Formatting structured Loki log attributes into message body template

Grafana
1

I’m using Grafana+Loki+OTLP.

I’m injecting data from a .NET application that produces structured logs. The resulting logs have their message format separate from the provided arguments.

E.g.:

{  
  "body": "The localization namespace '{Namespace}' was not found",
  "severity": "Error",
  "attributes": {
    "Namespace": "Common"
  },
  "resources": {
    "service.instance.id": "115812fc-9130-430e-af6d-4d7566a2750e",
    "service.name": "BOM.Client",
    "telemetry.sdk.language": "dotnet",
    "telemetry.sdk.name": "opentelemetry",
    "telemetry.sdk.version": "1.8.1"
  },
  "instrumentation\_scope": {
    "name": "Domain.Localization.Translator"
  }
}

As you can see, the message body is The localization namespace '{Namespace}' was not found. In a separate attributes field, you can see a key-value structure with the argument name and its value that is supposed to be placed into the body.

I’d want to format the message so that is like so: The localization namespace 'Common' was not found.

Using LogQL {exporter="OTLP"} | json body="body", severity="severity", attributes="attributes", scope="instrumentation\_scope\[\\"name\\"\]" | label\_format service=job

and the Extract fields data transformation (plus some color mappings and so on), I was able to create a decent dashboard table:

image
image940×314 117 KB

Could I format the body to contain the attributes? I’m unsure what the correct terminology is for this in Grafana.

I appreciate any help you can provide.