exporter/loki: handle multi-tenant use-cases

[jpkrohling]

This PR deprecates the existing tenant_id field in favor of a new tenant object, with a "source" and "value". The tenant information now may come from a resource attribute, from the context, or as a static value. Current setups using tenant_id are converted internally to "static".

This has been tested with a configuration similar to this:

receivers:
  journald:
    directory: /var/log/journal/a04e3a44cdd740f88d6a7ae3bb8c70cf

exporters:
  logging:
    loglevel: debug
  loki:
    endpoint: http://localhost:3100/loki/api/v1/push
    tls:
      insecure: true
    labels:
      attributes:
        host.name: host_name 
    format: json
    tenant:
      source: attributes
      value: tenant

processors:
  attributes:
    actions:
    - action: insert
      key: host.name
      value: guarana
  resource:
    attributes:
    - action: insert
      key: tenant
      value: acme

extensions:

service:
  extensions:
  pipelines:
    logs:
      receivers: [journald]
      processors: [attributes, resource]
      exporters: [logging, loki]

Configuring a different tenant and a different data source on Grafana confirmed that only logs with the new tenant attribute show up there, now showing up on the first data source.

Fixes #3121

Signed-off-by: Juraci Paixão Kröhling juraci@kroehling.de

[jpkrohling]

@dashpole, are you available to review this one?

[TylerHelmuth]

What happens if both Tenant and TenantID are used at the same time?

[jpkrohling]

Tenant takes precedence, but now that you mention it, I think it should actually at least generate a warning or fail during the Validate step.

[TylerHelmuth]

I like failing. Maybe a little harsh, but mixing deprecated fields and their replacement fields feels like something we should help our users avoid.

[jpkrohling]

PR updated

[TylerHelmuth]

Suggested change

	component: exporter/loki
	component: lokiexporter

[jpkrohling]

There actually was a discussion in the past on which format folks preferred, and having the component type followed by the component's name (without the type) was chosen:

#6688

[TylerHelmuth]

oh, we should start enforcing that then, the changelog is almost exclusively the other method haha