Overriding configuratin through environment variables/additional configuration files

[bojanmilevski]

Hello 👋

I would like to suggest two ideas that would benefit anyone who would like to keep track of their configuration in a git repository:

• Environment variables that will override AdGuardHome.yaml
• A folder (i.e. /etc/adguardhome/conf.d) where each configuration will override those in AdGuardHome.yaml

Currently, regarding IaC, all we can track is AdGuardHome.yaml, which can not be mounted as ro and causes problems with ownership, because it's owned by root.

I really like what Grafana is doing with environment variables. You can take a look here, but to summarize:

The following .env file:

export GF_DEFAULT_INSTANCE_NAME=my-instance
export GF_SECURITY_ADMIN_USER=owner
export GF_AUTH_GOOGLE_CLIENT_SECRET=newS3cretKey
export GF_PLUGIN_GRAFANA_IMAGE_RENDERER_RENDERING_IGNORE_HTTPS_ERRORS=true
export GF_FEATURE_TOGGLES_ENABLE=newNavigation

...results in the following grafana.ini file:

# default section
instance_name = ${HOSTNAME}

[security]
admin_user = admin

[auth.google]
client_secret = 0ldS3cretKey

[plugin.grafana-image-renderer]
rendering_ignore_https_errors = true

[feature_toggles]
enable = newNavigation

This is great! Each time Grafana is restarted, it parses the environment variables starting with GF_ and applies them to it's configuration file.

Regarding additional configuration files, I think it's pretty simple to understand: the main configuration file is read, then each additional file in a specific predefined directory, following alphabetical order - each overriding the previous one.

People have previously suggested this: #6647 and #7202.

I would be happy to implement both of my suggestions.

Cheers 👍