> ## Documentation Index
> Fetch the complete documentation index at: https://docs.honeycomb.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Lookup Fields

<Badge className="hny-badge-enterprise-addon" stroke>Ent+</Badge>

<Note>
  This feature is available as an add-on for the [Honeycomb Enterprise plan](https://www.honeycomb.io/pricing/).
  Please contact your Honeycomb account team for details.
</Note>

## Description

The Lookup Fields processor can be used to add matching telemetry fields from a CSV file.

## Use

The Lookup Fields processor is used to dynamically add fields based on an existing telemetry value. For each unit of telemetry processed, this processor will
grab the value of a field and perform a lookup using a CSV file. If that value exists, the processor will add all other fields associated with that CSV row.

The processor re-reads the CSV file every 60 seconds, allowing updates to be made without restarting the agent.

## Supported Types

| Metrics | Logs | Traces | Telemetry Pipeline Agent |
| :------ | :--- | :----- | :----------------------- |
| ✓       | ✓    | ✓      | `v1.45.0\`+              |

## Configuration

| Field   | Description                                                                                                                                                                    |
| :------ | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| CSV     | The CSV file used to perform a lookup operation.                                                                                                                               |
| Context | The context of the lookup operation. The source field must exist here in order to perform a lookup. If a lookup succeeds, all matching fields are also added to this location. |
| Field   | The field to lookup in the specified context. A lookup operation is performed if the name and value of this field match a header and value in the CSV file.                    |

## Example Configuration(s)

### Adding Fields Based on Host

In this configuration, the processor will perform a lookup on the `host.name` value of all incoming metrics. If this field exists on the resource of a metric and the specified CSV file contains a matching value with that header, all other fields in that CSV row will be added to the metric. For example, in this particular configuration, if a metric has a value of `MacBook-Pro-4.local` for `host.name`, the corresponding values for `region` and `env` will automatically be added to the same context.

#### Web Interface

<img src="https://mintcdn.com/honeycomb/yjwgE9IWY42i02gc/_assets/images/htp/xnapper-lookup-fields.png?fit=max&auto=format&n=yjwgE9IWY42i02gc&q=85&s=d0fbd1cc9f459fbd4cca93a298066423" alt="Honeycomb Docs - Lookup Fields - image 1" width="1946" height="1912" data-path="_assets/images/htp/xnapper-lookup-fields.png" />

#### Example CSV

```csv theme={}
host.name,region,env
MacBook-Pro-4.local,us-east,prod
MacBook-Pro-3.local,us-west,dev
MacBook-Pro-2.local,us-central,dev
MacBook-Pro-1.local,us-central,prod
```