[exporter/loki] Make optional default labels exporter, job, instance, level

[mar4uk]

Component(s)

exporter/loki

Is your feature request related to a problem? Please describe.

Currently, loki exporter sets default labels:

• exporter=OTLP
• job=service.namespace/service.name
• instance=service.instance.id
• level=severity

For the user's convenience, it would be nice to make these labels optional

Related issues/discussions:

• [exporter/loki] Clarification about the hardcoded loki label "exporter=OTLP" #22155
• Loki exporter: how to remove default labels (job, level, exporter) #21508

Describe the solution you'd like

1. I would reconsider setting level label by default (it is actually not a good practice to promote log level to the label in Loki)
2. I would add default_labels section to the loki exporter config:

loki:
      endpoint: ...
      default_labels:
           job: false
           instance: false
           exporter: false

Describe alternatives you've considered

No response

Additional context

No response

[mar4uk]

/label exporter/loki

[gillg]

Thanks for taking care of this !

In my opinion, the hardcoded value OTLP should be renamed OpenTelemetry Collector or OtelCollector to make more sense.

[jpkrohling]

the hardcoded value OTLP should be renamed

Perhaps there should be an option to name it differently, but not a total rename right now. We'd need to give users notice in advance about this change.