empty()) {
+    s = env->CreateDirIfMissing(options.db_log_dir);
+    if (!s.ok()) {
+      return s;
+    }
+  }
+#ifndef ROCKSDB_LITE
+  // Currently we only support roll by time-to-roll and log size
+  if (options.log_file_time_to_roll > 0 || options.max_log_file_size > 0) {
+    AutoRollLogger* result = new AutoRollLogger(
+        env->GetFileSystem(), clock, dbname, options.db_log_dir,
+        options.max_log_file_size, options.log_file_time_to_roll,
+        options.keep_log_file_num, options.info_log_level);
+    s = result->GetStatus();
+    if (!s.ok()) {
+      delete result;
+    } else {
+      logger->reset(result);
+    }
+    return s;
+  }
+#endif  // !ROCKSDB_LITE
+  // Open a log file in the same directory as the db
+  s = env->FileExists(fname);
+  if (s.ok()) {
+    s = env->RenameFile(
+        fname, OldInfoLogFileName(dbname, clock->NowMicros(), db_absolute_path,
+                                  options.db_log_dir));
+
+    // The operation sequence of "FileExists -> Rename" is not atomic. It's
+    // possible that FileExists returns OK but file gets deleted before Rename.
+    // This can cause Rename to return IOError with subcode PathNotFound.
+    // Although it may be a rare case and applications should be discouraged
+    // to not concurrently modifying the contents of the directories accessed
+    // by the database instance, it is still helpful if we can perform some
+    // simple handling of this case. Therefore, we do the following:
+    // 1. if Rename() returns IOError with PathNotFound subcode, then we check
+    //    whether the source file, i.e. LOG, exists.
+    // 2. if LOG exists, it means Rename() failed due to something else. Then
+    //    we report error.
+    // 3. if LOG does not exist, it means it may have been removed/renamed by
+    //    someone else. Since it does not exist, we can reset Status to OK so
+    //    that this caller can try creating a new LOG file. If this succeeds,
+    //    we should still allow it.
+    if (s.IsPathNotFound()) {
+      s = env->FileExists(fname);
+      if (s.IsNotFound()) {
+        s = Status::OK();
+      }
+    }
+  } else if (s.IsNotFound()) {
+    // "LOG" is not required to exist since this could be a new DB.
+    s = Status::OK();
+  }
+  if (s.ok()) {
+    s = env->NewLogger(fname, logger);
+  }
+  if (s.ok() && logger->get() != nullptr) {
+    (*logger)->SetInfoLogLevel(options.info_log_level);
+  }
+  return s;
+}
+
+}  // namespace ROCKSDB_NAMESPACE