New TLS certificates (e.g. renewal) do not automatically get loaded (even on SIGHUP)

[shric]

We automatically renew TLS certificates periodically and need to restart script_exporter to pick up the new certs. Other exporters such as node-exporter and snmp-exporter automatically pick up the latest cert file due to using the exporter-toolkit.

I noticed in https://github.com/ricoberger/script_exporter/issues/44 you commented in 2021 that you didn't want to introduce an additional configuration file for TLS, and therefore didn't want to use the exporter toolkit. However, I've noticed that since then you've supported separate config files for different scripts etc. so perhaps you're less reluctant to split today?

I believe using the exporter-toolkit would solve both https://github.com/ricoberger/script_exporter/issues/44 and this issue.

A large number of Go-based Prometheus things (e.g. prometheus and alertmanager themselves, node-exporter, snmp-exporter, etc.) use it, so users can point to a single web-config.yml.

If you have an interest in moving to use the toolkit but don't have the time or inclination to do so, I may attempt to send you a PR if you're open to the change, keen to know your thoughts.