Add support for configuration by environment variables

[nmehlei]

Status

TASK

Checklist

• Add configuration via environment variables

Expected behaviour

The dotnet agent for New Relic can already be configured via environment variables, e.g. NEW_RELIC_LICENSE_KEY and NEW_RELIC_APP_NAME, which can be helpful in some hosting environments like Kubernetes. It would be great if this library could also use these values IF they are not already configured explicitly in e.g. the appsettings.json file. In my specific case, I would have to configure it both in environment variables as well as inside the appsettings.json. Especially the latter is both error-prone but also quite complicated when using Docker (and thus this sensible data is inside the docker container itself).

[ThiagoBarradas]

Please, can you test version 1.2.0-preview.1??

Let me know if all works fine to release final version as 1.2.0.

Thanks!!!

[nmehlei]

Thank you for the quick response! I'm currently testing it out, looks promising. Will get back to you afterwards.

[nmehlei]

Unfortunately, when configuring it this way, logs don't seem to reach New Relic. Just to confirm, this is supposed to be compatible with the configuration via JSON as well (i.e. without using the explicit .WriteTo.NewRelicLogs()), correct?