Prometheus relabel within prometheus.scrape component for params in Flow mode

[Whyeasy]

Request

Within the agent in static mode (or Prometheus) it is possible to access provided params inside of the relabel config like this:

scrape_configs:
  - job_name: blackbox
    metrics_path: /probe
    scrape_interval: 60s
       params:
         module: [<module_name>]
         target:
           [<URL>]
       relabel_configs:
         - source_labels: [__param_module]
           target_label: module

With Flow and the components that come with it, it is currently not possible to access these __param_ values. They are added within a prometheus.scrape component. Which discards any __ labels when it forwards to a remote write endpoint.

This is the current configuration used to work around this issue:

// Discover the blackbox exporter pods
discovery.kubernetes "k8s_pods_blackbox"{
  role = "pod"

  namespaces {
    names = [
        "grafana-agent",
    ]
  }
}

discovery.relabel "blackbox_exporter" {
  targets = discovery.kubernetes.k8s_pods_blackbox.targets

  rule {
    source_labels = [
      "__meta_kubernetes_pod_label_app_kubernetes_io_name",
    ]
    action = "keep"
    regex = "prometheus-blackbox-exporter"
  }

  rule {
    source_labels = [
      "__address__",
      "__meta_kubernetes_service_annotation_prometheus_io_port",
    ]
    regex = "(.+):(?:d+);(d+)"
    replacement = "${1}:${2}"
    target_label = "__address__"
  }

  rule {
    source_labels = [
      "__meta_kubernetes_pod_name",
    ]
    target_label = "pod"
  }

  rule {
    replacement = "blackbox_exporter"
    target_label = "app"
  }
}

discovery.relabel "blackbox_exporter_<module>" {
  targets = discovery.relabel.blackbox_exporter.output

  rule {
    source_labels = [
      "instance",
    ]
    target_label = "instance"
    replacement = "<URL>"
  }

  rule {
    replacement = "<module_name>"
    target_label = "module"
  }
}

prometheus.scrape "blackbox_<module>" {
  targets    = discovery.relabel.blackbox_exporter_<module>.output
  forward_to = [prometheus.remote_write.prom.receiver]
  scrape_interval = "60s"
  metrics_path = "/probe"
  params = {
    "module" = ["<module_name>"],
    "target" = ["<URL>"],
  }
}

Use case

The workaround is to create a separate discovery.relabel component for each different module/target. Would be great to have a way to have access to the __param_module label inside or after the prometheus.scrape component. This will simplify the config.

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[ghobadimhd]

Hello. I have a same problem here. Is there updates on this?