---
title: "prometheus.enrich | Grafana Alloy documentation"
description: "The prometheus.enrich component enriches metrics with labels from service discovery"
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

# `prometheus.enrich`

> **EXPERIMENTAL**: This is an [experimental](/docs/release-life-cycle/) component. Experimental components are subject to frequent breaking changes, and may be removed with no equivalent replacement. To enable and use an experimental component, you must set the `stability.level` [flag](/docs/alloy/next/reference/cli/run/) to `experimental`.

The `prometheus.enrich` component enriches metrics with additional labels from service discovery targets. It matches labels from incoming metrics against labels from discovered targets, and copies specified labels from the matched target to the metric sample. If no match occurs, the metrics are passed through unchanged.

Use the `target_to_metric_match` argument to specify which target labels correspond to which metric labels. The map keys are target label names and the values are the corresponding metric label names. All labels in the map must match for enrichment to occur.

> Warning
> 
> The `target_match_label` and `metrics_match_label` arguments are deprecated in favor of `target_to_metric_match`. If `target_to_metric_match` is set, it takes precedence. Replace `target_match_label = "hostname"` with `target_to_metric_match = {"hostname" = "hostname"}`. These deprecated arguments will be removed in a future release.

## Usage

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
prometheus.enrich "<LABEL>" {
  targets = <DISCOVERY_COMPONENT>.targets

  target_to_metric_match = {
    "<TARGET_LABEL_1>" = "<METRIC_LABEL_1>",
    "<TARGET_LABEL_2>" = "<METRIC_LABEL_2>",
  }

  forward_to = [<RECEIVER_LIST>]
}
```

## Arguments

You can use the following arguments with `prometheus.enrich`:

Expand table

| Name                     | Type                    | Description                                                                                                     | Default | Required |
|--------------------------|-------------------------|-----------------------------------------------------------------------------------------------------------------|---------|----------|
| `forward_to`             | `list(MetricsReceiver)` | Where the metrics should be forwarded to, after enrichment.                                                     |         | yes      |
| `targets`                | `list(map(string))`     | List of targets from a discovery component.                                                                     |         | yes      |
| `target_to_metric_match` | `map(string)`           | Map of target label name to metric label name. All entries must match for enrichment.                           |         | no       |
| `target_match_label`     | `string`                | (Deprecated) The label from discovered targets to match against, for example, `"__inventory_consul_service"`.   |         | no       |
| `metrics_match_label`    | `string`                | (Deprecated) The label from incoming metrics to match against discovered targets, for example `"service_name"`. |         | no       |
| `labels_to_copy`         | `list(string)`          | List of labels to copy from discovered targets to metrics. If empty, all labels are copied.                     |         | no       |

## Blocks

The `prometheus.enrich` component doesn’t support any blocks. You can configure this component with arguments.

## Exports

The following values are exported:

Expand table

| Name       | Type              | Description                                               |
|------------|-------------------|-----------------------------------------------------------|
| `receiver` | `MetricsReceiver` | The input receiver where samples are sent to be enriched. |

## Debug information

`prometheus.enrich` doesn’t expose any component-specific debug information.

## Debug metrics

- `prometheus_fanout_latency` (histogram): Write latency for sending to direct and indirect components.
- `prometheus_forwarded_samples_total` (counter): Total number of samples sent to downstream components.
- `prometheus_target_cache_size` (gauge): Total number of cached target entries.

## Examples

### Enrich metrics from `prometheus.scrape`

The following example shows how the `prometheus.enrich` enriches incoming metrics from `prometheus.scrape.default`, using HTTP discovery, and forwards the results to `prometheus.remote_write.default` component:

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
discovery.http "default" {
    url = "http://network-inventory.example.com/prometheus_sd"
}

prometheus.scrape "default" {
  targets = [
    {"__address__" = "example-app:9001"},
  ]

  forward_to = [prometheus.enrich.default.receiver]
}

prometheus.enrich "default" {
	targets = discovery.http.default.targets

	target_to_metric_match = {
		"hostname" = "hostname",
	}

	forward_to = [prometheus.remote_write.default.receiver]
}

prometheus.remote_write "default" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}
```

### Enrich metrics from `prometheus.receive_http`

The following example shows how the `prometheus.enrich` enriches incoming metrics from `prometheus.receive_http.default`, using file-based discovery, and forwards the results to `prometheus.remote_write.default` component:

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
discovery.file "network_devices" {
   files = ["/etc/alloy/devices.json"]
}

prometheus.receive_http "default" {
  http {
    listen_address = "0.0.0.0"
    listen_port = 9999
  }

  forward_to = [prometheus.enrich.default.receiver]
}

prometheus.enrich "default" {
    targets = discovery.file.network_devices.targets

    target_to_metric_match = {
        "hostname" = "hostname",
    }

    forward_to = [prometheus.remote_write.default.receiver]
}

prometheus.remote_write "default" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}
```

### Multi-label matching with Kubernetes metadata

The following example enriches cadvisor metrics with Kubernetes Pod metadata, matching on namespace, Pod, and container labels simultaneously.

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
discovery.kubernetes "pods" {
  role = "pod"
}

prometheus.scrape "cadvisor" {
  targets = [
    {"__address__" = "localhost:10250", "__metrics_path__" = "/metrics/cadvisor"},
  ]
  scheme = "https"

  forward_to = [prometheus.enrich.k8s_meta.receiver]
}

prometheus.enrich "k8s_meta" {
    targets = discovery.kubernetes.pods.targets

    target_to_metric_match = {
        "__meta_kubernetes_namespace"          = "namespace",
        "__meta_kubernetes_pod_name"           = "pod",
        "__meta_kubernetes_pod_container_name" = "container",
    }

    labels_to_copy = ["__meta_kubernetes_pod_node_name", "__meta_kubernetes_pod_label_app"]

    forward_to = [prometheus.remote_write.default.receiver]
}

prometheus.remote_write "default" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}
```

## Compatible components

`prometheus.enrich` can accept arguments from the following components:

- Components that export [Targets](../../../compatibility/#targets-exporters)
- Components that export [Prometheus `MetricsReceiver`](../../../compatibility/#prometheus-metricsreceiver-exporters)

`prometheus.enrich` has exports that can be consumed by the following components:

- Components that consume [Prometheus `MetricsReceiver`](../../../compatibility/#prometheus-metricsreceiver-consumers)

> Note
> 
> Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.