fluent-plugin-file2

Re-implementation of out_file plugin for Fluentd.

Problems of out_file

1. out_file plugin is not thread-safe and process-safe. See http://d.hatena.ne.jp/sfujiwara/20121027/1351330488 (Japanese)
2. out_file plugin creates multiple separated buffer files on running multiple threads (and processes). Want to write into one file cuncurrently from multiple threads (and processes).
3. Because of 2, symlink_path option will be broken under multiple threads (or processes)
4. Complex (Do we really need the File Buffer before writing file? Both is file!)

Strategy

The fundamental strategy to solve above problems is:

Specify path with time format, and just append contents to the strftime filename from multiple threads (and processes). No buffer file is generated anymore. This is the same strategy with strftime_logger, which is already running on my production environment.

For compression, create a thread for compression running in an interval implied by the time format in the path (like 1 hour interval for %H) to compress a previously generated file. The thread and process safety is achieved by a delicate implementation, just for compatibility with out_file, although I actually think running another cron job for compression is better approach.

Example

See example.conf

Configuration

Basically same with out_file plugin. You may see the doc of out_file.

• path

  The path of the file such as foo.%Y%m%d%H.log.

  The time format used as part of the file name. The following characters are replaced with actual values when the file is created:

  • %Y: year including the century (at least 4 digits)
  • %m: month of the year (01..12)
  • %d: Day of the month (01..31)
  • %H: Hour of the day, 24-hour clock (00..23)
  • %M: Minute of the hour (00..59)
  • %S: Second of the minute (00..60)

• time_slice_format (obsolete)

  This option is provided just for compatibility with out_file. Use time format in path parameter instead.

• format

  The format of the file content. The default is out_file.

  Please refer out_file#format.

• time_format

  The format of the time written in files. The default format is ISO-8601.

• utc

  Uses UTC for path formatting. The default format is localtime.

• compress

  Compresses files using gzip. No compression is performed by default.

• time_slice_wait (obsolete)

  This option is provided just for compatibility with out_file. Use compress_wait instead.

• compress_wait

  The amount of time Fluentd will wait for old logs to compress. This is used to account for delays in logs arriving to your Fluentd node. The default wait time is 10 minutes (‘10m’), where Fluentd will wait until 10 minutes past the hour for any logs that occured within the past hour.

  For example, when splitting files on an hourly basis, a log recorded at 1:59 but arriving at the Fluentd node between 2:00 and 2:10 will be uploaded together with all the other logs from 1:00 to 1:59 in one transaction, avoiding extra overhead. Larger values can be set as needed.

• symlink_path

  Create symlink to the newest file created.. No symlink is created by default. This is useful for tailing file content to check logs.

Differences

Notable differences with out_file:

• No buffer file is generated.
• append true|false option was removed. Always append true.
• Filename is expanded using the current time, rather than the time in a chunk.

ChangeLog

See CHANGELOG.md for details.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Copyright

Copyright (c) 2014 Naotoshi Seo. See LICENSE for details.