# Checkpoint with prometheus

## Monitoring Integration with Prometheus and Alert.

***

### Introduction

In this guide, we will set up a **script** to monitor data from an API. This script will expose metrics to **Prometheus**. We will also configure **alerts in Prometheus** to notify when a specific **signer** and **ID** are missing.

***

### 1: Installing Dependencies

You need to install the `requests` library to make the request to the API and `prometheus_client` to expose the metrics to Prometheus.

```bash
pip install requests prometheus_client
```

#### Step 1.1: Create the Monitoring Script

```bash
import requests
from prometheus_client import start_http_server, Gauge
import time

missing_signers_gauge = Gauge('missing_signers', 'Number of missing signers')

target_signer = "<YOUR-SIGNER>"
target_id = "<YOUR-IDVALIDATOR>"

def fetch_missing_signers():
    url = 'https://monitor.vn.stakepool.dev.br/missing_signers'
    try:
        response = requests.get(url)
        response.raise_for_status()  

       
        try:
            data = response.json()
            return data
        except ValueError:
            print(f"Error decoding JSON: Malformed response. Content: {response.text}")
            return []  

    except requests.exceptions.HTTPError as err:
        print(f"Error HTTP: {err}")
    except requests.exceptions.RequestException as err:
        print(f"Error request: {err}")

    return [] 

def update_metrics():
    missing_signers = fetch_missing_signers()
    
   
    if isinstance(missing_signers, list):
        target_found = any(
            signer['signer'] == target_signer and signer['ID'] == target_id
            for signer in missing_signers
        )

        if target_found:
            missing_signers_gauge.set(1)
        else:
            missing_signers_gauge.set(0)
    else:
        print("Invalid response format. Expected a list.")

if __name__ == "__main__":
    start_http_server(8000)
    while True:
        update_metrics()
        time.sleep(60)


```

### 2: Install and Configure Prometheus

#### Step 2.1: Configure Prometheus to Scrape Metrics

Edit the `prometheus.yml` file to include the scrape target for the Python script. Add the following configuration to `prometheus.yml`:

```bash
scrape_configs:
  - job_name: 'missing_signers'
    static_configs:
      - targets: ['localhost:8000']

```

### 3: Configure Prometheus Alerting Rule

Create a new file named `alert.rules` and define the alerting rule for when the specific **signer** and **ID** are missing:

```bash
groups:
  - name: missing_signer_alerts
    rules:
    - alert: MissingSignerAlert
      expr: missing_signers == 1
      for: 1m
      labels:
        severity: critical
    
```

#### Step 3.1: Update Prometheus Configuration to Include Alerts

Add the `alert.rules` file to the Prometheus. Update `prometheus.yml` to include the `rule_files` section:

```bash
rule_files:
  - "alert.rules"

```

3.2 Restart Prometheus

```bash
systemctl restart prometheus
```

### 4. Creating a New Panel

Follow these steps to create a panel in Grafana.

#### Steps:

1. On the Grafana dashboard, click the **"+"** icon in the left sidebar and select **"Dashboard"**.
2. Click on **"Add New Panel"**.

Defining the Query for the `missing_signers` Metrics

With the panel created, the next step is to define the query to display the `missing_signers` metric.

#### Steps:

In the **Query** section (just below "Metric"), select **Prometheus** as the data source.

In the query field, enter the following query:

```plaintext
missing_signers
```

<figure><img src="/files/4J9kcIvykyoHUMRbe87P" alt=""><figcaption></figcaption></figure>

1. In the Grafana panel, click the **Alert** icon (next to the panel title).
2. Configure the alert condition. For example, set it to trigger an alert when the value of `missing_signers` is equal to 1 (which means the specific signer is missing).


---

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