| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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. |
| #ifndef KUDU_UTIL_ROLLING_LOG_H |
| #define KUDU_UTIL_ROLLING_LOG_H |
| |
| #include <cstdint> |
| #include <memory> |
| #include <string> |
| |
| #include "kudu/gutil/macros.h" |
| #include "kudu/gutil/port.h" |
| #include "kudu/gutil/strings/stringpiece.h" |
| #include "kudu/util/status.h" |
| |
| namespace kudu { |
| |
| class Env; |
| class WritableFile; |
| |
| // A simple rolling log. |
| // |
| // This creates a log which spans multiple files in a specified directory. |
| // After a log file reaches a specified size threshold, it automatically rolls |
| // to the next file in the sequence. |
| // |
| // The files are named similarly to glog log files and use the following pattern: |
| // |
| // <log_dir>/<program-name>.<hostname>.<user-name>.<log-name>.<timestamp>.<sequence>.<pid> |
| // log_dir: the log_dir specified in the constructor |
| // program-name: the name of the program specified in the constructor. If unset, defaults |
| // to argv[0], as determined by google::ProgramInvocationShortName(). |
| // hostname: the local machine hostname |
| // user-name: the current user name |
| // log-name: the log_name specified in the constructor |
| // timestamp: the wall clock time when the log file was created, in |
| // YYYYmmdd-HHMMSS fixed-length format. |
| // sequence: a sequence number which is used to disambiguate when the log file is |
| // rolled multiple times within a second |
| // pid: the pid of the daemon |
| // |
| // The log implementation does not ensure durability of the log or its files in any way. |
| // This class is not thread-safe and must be externally synchronized. |
| class RollingLog { |
| public: |
| RollingLog(Env* env, std::string log_dir, std::string program_name, std::string log_name); |
| |
| ~RollingLog(); |
| |
| // Open the log. |
| // It is optional to call this function. Append() will automatically open |
| // the log as necessary if it is not open. |
| Status Open(); |
| |
| // Set the pre-compression size threshold at which the log file will be rolled. |
| // If the log is already open, this applies for the the current and any future |
| // log file. |
| // |
| // NOTE: This is the limit on a single segment of the log, not a limit on the total |
| // size of the log. |
| // |
| // NOTE: The threshold is checked _after_ each call to Append(). So, the size of |
| // the log may overshoot this threshold by as much as the size of a single appended |
| // message. |
| void SetRollThresholdBytes(int64_t size); |
| |
| // Set the total number of log segments to be retained. When the log is rolled, |
| // old segments are removed to achieve the targeted number of segments. |
| void SetMaxNumSegments(int num_segments); |
| |
| // If compression is enabled, log files are compressed. |
| // NOTE: this requires that the passed-in Env instance is the local file system. |
| void SetCompressionEnabled(bool compress); |
| |
| // Append the given data to the current log file. |
| // |
| // If, after appending this data, the file size has crossed the configured roll |
| // threshold, a new empty log file is created. Note that this is a synchronous API and |
| // causes potentially-blocking IO on the current thread. However, this does not fsync() |
| // or otherwise ensure durability of the appended data. |
| Status Append(StringPiece data) WARN_UNUSED_RESULT; |
| |
| // Close the log. |
| Status Close(); |
| |
| // Return the number of times this log has rolled since it was first opened. |
| int roll_count() const { |
| return roll_count_; |
| } |
| |
| private: |
| std::string GetLogFileName(int sequence) const; |
| |
| // Get a glob pattern matching all log files written by this instance. |
| std::string GetLogFilePattern() const; |
| |
| // Compress the given path, writing a new file '<path>.gz'. |
| Status CompressFile(const std::string& path) const; |
| |
| Env* const env_; |
| const std::string log_dir_; |
| const std::string program_name_; |
| const std::string log_name_; |
| |
| int64_t roll_threshold_bytes_; |
| int max_num_segments_; |
| |
| std::unique_ptr<WritableFile> file_; |
| bool compress_after_close_; |
| |
| int roll_count_ = 0; |
| |
| DISALLOW_COPY_AND_ASSIGN(RollingLog); |
| }; |
| |
| } // namespace kudu |
| #endif /* KUDU_UTIL_ROLLING_LOG_H */ |