The stdin plugin allows to retrieve valid JSON text messages over the standard input interface (stdin). In order to use it, specify the plugin name as the input, e.g:
$ fluent-bit -i stdin -o stdout
As input data the stdin plugin recognize the following JSON data formats:
1. { map => val, map => val, map => val }
2. [ time, { map => val, map => val, map => val } ]
A better example to demonstrate how it works will be through a Bash script that generates messages and writes them to Fluent Bit. Write the following content in a file named test.sh:
#!/bin/sh
while :; do
echo -n "{\"key\": \"some value\"}"
sleep 1
done
Give the script execution permission:
$ chmod 755 test.sh
Now lets start the script and Fluent Bit in the following way:
$ ./test.sh | fluent-bit -i stdin -o stdout
Fluent Bit v1.x.x
* Copyright (C) 2019-2020 The Fluent Bit Authors
* Copyright (C) 2015-2018 Treasure Data
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io
[2016/10/07 21:44:46] [ info] [engine] started
[0] stdin.0: [1475898286, {"key"=>"some value"}]
[1] stdin.0: [1475898287, {"key"=>"some value"}]
[2] stdin.0: [1475898288, {"key"=>"some value"}]
[3] stdin.0: [1475898289, {"key"=>"some value"}]
[4] stdin.0: [1475898290, {"key"=>"some value"}]