Extend configuration syntax so received metadata or span attributes can be used as dynamic values to set on processors or exporters

[D Martin]

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

• Need to pass through metadata from a grpc receiver, into an otlp exporter header

Describe the solution you'd like

exporters:
  otlp:
      endpoint: "http://some-endpoint:4317/"
      headers:
        my-data1: ":metadata.data1"

or

exporters:
  otlp:
      endpoint: "http://some-endpoint:4317/"
      headers:
        my-data1: ":attributes.data1"

[patst]

would love to see that as well. We use Grafana Tempo as backend to export to and multiple tenants could share a OpenTelemetryCollector.

We could extract the tenantId from an kubernetes namespace and then set the x-scope-orgid http header based on the extracted label