Use environmental variables in filebeat configuration?

Hi,

I would like to add some fields to some log inputs.
Lets say I have an environmental variable path1=my_first_instance

Is it possible to configure something like this in the input configuration?

fields:
  instance: ${path1}

If so, will it be updated on the fly? Meaning, if I change the environmental variable, will the field value change immediately without restarting filebeat?

You can use environment variables in your configuration. See more: https://www.elastic.co/guide/en/beats/filebeat/current/using-environ-vars.html

If the value of the environment variable is changed, Filebeat needs to be restarted.

thanks