---
title: "Monitor structured logs with Grafana Alloy | Grafana Cloud documentation"
description: "Learn how to use Grafana Alloy to monitor structured logs"
---

# Monitor structured logs with Grafana Alloy

Structured logs use a consistent format, such as JSON, to organize data into key-value pairs. This format makes it easier to search, filter, and analyze log data. With Alloy, you can collect your logs, forward them to a Grafana stack, and create dashboards to monitor your system behavior.

The [`alloy-scenarios`](https://github.com/grafana/alloy-scenarios/) repository contains complete examples of Alloy deployments. Clone the repository and use the examples to understand how Alloy collects, processes, and exports telemetry signals.

In this example scenario, Alloy collects log entries over HTTP, parses them into labels and structured metadata, and forwards the results to a Loki destination.

## Before you begin

Ensure you have the following:

- [Docker](https://www.docker.com/)
- [Git](https://git-scm.com/)

> Note
> 
> You need administrator privileges to run `docker` commands.

## Clone and deploy the example

Follow these steps to clone the scenarios repository and deploy the monitoring example:

1. Clone the Alloy scenarios repository:
   
   shell ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```shell
   git clone https://github.com/grafana/alloy-scenarios.git
   ```
2. Start Docker to deploy the Grafana stack:
   
   shell ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```shell
   cd alloy-scenarios/mail-house
   docker compose up -d
   ```
   
   Verify the status of the Docker containers:
   
   shell ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```shell
   docker ps
   ```
3. (Optional) Stop Docker to shut down the Grafana stack when you finish exploring this example:
   
   shell ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```shell
   docker compose down
   ```

## Monitor and visualize your data

Use Grafana to monitor your deployment’s health and visualize your data.

### Monitor Alloy

To monitor the health of your Alloy deployment, open your browser and go to [http://localhost:12345](http://localhost:12345).

For more information about the Alloy UI, refer to [Debug Grafana Alloy](/docs/grafana-cloud/send-data/alloy/troubleshoot/debug/).

### Visualize your data

To use the Grafana Logs Drilldown, open your browser and go to [http://localhost:3000/a/grafana-lokiexplore-app](http://localhost:3000/a/grafana-lokiexplore-app).

To create a [dashboard](/docs/grafana/latest/getting-started/build-first-dashboard/#create-a-dashboard) to visualize your metrics and logs, open your browser and go to [http://localhost:3000/dashboards](http://localhost:3000/dashboards).

## Understand the Alloy configuration

This example uses a `config.alloy` file to configure the Alloy components for logging. You can find the `config.alloy` file in the cloned repository at `alloy-scenarios/mail-house/`.

The configuration includes `livedebugging` to stream real-time data to the Alloy UI.

### Configure `livedebugging`

`livedebugging` streams real-time data from your components directly to the Alloy UI. Refer to the [Troubleshooting documentation](/docs/grafana-cloud/send-data/alloy/troubleshoot/debug/#live-debugging-page) for more details about this feature.

#### `livedebugging`

`livedebugging` is disabled by default. Enable it explicitly through the `livedebugging` configuration block to make debugging data visible in the Alloy UI.

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

```alloy
livedebugging {
  enabled = true
}
```

### Configure logging

The logging configuration in this example requires three components:

- `loki.source.api`
- `loki.process`
- `loki.write`

#### `loki.source.api`

The [`loki.source.api`](/docs/grafana-cloud/send-data/alloy/reference/components/loki/loki.source.api/) component receives log entries over HTTP and forwards them to other Loki components. In this example, the component requires the following arguments:

- `listen_address`: The network address the server listens to for new connections. Setting this argument to `0.0.0.0` tells the server to listen on all IP addresses.
- `listen_port`: The port the server listens to for new connections.
- `forward_to`: The list of receivers to send log entries to.

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

```alloy
loki.source.api "loki_push_api" {
    http {
        listen_address = "0.0.0.0"
        listen_port = 9999
    }
    forward_to = [
        loki.process.labels.receiver,
    ]
}
```

#### `loki.process`

The [`loki.process`](/docs/grafana-cloud/send-data/alloy/reference/components/loki/loki.process/) component receives log entries from other Loki components, applies processing stages, and forwards the results to the list of receivers. In this example, the component requires the following arguments:

- `expressions`: Key-value pairs defining the name of the data extracted and the value it’s populated with.
- `source`: Name from extracted values map to use for the timestamp.
- `format`: Determines how to parse the source string.
- `values`: Key-value pairs defining the label to set and how to look them up.
- `forward_to`: The list of receivers to send log entries to.

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

```alloy
loki.process "labels" {
    stage.json {
      expressions = { 
                      "timestamp" = "",
                      "state" = "", 
                      "package_size" = "", 
                      "package_status" = "", 
                      "package_id" = "",
                    }
    }

  stage.timestamp {
    source = "timestamp"
    format = "RFC3339"
  }

  stage.labels {
    values = {
      "state" = "",
      "package_size" = "",
    }
  }

  stage.structured_metadata {
    values = {
      "package_status" = "",
      "package_id" = "",
    }
  }

  stage.static_labels {
    values = {
      "service_name" = "Delivery World",
    }
  }

  stage.output {
    source = "message"
  }

  forward_to = [loki.write.local.receiver]
}
```

#### `loki.write`

The [`loki.write`](/docs/grafana-cloud/send-data/alloy/reference/components/loki/loki.write/) component writes logs to a Loki destination. In this example, the component requires the following argument:

- `url`: Defines the full URL endpoint in Loki to send logs to.

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

```alloy
loki.write "local" {
  endpoint {
    url = "http://loki:3100/loki/api/v1/push"
  }
}
```