Is it possible to set an extra header for the Prometheus remote write exporter based on a metric-specific label?

[romm333]

am trying to send a metric stream exported from my .NET Core application to the Prometheus remote write exporter. On the C# side metric is decorated with the custom label:

forecastRequestsCounter.Add(1, new KeyValuePair<string, object?>("request_tenant_id", appId));

I see this label in the metrics storage and can use it for filtering by labels in Grafana. Is it possible to extract the 'request_tenant_id' label when it enters the Otel collector pipeline and set it as a custom header for the Prometheus remotewrite exporter using some suitable processor? I tried headers_setter, but it does not seem right for this case.

example of my collector config file:

extensions:
health_check: {}
headers_setter:
headers:
- action: insert
key: X-Scope-OrgID
from_context: tenant_id

prometheusremotewrite/metrics:
endpoint: .......
tls:
insecure: true
auth:
authenticator: headers_setter
resource_to_telemetry_conversion:
enabled: true
target_info:
enabled: false

service:
extensions:
- headers_setter
pipelines:
metrics:
receivers:
- otlp
exporters:
- prometheusremotewrite/metrics

The headers_setter in this case cannot access the metric labels, defined in my c# code.

The main motivation back this post is a need to set X-Scope-OrgID dynamically in a runtime,
Have found one discussion about that from the pasty year: open-telemetry/opentelemetry-go#5129
Not sure if this feature was/will be implemented..

Br