Calyptia Core Agent supports the usage of environment variables in any value associated to a key when using a configuration file.

The variables are case sensitive and can be used in the following format:


When Calyptia Core Agent starts, the configuration reader will detect any request for ${MY_VARIABLE} and will try to resolve its value.

When Calyptia Core Agent is running under systemd (using the official packages), environment variables can be set in the following files:

  • /etc/default/calyptia-fluent-bit (Debian based system)

  • /etc/sysconfig/calyptia-fluent-bit (Others)

These files are ignored if they do not exist.


Create the following configuration file (calyptia-fluent-bit.conf):

    Flush        1
    Daemon       Off
    Log_Level    info

    Name cpu
    Tag  cpu.local

    Name  ${MY_OUTPUT}
    Match *

Open a terminal and set the environment variable:

export MY_OUTPUT=stdout

The above command set the 'stdout' value to the variable MY_OUTPUT.

Run Calyptia Core Agent with the recently created configuration file:

$ bin/calyptia-fluent-bit -c calyptia-fluent-bit.conf
Calyptia Fluent Bit 20.10.03

[2020/03/03 12:25:25] [ info] [engine] started
[0] cpu.local: [1491243925, {"cpu_p"=>1.750000, "user_p"=>1.750000, "system_p"=>0.000000, "cpu0.p_cpu"=>3.000000, "cpu0.p_user"=>2.000000, "cpu0.p_system"=>1.000000, "cpu1.p_cpu"=>0.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>0.000000, "cpu2.p_cpu"=>4.000000, "cpu2.p_user"=>4.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>1.000000, "cpu3.p_user"=>1.000000, "cpu3.p_system"=>0.000000}]

As you can see the service worked properly as the configuration was valid.

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