Formatter Plugins

Fluentd has nine (9) types of plugins:
​Input​
​Parser​
​Filter​
​Output​
​Formatter​
​Storage​
​Service Discovery​
​Buffer​
​Metrics​
This article gives an overview of the Formatter Plugin.
Overview
Sometimes, the output format for an output plugin does not meet one's needs. Fluentd has a pluggable system called Formatter that lets the user extend and re-use custom output formats.
How To Use
For an output plugin that supports Formatter, the <format> directive can be used to change the output format.
For example, by default, out_file plugin outputs data as
2014-08-25 00:00:00 +0000<TAB>foo.bar<TAB>{"k1":"v1", "k2":"v2"}
However, if you set @type json in <format> like this:
<match foo.bar>
  @type file
  path /path/to/file
  <format>
    @type json
  </format>
</match>
The output changes to
{"k1":"v1", "k2":"v2"}
i.e., each line is a single JSON object without "time" and "tag" fields. If you want to include "time" and "tag", use Inject section.
See this section to learn how to develop a custom formatter.
List of Built-in Formatters
​out_file​
​json​
​ltsv​
​csv​
​msgpack​
​hash​
​single_value​
​tsv​
List of Output/Filter Plugins with Formatter Support
​filter_stdout​
​out_file​
​out_s3​
If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.

none

out_file

Last modified 11mo ago