Add OTLP logging and link logs with traces

[gr1ckly]

Hi! Your project uses OTLP tracing. Would you like to add OTLP logging and link traces and logs using OTLP as well? I realize this is still experimental, but it can be implemented by moving logging into a separate module and hiding the implementation behind a public interface. Trace and attribute information can be passed to the logging methods via the context.

[EdSchouten]

In a world where we already have tracing and metrics, there isn't really a need to do logging. This is also one of the reasons Buildbarn hardly logs anything. I therefore don't think there's any value in using OTLP logging, unless there's something I'm overlooking.

[gr1ckly]

Thank you for your reply!
In my mind, structured logs allow us to pass more context and data about what’s happening in a given place in our code. Additionally, log levels enable us to configure the level of detail we receive about our application’s behavior when it’s running (we may toggle debug level on a particular service we are trying to debug for example). It also raises questions about how to store, index and query trace metadata, - having a separate backend dedicated to storing/processing/indexing/rotating structured logs may come handy.
Moreover, structured logs are relatively easy to add to a project, especially when you already have OTLP set up for tracing, which automatically assigns trace id/span id to logs, and then we could use tools like Grafana to seamlessly switch between traces and logs.