Use variables in monolog.services.yml file

Problem/Motivation

Hi,
I want to use this module to send formatted logs to syslog, but the host/ip change from one environment to another. I didn't find a way to add variables in Drupal services.yml (Symfony seems to provide it).

How can I achieve this ?

• Load environment specific monolog.services.yml ? :(
• Override it with settings.php and $settings['bootstrap_container_definition']?
• Use a specific services syntax (and install an additional Symfony package or Drupal module to do it)

Remaining tasks

I think a lot of log backends needs to use variables (filebeats, elastic, mongo, ...), so the correct "drupal" way to do this should be documented in the readme.