New component: Headers Setter extension for exporters

[kovrus]

The purpose and use-cases of the new component

The headers_setter extension implements configauth.GRPCClientAuthenticator
and is used to set requests headers in gRPC / HTTP exporters with values
provided via extension configurations or requests metadata (context).

Use cases include but are not limited to enabling multi-tenancy for observability
backends such as Tempo, Mimir, Loki and others by setting the X-Scope-OrgID
header to the value extracted from the context.

Once the extension implementation #12892 is accepted and merged, this extension can address the following issues:

• OTEL Exporter - multi-tenancy support based on labels opentelemetry-collector#5733

• [prometheusremotewriteexporter] multi-tenancy support based on labels #7945

• Auth-context available for use in export-config opentelemetry-collector#4814

• Provision to include request context(query params, headers) in AuthenticatorFunc opentelemetry-collector#4806

• Access headers in OTLP exporter opentelemetry-collector#5264

• We can drop specific multi-tenant implementation in loki/exporter exporter/loki: handle multi-tenant use-cases #12415

Example configuration for the component

Example configuration of the component:

extensions:
  headers_setter:
    headers:
      - key: X-Scope-OrgID
        from_context: tenant_id
      - key: User-ID
        value: some_user_id

Example of the new component usage to address multi-tenancy use case in Grafana Loki:

extensions:
  headers_setter:
    headers:
      - key: X-Scope-OrgID
        from_context: tenant_id

receivers:
  otlp:
    protocols:
      http:
        include_metadata: true

processors:
  nop:

exporters:
  loki:
    labels:
      resource:
        container_id: ""
        container_name: ""
    endpoint: https://localhost:<port>/loki/api/v1/push
    auth:
      authenticator: headers_setter

service:
  extensions: [ headers_setter ]
  pipelines:
    traces:
      receivers: [otlp]
      processors: [nop]
      exporters: [loki]

Telemetry data types supported

Signal agnostic.

Is this a vendor-specific component? If so, are you proposing to contribute this as a representative of the vendor?

It is not a vendor-specific component.

Sponsor (Optional)

@jpkrohling #12892 (comment)